Product Guides
Socket Size Chart: Metric, Imperial & Drive Sizes
Socket size is the across-flats (AF) measurement of a fastener head, sized in millimetres (metric) or fractions of an inch (imperial/SAE). A 19mm socket equals 3/4" (19.05mm). The quick-reference table below lists the most-used sizes in both systems; full metric, imperial and drive-size charts are further down. Quick answer — socket conversions Metric → Imperial: 8mm ≈ 5/16" · 10mm ≈ 3/8" · 11mm ≈ 7/16" · 13mm ≈ 1/2" · 14mm ≈ 9/16" · 15mm ≈ 19/32" · 16mm ≈ 5/8" · 17mm ≈ 11/16" · 19mm ≈ 3/4" · 21mm ≈ 13/16" · 22mm ≈ 7/8" · 24mm ≈ 15/16" · 27mm ≈ 1-1/16" · 30mm ≈ 1-3/16" Imperial → Metric: 1/4" ≈ 6.5mm · 5/16" ≈ 8mm · 3/8" ≈ 10mm · 7/16" ≈ 11mm · 1/2" ≈ 13mm · 9/16" ≈ 14mm · 5/8" ≈ 16mm · 3/4" ≈ 19mm · 7/8" ≈ 22mm · 15/16" ≈ 24mm ⚠️ Close ≠ exact. For torqued fasteners always use the correct system to avoid rounding the head. For more engineering reference charts and selection tables, see our Engineering Reference Charts hub — covering fasteners, bearings, lubrication, measuring, welding and Australian standards. Socket Size Selector — Find the Right Socket for the Job This chart is a working socket selector — every chart row links to a stocked AIMS product (Ko-Ken, Stahlwille or Trax) or to the matching range. Use the scenarios below to land on the right drive size + socket size fast, or scroll to the chart tables below. How to use: 1. Match drive size to job type 2. Find the metric or imperial socket size in the chart 3. Click the size to view the stocked product Electronics & Small Screws 1/4" drive — fine work 1/4" View → General Workshop 3/8" drive — most-common 3/8" View → Automotive & Engineering 1/2" drive — bolts to M22 1/2" View → Heavy Truck & Mining 3/4" drive — high-torque 3/4" View → Impact / Air Tools Impact-rated black sockets Impact View → Torx & Hex Drive Bolts Torx & hex bit sockets Torx/Hex View → Browse Socket Sets Multi-piece complete sets Sets View → Ko-Ken / Stahlwille / Trax Top brands stocked Brands View → Quick rule: 1/4" drive for small jobs (electronics, dash trim), 3/8" for general workshop and automotive, 1/2" for chassis and engine bolts (M10-M22), 3/4" for heavy truck and mining (M24+). For impact tools, use black impact-rated sockets only — chrome sockets shatter under hammer load. Need help? Call (02) 9773 0122. Jump to: How Sockets Work Metric 1/4" Metric 3/8" Metric 1/2" Imperial SAE Conversion Deep vs Standard Choosing Drive Size Related Selectors Socket Size Chart — Metric to Imperial Quick Reference The most common metric socket sizes and their closest imperial (SAE) equivalents: Metric Imperial (SAE) Metric Imperial (SAE) 8mm 5/16" 17mm 11/16" 10mm 3/8" 19mm 3/4" 11mm 7/16" 22mm 7/8" 13mm 1/2" 24mm 15/16" 14mm 9/16" 27mm 1-1/16" How Socket Sizes Work Socket sizes refer to the across-flats measurement of the fastener head — the same dimension used for spanners and open-end wrenches. A 19mm socket fits a fastener with 19mm across the flats, regardless of whether the fastener itself is metric or has a metric thread. Drive size is separate from socket size. It refers to the square drive on the ratchet or extension bar that connects to the socket — 1/4", 3/8" or 1/2". A 3/8" drive 13mm socket and a 1/2" drive 13mm socket both fit the same nut, but the larger drive handles more torque. Standard (shallow) sockets work for most fasteners. Deep sockets are needed where the fastener shank protrudes through the nut — common on wheel studs, bolts with long thread engagement, and spark plugs. Metric Socket Size Chart — 1/4" Drive A 1/4" drive is suited to light work: electronics, small engines, interior trim, and torque-sensitive applications. Typical range is 4mm–15mm. Handles up to approximately 35 Nm. Socket Size (mm) Drive Size Typical Use 4 1/4" Small screws, electronics 5 1/4" Small fasteners 5.5 1/4" Small engine components 6 1/4" General light fasteners 7 1/4" General light fasteners 8 1/4" Interior panels, brackets 9 1/4" General use 10 1/4" Most common metric bolt head 11 1/4" General use 12 1/4" General use 13 1/4" M8 bolt head 14 1/4" General use 15 1/4" Upper limit of 1/4" drive Metric Socket Size Chart — 3/8" Drive A 3/8" drive covers the widest general-purpose range — from 8mm up to 24mm in most sets. The right choice for most automotive, machinery, and workshop tasks. Handles up to approximately 100–135 Nm. Socket Size (mm) Drive Size Common Fastener 8 3/8" M5 bolt head 9 3/8" General use 10 3/8" M6 bolt head — most common 11 3/8" General use 12 3/8" M8 bolt head (some) 13 3/8" M8 bolt head (standard) 14 3/8" M9 bolt head 15 3/8" General use 16 3/8" M10 bolt head (some) 17 3/8" M10 bolt head (standard) 18 3/8" M11 bolt head 19 3/8" M12 bolt head / wheel nuts (many) 21 3/8" General use 22 3/8" M14 bolt head 24 3/8" M16 bolt head Metric Socket Size Chart — 1/2" Drive A 1/2" drive is for heavy work: wheel nuts, suspension components, heavy machinery, and high-torque fasteners. Standard range is 17mm–50mm. Handles 200 Nm and above depending on the tool. Socket Size (mm) Drive Size Common Fastener 17 1/2" M10 bolt head 19 1/2" M12 bolt head / most wheel nuts 21 1/2" General heavy use 22 1/2" M14 bolt head 24 1/2" M16 bolt head 27 1/2" M18 bolt head 30 1/2" M20 bolt head 32 1/2" M22 bolt head 33 1/2" Wheel nuts (heavy vehicles) 36 1/2" M24 bolt head 38 1/2" Heavy machinery 41 1/2" Heavy machinery / axle nuts 46 1/2" Axle nuts / heavy plant 50 1/2" Large axle and hub nuts Imperial (SAE) Socket Size Chart Imperial sockets are sized in fractions of an inch and are common on American-manufactured vehicles and equipment, agricultural machinery, and older plant. The sizing convention follows SAE (Society of Automotive Engineers) standards. Available in 1/4", 3/8" and 1/2" drive. Socket Size (inch) Decimal (inch) Metric Equivalent (mm) Typical Drive 3/16" 0.188" 4.8 1/4" 1/4" 0.250" 6.35 1/4" 5/16" 0.313" 7.9 1/4" 3/8" 0.375" 9.5 1/4" / 3/8" 7/16" 0.438" 11.1 3/8" 1/2" 0.500" 12.7 3/8" 9/16" 0.563" 14.3 3/8" 5/8" 0.625" 15.9 3/8" 11/16" 0.688" 17.5 3/8" 3/4" 0.750" 19.1 3/8" / 1/2" 13/16" 0.813" 20.6 3/8" / 1/2" 7/8" 0.875" 22.2 1/2" 15/16" 0.938" 23.8 1/2" 1" 1.000" 25.4 1/2" 1-1/16" 1.063" 27.0 1/2" 1-1/8" 1.125" 28.6 1/2" 1-3/16" 1.188" 30.2 1/2" 1-1/4" 1.250" 31.8 1/2" 1-5/16" 1.313" 33.3 1/2" 1-3/8" 1.375" 34.9 1/2" 1-1/2" 1.500" 38.1 1/2" Metric to Imperial Socket Conversion Chart No exact metric-to-imperial match exists — socket sizes are based on different measurement systems. The table below shows the closest imperial socket to each common metric size. In most cases the fit will be too loose for torquing; use the correct metric socket where precision matters. Metric Size (mm) Closest Imperial Difference 8 5/16" +0.1mm 9 3/8" +0.5mm 10 3/8" -0.5mm 11 7/16" +0.1mm 12 15/32" -0.1mm 13 1/2" -0.3mm 14 9/16" +0.3mm 15 19/32" +0.0mm 16 5/8" -0.1mm 17 11/16" +0.5mm 18 11/16" -0.5mm 19 3/4" +0.1mm 21 13/16" -0.6mm 22 7/8" +0.2mm 24 15/16" -0.2mm 27 1-1/16" +0.0mm 30 1-3/16" +0.2mm 32 1-1/4" -0.2mm Standard vs Deep Socket Guide Standard (shallow) sockets handle the vast majority of work. Deep sockets are needed when the bolt shank extends through the nut, leaving the socket unable to seat properly on a shallow socket. Common applications for deep sockets include wheel studs, exhaust bolts, spark plugs, and any application where thread is exposed above the nut. Socket Type Depth Use When Standard (shallow) ~25–35mm Bolt head or nut flush / minimal thread protrusion Deep ~60–75mm Thread protrudes through nut (wheel studs, spark plugs) Extra deep / pass-through 100mm+ Long studs, threaded rod, specialised applications Choosing the Right Drive Size Drive size determines torque capacity and tool compatibility. Match the drive to the job — using a 1/2" drive on small fasteners risks overtorquing and rounding; using a 1/4" drive on large fasteners risks snapping the drive or the socket. Drive Size Socket Range Torque Range Typical Applications 1/4" 4–15mm / 3/16"–9/16" Up to ~35 Nm Electronics, small engines, interior trim, torque-sensitive work 3/8" 8–24mm / 5/16"–15/16" 35–135 Nm General automotive, machinery, most workshop tasks 1/2" 17–50mm+ / 11/16"–2" 135 Nm+ Wheel nuts, suspension, heavy machinery, high-torque fasteners 3/4" 33–75mm+ 700 Nm+ Heavy plant, earthmoving, structural work 1" 50mm+ 2,000 Nm+ Mining, large infrastructure, industrial plant Related AIMS Selectors This selector pairs with AIMS's other fastener & tool guides: Spanner Size Chart — metric AF spanner sizes mapped to bolt size + spanner products. Choosing Socket Drive Size — detailed walkthrough on when to step up or down a drive size. Ratchet Spanner Guide — flex-head vs reversible vs gear count selection. Adjustable Spanner Guide — shifter selection and use. Types of Spanners — open-end / ring / combo / flare / podger reference. Impact Driver vs Impact Wrench — when to use impact sockets vs hand tools. Socket Head Cap Screw Guide — Allen/hex socket fastener reference (paired with socket bits). Metric Bolt Torque Chart — torque values per grade and size (use with torque wrench). Or browse the full sockets range, ratchets & sockets, spanners & wrenches, or by brand: Ko-Ken, Stahlwille, Trax. Next-day Australia-wide dispatch from our Milperra warehouse.Frequently Asked Questions What is 10mm socket in imperial? A 10mm socket is approximately 3/8 inch (9.525mm). The match is close — 10mm is 0.475mm larger — but for torqued fasteners always use the 10mm socket on metric bolts. 10mm fits M6 bolt heads which are extremely common on engines and brackets. Is 3/8 inch socket the same as 10mm? No, they are close but not identical. A 3/8 inch socket measures 9.525mm and a 10mm socket measures 10mm — a 0.475mm difference. A 3/8" socket will fit loosely on a 10mm hex and risks rounding the head under torque. Use the correct system for the fastener. What is 13mm socket in imperial? A 13mm socket is approximately 1/2 inch (12.7mm). The difference is only 0.3mm. 13mm is the standard size for M8 hex bolts — one of the most-used sizes in automotive and machinery work. What is 14mm socket in imperial? A 14mm socket is approximately 9/16 inch (14.29mm). 14mm is commonly used for M10 hex bolts, brake calipers and many engine fasteners. What is 15mm socket in imperial? A 15mm socket is approximately 19/32 inch (15.08mm). 15mm is less common in the standard imperial range — most SAE sets skip from 9/16" (14.29mm) to 5/8" (15.88mm). What is 16mm socket in imperial? A 16mm socket is approximately 5/8 inch (15.88mm). 5/8" is 0.125mm smaller than 16mm — usable on a light fit but always use 16mm for torqued M10 fine-thread fasteners. What is 17mm socket in imperial? A 17mm socket is approximately 11/16 inch (17.46mm). 17mm is one of the most common sizes used on M10 hex bolt heads and brake hardware. What is 19mm socket in imperial? A 19mm socket is equivalent to 3/4 inch (19.05mm) — only 0.05mm difference. This is one of the closest metric/imperial pairs and either socket can usually be used interchangeably on a light fit. What is 21mm socket in imperial? A 21mm socket is approximately 13/16 inch (20.64mm). 21mm is the standard size for many wheel lug nuts on European vehicles. What is 22mm socket in standard? A 22mm socket is approximately 7/8 inch (22.23mm). 22mm is widely used on M14 hex bolts and is a common spark plug socket size. What is 28mm socket in imperial? A 28mm socket is approximately 1-1/8 inch (28.58mm). The difference is 0.58mm — use the correct metric size for axle nuts and large machinery fasteners. What are socket sizes in order? Common metric socket sizes in order: 4, 4.5, 5, 5.5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 27, 30, 32, 36mm. Common imperial (SAE) sizes in order: 5/32, 3/16, 7/32, 1/4, 9/32, 5/16, 11/32, 3/8, 7/16, 1/2, 9/16, 5/8, 11/16, 3/4, 13/16, 7/8, 15/16, 1, 1-1/16, 1-1/8 inch. What is the most common socket size? In metric, 10mm is the most frequently used socket size — it fits M6 bolt heads which appear on engines, brackets and interior components across virtually every vehicle and machine. In imperial, 3/8" and 7/16" are among the most common SAE sizes. Can I use a metric socket on an imperial fastener? In some cases yes — where the metric size is very close to the imperial size. For example, an 11mm socket is almost identical to a 7/16" (11.1mm). However, for torqued fasteners, always use the matching socket to avoid rounding. The closest metric-to-imperial matches are shown in the conversion chart above. When do I need a deep socket? Use a deep socket when the bolt shank protrudes through the nut, preventing a standard socket from seating properly. Common applications include wheel studs (where the thread extends past the wheel nut), spark plugs, and long threaded rod assemblies. If a standard socket rocks or won't engage the full depth of the hex, switch to a deep socket. What is the difference between 6-point and 12-point sockets? A 6-point socket has six internal contact points and grips the flat sides of the hex fastener. It is less likely to round worn or corroded fasteners and is the preferred choice for high-torque work. A 12-point socket has twelve contact points, allowing it to engage the fastener at more angles — useful in tight spaces where swing is limited. For general use, 6-point is the better choice. Ready to get to work? Shop our full range of sockets & socket sets From 1/4" drive metric to 1/2" drive imperial — AIMS Industrial stocks sockets for every drive size and standard, ready to ship Australia-wide. Browse sockets Talk to a specialist People Also Ask — Socket Size Chart: Metric, Imperial & Drive Sizes Q: What is the difference between 3/8" and 1/2" drive sockets? Drive size refers to the square drive that connects the socket to the ratchet — 3/8" is the most versatile for general trade work, while 1/2" drive handles higher torque applications like wheel nuts and structural bolts. 1/4" drive suits tight spaces and small fasteners; 3/4" and 1" drive are for heavy industrial work. Q: Can I use a metric socket on an imperial bolt? In a pinch, a close-fitting metric socket can work on an imperial fastener — for example, a 15 mm socket is nearly identical to 19/32". However, using a slightly oversized socket risks rounding off the fastener corners. Always use the correct size where possible; keep a mixed metric/imperial set for older equipment. Q: What does 6-point vs 12-point socket mean? A 6-point socket has six contact surfaces and grips flat-to-flat on the hex, reducing the risk of rounding fasteners. A 12-point socket engages on corners, making it easier to position in tight spaces but more likely to slip under high torque. Use 6-point sockets for stuck or high-torque fasteners; 12-point for easy access work. Q: Are impact sockets different from standard sockets? Yes — impact sockets are made from thicker, softer chrome-molybdenum steel that absorbs the hammering action of an impact wrench without shattering. Standard chrome-vanadium hand sockets can crack under impact loads. Impact sockets are typically black (not chrome-plated) for easy identification. Never use hand sockets with impact guns.
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Loctite Application Guide: Which Grade & When to Use It
Loctite Grade Selector — Match Product to Job This guide is a working Loctite selector. Use the cards below to land on the right grade fast — every grade mentioned in the article body also links to its specific AIMS product page. How to use: 1. Match the job profile (threadlock, sealant, retaining, adhesive) 2. Click the grade to view AIMS stock 3. Use the application section below for technique Low-Strength Threadlock Loctite 222 — small fasteners, removable 222 View → Medium-Strength Threadlock Loctite 243 — workshop default 243 View → High-Strength Threadlock Loctite 263 / 271 — permanent / vibration 263/271 View → Pipe Thread Sealing Loctite 567 / 569 / 577 — anaerobic 567/577 View → Bearing Retaining Loctite 638 / 641 — slip-fit retaining 638 View → Gasket Eliminator Loctite 518 / 510 / 587 / 596 518/596 View → Instant Adhesive (CA) Loctite 401 / 406 / 480 401/406 View → Anti-Seize / Surface Prep Loctite Copper Anti-Seize + 7649 Primer Anti-Seize View → Quick rule of thumb: Loctite anaerobics cure where there's metal + absence of oxygen. Low-strength (222) = removable. Medium-strength (243) = workshop default. High-strength (263/271) = permanent / heat-required to remove. AIMS stocks the full Loctite anaerobic + instant adhesive + sealant + activator range. Need help? Call (02) 9773 0122. Jump to: Which Loctite? Loctite Guides Quick Chart Threadlockers Thread Sealants Retaining Anti-Seize Surface Prep Removing Instant Adhesives Related Loctite Guides Each Loctite product family also has its own dedicated category guide — grade-by-grade breakdowns, decision frameworks and FAQs beyond what's covered here. Threadlockers Purple, blue, red and green grades compared — including the 248 and 268 sticks. Full guide → Retaining Compounds Bearing installation, diametral clearance selection and troubleshooting. Full guide → Thread Sealants Hydraulic and pipe sealing — media compatibility and pressure ratings. Full guide → Which Loctite do I use? Loctite threadlockers are colour-coded by strength: blue (Loctite 242 / 243) for medium-strength fasteners you'll need to remove later, red (Loctite 262 / 271 / 277) for permanent high-strength fasteners that stay put, and green (Loctite 290) for wicking into pre-assembled threads. Loctite also makes thread sealants (567 / 577 for tapered pipe threads), retaining compounds (603 / 638 for bearing fits), and instant adhesives (401 / 406 cyanoacrylates). What is Loctite 243 used for? Loctite 243 is a medium-strength blue threadlocker for fasteners between M6 and M20 that you may need to remove later with hand tools. It tolerates light oil contamination on the threads, cures in around 10 minutes to handling strength, and reaches full strength in 24 hours. Typical uses: vehicle suspension bolts, pump and motor fixings, machinery hold-downs, gearbox fasteners. Need another reference chart? Browse the full AIMS Engineering Reference Charts library — drill bit sizes, tap drill, torque, viscosity, GD&T, AS/NZS standards and more. Loctite Quick Selection Chart For threadlocking on small fasteners use Loctite 222 (purple); medium-duty fasteners Loctite 243 (blue); high-strength permanent Loctite 263 or 271 (red). For pipe sealing use Loctite 567 or 577. For retaining compounds use Loctite 638, 641 or 648. Full grade-by-grade detail below. Grade Type / Colour Use For 222 Threadlocker — Purple, low strength Small screws M1.4–M6, grub screws, instruments 243 Threadlocker — Blue, medium strength General fasteners M6–M20, hand-tool removable 263 / 271 Threadlocker — Red, high strength Permanent fasteners — heat required to remove 567 Thread sealant — White Fine hydraulic and pneumatic threads 577 Thread sealant — Yellow BSP and NPT pipe threads, gas, water, oil 638 Retaining compound — High strength Close-tolerance bearing retention 641 Retaining compound — Medium strength Standard bearing / bushing retention 648 Retaining compound — Maximum strength Permanent high-temp cylindrical assemblies 401 Instant adhesive — Cyanoacrylate General-purpose bonding of metal, rubber, plastic 480 Instant adhesive — Toughened CA Impact-resistant rubber and metal bonds What Are Loctite Anaerobic Products? Loctite's industrial range is built on anaerobic chemistry — adhesives and sealants that remain liquid in air but cure rapidly when trapped between two close-fitting metal surfaces in the absence of oxygen. The metal ions in the substrate initiate polymerisation, converting the liquid into a hard thermoset plastic that resists vibration, leakage and corrosion. When stripping a stubborn old anaerobic threadlocker bond, mechanical heat is the standard release method — but for plastic-bodied components where heat is risky, the contrast-cooling trick from our freeze spray guide can shock-fracture cured threadlocker without damaging the surrounding plastic. Quick answer — Loctite grades by job Threadlockers (anaerobic, prevent vibration loosening): 222 low strength (small screws, removable) · 242/243 medium strength (general purpose, blue) · 263/271/277 high strength (permanent, red) · 248 stick form Instant adhesives (cyanoacrylate / super glue): 401 general purpose · 406 rubber/plastic specialty · 414 metals · 480 toughened impact-resistant · 435 low-blooming clear Thread sealants (anaerobic, pipe thread leaks): 567 stainless/coarse (white) · 577 general pipe (yellow, faster cure) · 542 hydraulic fine threads · 545 general purpose Retaining compounds: 603 oil-tolerant · 638 high strength, high temp · 648 high temp, fast cure · 680 slip-fit highest strength This guide covers every industrial Loctite product family relevant to maintenance, engineering and trade work in Australia: threadlockers (preventing fastener loosening under vibration), thread sealants (sealing pipe and hydraulic fittings), and retaining compounds (locking bearings, bushings and cylindrical assemblies). It includes full selection charts, application guides, cure time data, surface preparation requirements and removal instructions — plus a FAQ section that answers the most common grade comparison questions. Browse the full AIMS Industrial Loctite range — threadlockers, thread sealants, retaining compounds and primers stocked for fast Australia-wide dispatch. Loctite Threadlockers: Grades, Colours and Selection Threadlockers prevent fasteners from loosening under vibration, thermal cycling and dynamic load. They fill the microscopic gaps between mating threads, locking out corrosion and sealing against fluid ingress at the same time. Selecting the wrong grade — typically using red where blue is correct, or blue where purple is required — is the most common installation mistake, and can make fasteners impossible to remove without heat or damage the threads on small screws. The Loctite Colour and Strength System Every Loctite threadlocker is colour-coded by strength. The colour tells you immediately whether the fastener can be released with standard hand tools or whether heat will be required for removal. Colour Strength Level Removability Common Grades Purple Low Hand tools — easily removable 222 Blue Medium Hand tools — standard spanners and sockets 242, 243 Red High / Permanent Heat required — 250°C before applying torque 262, 263, 271, 272, 277 Green Low to High (wicking grades) Depends on grade — see table below 270, 290 Loctite Threadlocker Grade Comparison Chart Grade Colour Strength Bolt Size Max Temp Removable? Primary Application 222 Purple Low M1.4–M6 150°C Yes — hand tools Small screws, grub screws, instrument hardware, adjustment fasteners 242 Blue Medium M6–M20 150°C Yes — hand tools General purpose — older formulation; performs identically to 243 on clean threads 243 Blue Medium M6–M20 150°C Yes — hand tools General purpose standard — improved oil tolerance over 242; preferred current-generation grade 262 Red High M6–M20 150°C Heat required (250°C) Studs, press-fit bolts, high-vibration assemblies — smaller fasteners than 263 263 Red High M6–M36 150°C Heat required (250°C) Large permanent fasteners — higher breakaway torque than 262; structural joints 270 Green High M6–M36 150°C Heat required Wicking grade — penetrates pre-assembled joints; post-assembly application 271 Red High M6–M36 150°C Heat required (250°C) High-strength general purpose — wheel bolts, studs, structural and safety-critical fasteners 272 Red High M6–M36 230°C Heat required High-temperature applications — exhaust manifold studs, engine components, hot environments 277 Red Very High M20–M36+ 150°C Heat required Very large fasteners — maximum breakaway torque for flanges, heavy plant, large structural bolts 290 Green Medium M6–M20 150°C Yes — hand tools Wicking grade — post-assembly on pre-assembled or production-line fasteners; medium strength Loctite 242 vs 243 — What Changed? Loctite 243 is the current-generation replacement for 242. Both are medium-strength blue threadlockers for M6–M20 fasteners, and both develop the same cured strength on clean, degreased steel. The key improvement in 243 is better tolerance to light oil contamination on threads. In a workshop environment where threads are occasionally oily, 243 cures reliably where 242 may underperform. If you have 242 on the shelf, use it — it is equivalent to 243 on clean surfaces. For new stock, specify 243. Loctite 243 vs 263 — The Most Important Distinction This is the most common and consequential selection decision. The choice is simple: will this fastener ever need to be removed? Use 243 (blue) when the fastener may need to be removed for service, adjustment or replacement. Under vibration, 243 provides equivalent security to red — it will not self-loosen. But a standard spanner or socket applied with normal force will break the bond. This is the correct grade for brake caliper bolts, suspension components, machinery access panels, and any fastener in the service path. Use 263 or 271 (red) when the assembly is permanent — a structural joint, a stud that will never be pulled, or a high-vibration application where even low probability of movement is unacceptable. These grades require heating to 250°C before the fastener can be turned. Using red on a service fastener, or on a small bolt where that heat cannot be applied safely, is the most common Loctite misapplication on the workshop floor. Threadlocker Application Selection Guide Application Recommended Grade Reason Small adjustment screws, grub screws, M1.4–M6 222 (Purple) Low strength only — blue or red on small threads risks stripping or irreversible locking General fasteners requiring future service access, M6–M20 243 (Blue) Medium strength, hand-tool removable, the standard industrial choice Brake caliper bolts 243 (Blue) Service access required; OEM specification for most passenger and light commercial vehicles Wheel spacer bolts 243 (Blue) Vibration resistance with removability for tyre changes and wheel service Bicycle and bike component bolts 222 (Purple) Critical — titanium and aluminium threads cannot handle medium or high strength; purple only Flywheel bolts, ring gear bolts 263 or 271 (Red) Permanent structural joint; high vibration; rarely or never removed in service life Exhaust manifold studs, turbo bolts 272 (Red) High-strength with 230°C continuous service temperature — the only threadlocker rated for exhaust temperatures Pre-assembled joints — wicking application 290 (Green, medium) or 270 (Green, high) Low viscosity penetrates assembled threads via capillary action — apply externally after assembly Large structural fasteners M20 and above 277 (Red) Maximum breakaway torque for large thread engagement in heavy plant and structural applications Stainless steel fasteners into stainless 243 + Loctite 7649 Activator N Passive metal — requires activator for reliable cure; see surface preparation section below Stainless Steel, Aluminium and Other Passive Metals Loctite anaerobic products cure by reacting with the metal ions present in the substrate. Passive metals — stainless steel, aluminium, titanium, zinc plating, cadmium plating — have an oxide layer that slows or prevents this reaction. On stainless-to-stainless assemblies without treatment, cure may be incomplete, slow (days rather than hours), or fail entirely in cold conditions. The solution is Loctite 7649 Activator N: apply a thin coat to one mating surface, allow 30–60 seconds to dry, then apply the Loctite threadlocker to the other surface and assemble normally. The activator overcomes the passive layer and initiates rapid, complete cure. This step is not optional on stainless — it is the difference between a joint that works and one that fails at the worst moment. → Full guide: Loctite Threadlocker Guide — the complete grade-by-grade breakdown, decision framework and FAQs. Loctite Thread Sealants: Pipe, Hydraulic and Gas Applications Thread sealants seal tapered and parallel pipe threads against leakage of fluids and gases under pressure. They are a distinct product family from threadlockers — they are formulated for sealing pipe thread profiles (BSP, NPT, metric parallel), not for retaining standard bolts and fasteners. Product Type Max Pressure Max Temp Potable Water Best For Loctite 55 Sealing cord (PTFE alternative) 80 bar (gas) / 100 bar (liquid) −50°C to +130°C Yes — NSF 61 certified Gas, water, hydraulic; plastic and metal threads; instant pressure resistance on assembly Loctite 542 Anaerobic liquid 350 bar −65°C to +150°C No Fine metal hydraulic threads — instrumentation fittings, precision pneumatic connections Loctite 567 Anaerobic liquid 690 bar −65°C to +150°C No Metal pipe threads — hydraulic, pneumatic, fuel and oil systems; fine thread forms Loctite 577 Anaerobic liquid 400 bar −55°C to +150°C No Coarser BSP and NPT metal pipe threads — compressed air, water, oil and gas plumbing Loctite 55 — The PTFE Thread Seal Alternative Loctite 55 is not an anaerobic liquid — it is a continuous-filament sealing cord wound around threads by hand, replacing PTFE tape. Wound clockwise around the male thread (three to five turns for most fittings), it creates an immediate, compliant seal that develops full holding strength as the fitting is tightened. Its key advantages over PTFE tape: it can be hand-tightened to immediate pressure resistance with no cure wait; it works reliably on both metal and plastic fittings; it does not shred or delaminate into pipework; and it can be repositioned slightly after assembly if alignment is needed. Most importantly for Australian trade and construction applications, Loctite 55 is NSF 61 certified for potable water — it is the correct Loctite product for drinking water connections. It is also approved for gas service and is used on residential and commercial gas fittings where threaded connections are required. Loctite 567 vs 577 — Which Anaerobic Thread Sealant? Both 567 and 577 are anaerobic liquids that seal metal pipe threads. The difference is viscosity and thread form. Loctite 567 is lower viscosity — it wicks easily into fine hydraulic and pneumatic thread forms (SAE, metric fine), making it the correct choice for instrument fittings, hydraulic block connections and precision pneumatic assemblies where thread tolerances are tight. Loctite 577 is higher viscosity — it stays in place on coarser BSP and NPT threads during assembly, making it the standard choice for compressed air systems, water fittings and general industrial plumbing. If in doubt on a BSP fitting, use 577. If connecting hydraulic instrument tubing or fine metric threads, use 567. For cure times, fluid compatibility, passive metal guidance and a full application guide, see our Loctite 577 Thread Sealant Guide. → Full guide: Loctite Thread Sealant Guide — media compatibility, pressure ratings and application steps across the full range. Loctite Retaining Compounds: Bearing and Cylindrical Assembly Retaining compounds bond cylindrical assemblies — shaft-to-bearing, shaft-to-hub, pin-to-bore — by filling the microscopic clearance between components and polymerising into a rigid, load-bearing joint. They are used to augment or replace interference fits, to prevent fretting corrosion in light-clearance assemblies, and to salvage worn bores where a bearing has become loose in its housing. The two critical selection variables are the radial clearance between the mating components and the strength required. Using a product with a maximum clearance smaller than the actual gap will result in incomplete fill and significantly reduced bond strength. Grade Strength Max Clearance Max Temp Re-assemble? Best For 609 Low 0.10 mm 150°C Yes — press or hand Light-duty retention, small close-tolerance assemblies requiring re-use 638 High 0.15 mm 150°C With press or puller Close-tolerance bearing retention — maximum strength where fit is tight 641 Medium 0.25 mm 150°C Yes — press or puller Standard bearing and bushing retention — strength with serviceability 648 Maximum 0.15 mm 175°C Effectively no Permanent high-temperature assemblies where disassembly is never required 660 High 0.50 mm 150°C With press or puller Worn bore salvage — fills large clearances in worn housings and shafts 680 High 0.35 mm 150°C With press or puller General-purpose medium-to-large clearance bearing retention Choosing Between 638, 641 and 648 For new bearings in a correctly toleranced housing, 641 is the default choice. Medium strength, 0.25 mm maximum clearance, and removable with a standard bearing puller or hydraulic press — this covers the vast majority of bearing retention applications in industrial and agricultural equipment. Use 638 when the fit is very close and maximum strength is required. In a tight housing where interference fit alone is nearly sufficient, 638 augments the fit to create an exceptionally strong, permanent joint. Note that 638 in a tight bore with a light press fit is very difficult to disassemble — treat it as semi-permanent. Use 648 only when the assembly will never be disassembled and operating temperatures exceed 150°C. Loctite 648 is the most thermally resistant retaining compound and produces the highest bond strength in the range — but the joint is effectively destroyed on any attempt at disassembly. Reserve it for permanent high-temperature applications such as motor shaft assemblies in hot environments. For worn bores where the bearing is loose in the housing (clearance beyond 0.25 mm), use 660. It fills gaps up to 0.5 mm, locks the bearing in the oversized bore, and restores the housing to service without machining. This is the most commonly used retaining compound in field service and overhaul environments where worn machinery is being returned to service. Browse AIMS Industrial's full Loctite retaining compound range including 638, 641, 648 and 660. → Full guide: Loctite Retaining Compound Guide — diametral clearance selection, installation and bearing removal. Loctite Anti-Seize Anti-seize does the opposite of a threadlocker. Where threadlockers lock fasteners in place by filling the thread void, anti-seize prevents fasteners from seizing, galling and corroding in ways that make them impossible to remove. Never apply both to the same fastener. Loctite C5-A Copper Anti-Seize is the industrial standard — a copper-based paste rated to 980°C. Correct applications include stainless-on-stainless assemblies where galling is a risk (anti-seize is far more effective than threadlocker at preventing galling), exhaust bolts and manifold studs subject to repeated heat cycling, fasteners in corrosive environments such as marine, chemical plant and agricultural equipment, and any assembly where long-term disassembly is essential. Important torque note: Anti-seize reduces the friction coefficient of threads. If torquing to a manufacturer specification designed for dry or lightly oiled threads, the torque value must be reduced when anti-seize is applied — typically by 20 to 25%. Applying full dry-thread torque with anti-seize present will over-stress the fastener. Surface Preparation: The Critical Step Loctite anaerobics cure by reacting with metal ions in the substrate. Surface contamination — oil, grease, coolant, cutting fluid, rust preventative — inhibits this reaction and reduces cured strength. Inadequate surface preparation is the primary cause of Loctite application failures. Standard preparation for all Loctite anaerobic products: Degrease both mating surfaces with Loctite 7063 cleaning solvent or isopropyl alcohol. Apply solvent, agitate if necessary to remove oil film, and allow to evaporate fully — do not assemble onto wet surfaces. On threaded fasteners, apply solvent to the bore threads and the bolt shank and allow to dry before applying Loctite. For passive metals (stainless steel, aluminium, titanium, zinc, cadmium plating): Apply Loctite 7649 Activator N to one surface and allow 30–60 seconds to dry before applying the Loctite product to the other surface. This step is not optional — without activator on stainless steel, cure is unreliable, particularly at temperatures below 15°C. The activator is low-cost and eliminates a significant failure mode. Cure Time Reference Product Type Grade Handling Strength (steel, 22°C) Full Cure Low-strength threadlocker 222 10 minutes 24 hours Medium-strength threadlocker 242, 243 10 minutes 24 hours High-strength threadlocker 262, 263, 271 20 minutes 24 hours High-temp threadlocker 272 20 minutes 24 hours (full high-temp rating requires post-cure at 120°C for 30 min) Wicking threadlocker 270, 290 15 minutes 24 hours Standard retaining compound 638, 641 10–15 minutes (fixture) 24 hours High-temp retaining compound 648 15 minutes (fixture) 24 hours (post-cure at 120°C recommended for full performance) Thread sealant 567, 577 Immediate pressure resistance 24 hours full cure Cold temperature note: Below 10°C, all cure times extend significantly — allow 48 to 72 hours for full cure in cold conditions. Cure can be accelerated to near-full strength by warming the assembled joint to 80°C for 30 minutes. On passive metals without activator, add 50% to all cure time estimates. Removing Loctite Threadlocker The correct removal method for any Loctite threadlocker — blue or red — is heat. Apply a heat gun or torch to bring the joint to approximately 250°C, then apply torque to the fastener immediately while the joint is still hot. The cured Loctite softens above this temperature and releases. Do not heat the joint and then allow it to cool before attempting removal — the Loctite will re-harden and lock the fastener again. Blue (medium strength) threadlocker: Heat to 250°C is effective but not always required. Strong, steady hand-tool force will release most blue-locked joints without heat. If a blue-locked fastener resists standard hand tool force, apply heat before increasing effort — forcing a locked fastener with an extension bar risks breaking the bolt or stripping the thread rather than releasing the Loctite. Red (high strength) threadlocker: Heat is not optional. Do not attempt to remove a red-locked fastener with hand tools alone — the breakaway torque exceeds what hand tools can safely apply on most bolt sizes. Apply direct heat to the joint, apply torque immediately while hot, and repeat the heat-and-torque cycle if the fastener does not break free on the first attempt. Aluminium and composite components: Use a heat gun rather than a torch to avoid warping or heat-damaging the surrounding material. Apply heat gradually and test the fastener for movement frequently rather than applying maximum heat in one go. If heat risks damaging adjacent components, soak the joint overnight with a penetrating oil to assist, then apply minimum heat to break free. After removal: Clean old Loctite from threads with a wire brush and solvent before re-applying fresh product. Do not re-apply new Loctite over hardened residue — the cured material does not dissolve or re-activate. Loctite Instant Adhesives: 401, 406 and the Cyanoacrylate Range Loctite's cyanoacrylate (CA) range — commonly called instant adhesives or superglue — are chemically distinct from the anaerobic products above. They cure by reacting with surface moisture rather than requiring the absence of oxygen or metal ions, and they are not suitable for thread locking, pipe sealing or cylindrical retention. Loctite 401 is the standard-viscosity general-purpose CA adhesive. It bonds metal, rubber, rigid plastics and most hard materials in seconds. For most instant adhesive applications in a trade or industrial workshop, 401 is the correct starting choice. See our Loctite 401 complete guide for full substrate compatibility, cure times and storage information. Loctite 406 is formulated for difficult substrates — polyolefin plastics (polyethylene, polypropylene), rubbers and elastomers that standard CA adhesives cannot reliably bond. It contains a surface-insensitive primer agent that promotes adhesion on low-energy surfaces. For bonding rubber seals to metal housings, or joining PP and PE components, 406 is significantly more reliable than 401. Loctite 454 is a gel-form CA that stays in position on vertical surfaces and fills small gaps — the correct choice where a liquid adhesive would run before the joint is closed, or where mating surfaces are slightly rough or porous. Loctite 480 is a rubber-toughened CA for applications requiring a flexible, impact-resistant bond — rubber-to-rubber and rubber-to-metal joints where a rigid brittle bond would crack under flexing. Loctite Product Equivalents The most frequently searched Loctite equivalent products come from the Permatex range. The approximate equivalents for the main industrial grades are: Loctite Grade Permatex Equivalent Notes 222 — Purple, low strength Permatex 24010 Functionally equivalent; verify application torque values independently 243 — Blue, medium strength Permatex 24200 Direct equivalent for general-purpose medium-strength applications 271 / 263 — Red, high strength Permatex 27200 High-strength equivalent; verify temperature ratings for your specific application When substituting between brands, always confirm that the equivalent grade meets your specific temperature, gap clearance and torque requirements — equivalent strength does not guarantee identical performance in all conditions. Lock it. Seal it. Trust it. Related AIMS Selectors This selector pairs with AIMS's other fastener & adhesive guides: Loctite 222 Guide — purple low-strength threadlocker deep-dive. Loctite 243 Guide — medium-strength workshop default. Loctite 401 Guide — instant adhesive (cyanoacrylate). Loctite 577 Guide — medium-strength thread sealant. Loctite Threadlocker Guide — full threadlocker category guide. Loctite Retaining Compound Guide — bearing installation and grade selection. Loctite Thread Sealant Guide — full thread sealant category guide. Thread Locking & Sealing Guide — anaerobic chemistry + application technique. Industrial Adhesive Types Guide — broader adhesives hub: epoxy, RTV, structural. How to Remove Stuck Bolts & Nuts — when Loctite has done its job too well. Metric Bolt Torque Chart — torque values per grade and size. Or browse the full Loctite range, threadlockers, retaining compounds, gasket sealants, thread sealants, activators, cleaners & primers. Next-day Australia-wide dispatch from our Milperra warehouse. Shop the full Loctite range — threadlockers, retaining compounds & sealants From Loctite 222 low-strength to 263 high-strength threadlocker, 641 retaining compound, and 55 pipe sealant — AIMS Industrial is an authorised Loctite stockist with the full range available for fast Australia-wide dispatch. Shop Loctite at AIMS Talk to a specialist Frequently Asked Questions What is the best Loctite threadlocker for small screws?Loctite 222 (purple) is the only correct choice for screws up to M6. Small threads — grub screws, electronics fasteners, instrument hardware, adjustment screws — do not have sufficient thread engagement to handle the breakaway torque of medium or high-strength threadlocker. Applying blue (243) to an M3 or M4 grub screw will very likely make it impossible to remove without damaging the threads or the housing. Use purple (222) for anything M6 and smaller, without exception. What is the difference between blue and red Loctite?Blue Loctite (243) is medium strength and removable with hand tools — the standard choice for fasteners that need to be serviced, adjusted or replaced in the future. It will not self-loosen under vibration, but a spanner or socket applied with normal force will release it. Red Loctite (263, 271) is high strength and permanently locks the fastener — it requires heating the joint to 250°C before any torque will release it. The correct rule: if the fastener may ever need to come off, use blue. If it is a truly permanent structural joint, use red. Which Loctite threadlocker is the strongest?In the standard threadlocker range, Loctite 277 (red) has the highest breakaway torque and is formulated for large-diameter fasteners (M20–M36+). For the M6–M36 range, Loctite 263 and 271 provide effectively equivalent maximum strength for most applications. Loctite 648 is the maximum-strength retaining compound for cylindrical assemblies, though it serves a different function. For most industrial work, 271 or 263 provide more than sufficient permanent locking strength. Can Loctite cure on oily or contaminated threads?Standard threadlocker grades (242, 263) require clean, degreased surfaces for full strength development. Loctite 243 is formulated with improved oil tolerance and will cure acceptably on lightly oiled threads. On heavily contaminated or wet surfaces, no anaerobic product will achieve full strength — clean first. For post-assembly applications where disassembly is not practical, a wicking grade (290 for medium strength, 270 for high strength) applied to the external thread after cleaning the exposed surface will penetrate and lock the joint, but ultimate strength depends on the cleanliness of the thread interface. Can Loctite threadlocker be used on plastic threads?Anaerobic threadlockers require metal ions to cure and are formulated for metal-to-metal contact. On plastic threads, cure is unreliable, strength is substantially reduced, and certain Loctite formulations can stress-crack specific plastics — notably polystyrene and polycarbonate. For sealing plastic pipe fittings, use Loctite 55 sealing cord — it works on plastic threads without chemical incompatibility risk. For retention on plastic fasteners, mechanical solutions (nylon insert nuts, serrated flange fasteners) are more reliable than chemical threadlockers. Are Loctite thread sealants suitable for potable water pipes?Loctite 55 sealing cord is NSF 61 certified for potable water and is the correct Loctite product for any fitting in contact with drinking water. The anaerobic liquid sealants — 567 and 577 — are not NSF 61 certified and must not be used on potable water connections. For gas pipe connections (residential and commercial), Loctite 55 is also approved and is used on threaded gas fittings in Australia. It replaces PTFE tape in these applications with no need for cure time before pressurisation. How long does Loctite threadlocker take to fully cure?On clean steel at 22°C, most grades reach handling strength in 10–20 minutes — sufficient to torque the fastener and move the assembly without disturbing the joint. Full cure takes 24 hours. Below 10°C, cure times extend significantly — allow 48 to 72 hours at low temperatures. Cure can be accelerated by heating the assembled joint to 80°C for 30 minutes. On passive metals (stainless steel, aluminium) without activator, add at least 50% to all cure times and treat handling strength with caution. How do I remove a bolt locked with red Loctite threadlocker?Heat the joint directly to approximately 250°C using a heat gun or butane torch, then apply torque to the fastener immediately while it is still hot. The cured Loctite softens at this temperature and allows the fastener to turn. Do not heat the joint and then allow it to cool before trying — the Loctite re-hardens on cooling. If the fastener does not release on the first attempt, re-apply heat and try again. Never use an impact wrench on a locked fastener without heating first — the risk of shearing the bolt is significantly higher than the effort of applying heat. What is the difference between Loctite 567 and 577 thread sealant?Both are anaerobic liquids for sealing metal pipe threads. Loctite 567 is lower viscosity — it wicks easily into fine thread forms (SAE hydraulic fittings, metric fine, instrument connections) and is the correct choice for hydraulic and pneumatic precision connections. Loctite 577 is higher viscosity and stays in position on coarser BSP and NPT pipe threads during assembly. For most compressed air, water and gas plumbing on BSP fittings, 577 is the standard choice. For hydraulic block connections and instrument fittings with fine thread forms, use 567. See our full Loctite 577 Thread Sealant Guide for the complete application reference. Which Loctite retaining compound should I use for bearing retention?For standard bearing retention with normal bore clearance, Loctite 641 is the default choice — medium strength, handles clearances up to 0.25 mm, and the bearing can be removed with a press or standard puller for service. Use Loctite 638 for close-tolerance fits requiring maximum bond strength. Use Loctite 660 for worn bores with clearance above 0.25 mm — it fills gaps up to 0.5 mm and locks a loose bearing in an oversized housing without machining. Reserve Loctite 648 for permanent high-temperature assemblies that will never be disassembled. What is the difference between Loctite 401 and 406?Loctite 401 is a standard-viscosity cyanoacrylate (instant adhesive) for general bonding of metal, rubber and most rigid plastics. Loctite 406 is formulated specifically for difficult low-energy substrates — polyolefin plastics (polyethylene, polypropylene) and elastomers that standard CA adhesives cannot reliably bond. If you're bonding rubber gaskets, polypropylene fittings or PE components, 406 is the correct grade. For metal-to-metal, glass-to-metal or general rigid bonding, 401 is sufficient. The 406 premium is only justified where the substrate is a known adhesive-resistant plastic or rubber. For metric bolt diameter, pitch and head dimensions from M3 to M24, see our Metric Bolt Size Guide. People Also Ask — Loctite Grade Selection Q: What is the difference between Loctite 243 and Loctite 263? Loctite 243 is a medium-strength threadlocker removable with hand tools after cure — suitable for most fasteners M6 to M20 where future disassembly is expected. Loctite 263 is high-strength and permanently bonds fasteners; removal requires heat above 250°C. Use 243 for routine maintenance, 263 where vibration risk is severe and disassembly is not planned. Q: How long does Loctite threadlocker take to cure? Loctite 243 achieves handling strength in approximately 10 minutes on steel at 22°C. Full chemical cure takes 24 hours. Cure is slower on passive metals (stainless steel, zinc) and in cold conditions — allow extra time before applying service loads. Activator SF 7649 speeds cure on passive metals. Q: Can you use Loctite on aluminium threads? Yes. Loctite anaerobic threadlockers including Loctite 222, 243, and 263 are compatible with aluminium. Aluminium is a passive metal, so cure is slower than on steel. Apply Loctite Activator SF 7649 to one thread surface first to achieve reliable cure speed and strength on aluminium fasteners. Q: What Loctite grade is best for stainless steel fasteners? Loctite 243 medium-strength or Loctite 263 high-strength both work on stainless steel, but stainless is a passive metal — always apply Activator SF 7649 first. For stainless fasteners in food or hygienic environments, Loctite 2400 is a water-washable, low-odour alternative approved for incidental food contact. Q: What is Loctite 577 used for? Loctite 577 is a medium-strength thread sealant for parallel (BSP) threads used in hydraulic and pneumatic systems. It seals metal-to-metal pipe threads and fitting connections against fluid and gas leakage up to 150 bar, while remaining removable with hand tools for maintenance. Not a threadlocker — designed specifically for fluid-system thread sealing. Looking for anti-vibration mounts? Our anti-vibration mounts range covers the common sizes and brands.
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Tap Drill Size Chart: Metric & Imperial Thread Sizes
Tap drill size is the diameter of the pilot hole drilled before threading. The rule: drill diameter = thread outer diameter − thread pitch. For M8 × 1.25 coarse, the tap drill is 6.8mm. For 1/4" BSP, it's 11.8mm. The compact reference below covers the most-used metric coarse sizes; full metric fine, BSP, UNC and UNF charts are further down. (If you are looking for the Sutton Tap & Drill Chart PDF, click here.) Quick answer — most common sizes Metric coarse: M3 = 2.5mm · M4 = 3.3mm · M5 = 4.2mm · M6 = 5.0mm · M8 = 6.8mm · M10 = 8.5mm · M12 = 10.2mm · M14 = 12.0mm · M16 = 14.0mm · M20 = 17.5mm BSP: 1/8" = 8.8mm · 1/4" = 11.8mm · 3/8" = 15.0mm · 1/2" = 18.6mm UNC: 1/4"-20 = 5.1mm · 5/16"-18 = 6.9mm · 3/8"-16 = 7.9mm · 1/2"-13 = 10.7mm Formula: tap drill (mm) = thread OD − pitch. Full charts below. For more engineering reference charts and selection tables, see our Engineering Reference Charts hub — covering fasteners, bearings, lubrication, measuring, welding and Australian standards. Tap & Drill Bit Selector — Most-Asked Metric Sizes This page is a working selector tool — not just a reference. Use it to get the right tap and drill into your hand in one click. The 10 most-asked metric thread sizes at AIMS are below. For less common sizes, scroll to the full charts further down (use the jump-nav below). How to use: 1. Find your thread size 2. See the matching tap drill diameter 3. Click Buy Tap or Buy Drill — sized to match M3 Tap drill 2.5 mm Buy tap → Buy drill → M4 Tap drill 3.3 mm Buy tap → Buy drill → M5 Tap drill 4.2 mm Buy tap → Buy drill → M6 Tap drill 5.0 mm Buy tap → Buy drill → M8 Tap drill 6.8 mm Buy tap → Buy drill → M10 Tap drill 8.5 mm Buy tap → Buy drill → M12 Tap drill 10.2 mm Buy tap → Buy drill → M14 Tap drill 12.0 mm Buy tap → Buy drill → M16 Tap drill 14.0 mm Buy tap → Buy drill → M20 Tap drill 17.5 mm Buy tap → Buy drill → Default recommendation: Sutton Spiral Point HSS taps and Sutton D101 Silver Bullet HSS jobber drills — the workshop standard for mild steel. AIMS also stocks Bordo and P&N as alternates. For stainless steel or hardened steel, switch to cobalt drill bits + cobalt taps (see the "By Material" section below). Need help? Call us on (02) 9773 0122. Jump to: Metric Coarse Metric Fine BSP UNC UNF By Material Related Selectors Tap Drill Size Chart — Metric Coarse Quick Reference The most frequently used metric coarse thread sizes and their tap drill diameters: Thread Tap Drill (mm) Thread Tap Drill (mm) M3 2.5 M12 10.2 M4 3.3 M14 12.0 M5 4.2 M16 14.0 M6 5.0 M18 15.5 M8 6.8 M20 17.5 M10 8.5 M24 21.0 How to Use This Chart Tap drill size refers to the diameter of the hole you drill before running a tap through it. The hole must be smaller than the thread's outer diameter, leaving enough material for the tap to cut the thread profile. Too large and the thread is shallow and weak. Too small and you risk breaking the tap. As a general rule, tap drill size = thread outer diameter − thread pitch. This gives approximately 75% thread engagement, which is standard for most applications. For softer materials or where tap breakage is a concern, go slightly larger. For maximum thread strength in hard materials, go slightly smaller. By accurately matching the tap size to the drill size and choosing the right tap for the job, you can achieve optimal results in your thread cutting operations. Where a bolt or screw passes through a hole rather than being tapped into it, you need a clearance hole instead — sized so the fastener slides through freely rather than cutting a thread. The metric tables below include a Clearance Hole (mm) column for this, based on the ISO 273 normal (medium) fit for the diameters most commonly used in through-bolt assembly. A dash (—) marks sizes that fall outside the standard clearance-hole table — generally uncommon "second choice" diameters rarely used for through-bolt work. Metric Coarse Tap Drill Size Chart Metric coarse is the standard thread series for most bolts, screws and tapped holes in general engineering. Pitch is expressed in millimetres — a lower number means finer threads. These are the sizes you'll use for the vast majority of metric tapping work. Need help finding your size? Call AIMS on (02) 9773 0122 — the team can confirm stock and pick the right tap type for your job. Or browse all metric coarse taps and jobber drill bits. Thread Size Pitch (mm) Tap Drill (mm) Tap Drill (inch approx.) Clearance Hole (mm) M1 0.25 0.75 --- — M1.2 0.25 0.95 --- — M1.4 0.30 1.10 --- — M1.6 0.35 1.25 --- 1.8 M1.8 0.35 1.45 --- — M2 0.40 1.60 1/16" 2.4 M2.5 0.45 2.05 5/64" 2.9 M3 0.50 2.50 3/32" 3.4 M3.5 0.60 2.90 7/64" — M4 0.70 3.30 1/8" 4.5 M5 0.80 4.20 11/64" 5.5 M6 1.00 5.00 13/64" 6.6 M7 1.00 6.00 15/64" — M8 1.25 6.80 17/64" 9.0 M10 1.50 8.50 21/64" 11.0 M12 1.75 10.20 25/64" 13.5 M14 2.00 12.00 15/32" 15.5 M16 2.00 14.00 35/64" 17.5 M18 2.50 15.50 39/64" — M20 2.50 17.50 11/16" 22.0 M22 2.50 19.50 49/64" — M24 3.00 21.00 53/64" 26.0 M27 3.00 24.00 15/16" — M30 3.50 26.50 1-3/64" 33.0 M33 3.50 29.50 1-5/32" — M36 4.00 32.00 1-17/64" 39.0 M39 4.00 35.00 1-3/8" — M42 4.50 37.50 1-15/32" 45.0 M45 4.50 40.50 1-19/32" — M48 5.00 43.00 1-11/16" 52.0 Metric Fine Tap Drill Size Chart Metric fine threads are used where vibration resistance, fine adjustment, or higher tensile strength is required — common in automotive, aerospace, and precision engineering applications. Multiple pitches exist per diameter; confirm your pitch before selecting the drill. Need help finding your size? Call AIMS on (02) 9773 0122 — the team can confirm stock and pick the right tap type for your job. Or browse all metric fine taps and jobber drill bits. Thread Size Pitch (mm) Tap Drill (mm) Clearance Hole (mm) M1 × 0.2 0.20 0.80 — M1.2 × 0.2 0.20 1.00 — M1.4 × 0.2 0.20 1.20 — M1.6 × 0.2 0.20 1.40 1.8 M2 × 0.25 0.25 1.75 2.4 M2.5 × 0.35 0.35 2.15 2.9 M3 × 0.35 0.35 2.65 3.4 M3.5 × 0.35 0.35 3.15 — M4 × 0.5 0.50 3.50 4.5 M5 × 0.5 0.50 4.50 5.5 M6 × 0.75 0.75 5.25 6.6 M7 × 0.75 0.75 6.25 — M8 × 0.75 0.75 7.25 9.0 M8 × 1.0 1.00 7.00 9.0 M10 × 0.75 0.75 9.25 11.0 M10 × 1.0 1.00 9.00 11.0 M10 × 1.25 1.25 8.75 11.0 M12 × 1.0 1.00 11.00 13.5 M12 × 1.25 1.25 10.75 13.5 M12 × 1.5 1.50 10.50 13.5 M14 × 1.0 1.00 13.00 15.5 M14 × 1.25 1.25 12.75 15.5 M14 × 1.5 1.50 12.50 15.5 M16 × 1.0 1.00 15.00 17.5 M16 × 1.5 1.50 14.50 17.5 M18 × 1.5 1.50 16.50 — M18 × 2.0 2.00 16.00 — M20 × 1.5 1.50 18.50 22.0 M20 × 2.0 2.00 18.00 22.0 M22 × 1.5 1.50 20.50 — M22 × 2.0 2.00 20.00 — M24 × 1.5 1.50 22.50 26.0 M24 × 2.0 2.00 22.00 26.0 M27 × 2.0 2.00 25.00 — M30 × 1.5 1.50 28.50 33.0 M30 × 2.0 2.00 28.00 33.0 M33 × 2.0 2.00 31.00 — M36 × 1.5 1.50 34.50 39.0 M36 × 3.0 3.00 33.00 39.0 Tap & Drill Selection by Material The right tap drill diameter is one half of the job. The other half is choosing tap and drill geometry that match your workpiece material. This is where most beginner tappers come unstuck — wrong tap type for the material means broken taps, oversized threads, or torn surface finishes. Here's what the AIMS workshop crew reaches for, by material: Mild steel (most common workshop material) Drill: Sutton D101 Silver Bullet HSS jobber (bright finish, 118° point) for occasional tapping. Sutton D102 Blue Bullet HSS (steam-oxide finish) for production tapping — the steam oxide finish helps swarf release on steel. Tap: Sutton Spiral Point HSS taps (T1xx series) for through holes — fastest, swarf pushes ahead of the tap. For blind holes, switch to Spiral Flute (T2xx series) so swarf evacuates upward and out of the hole. Lubricant: Tap Magic Original or any general-purpose cutting fluid. Stainless steel (304, 316, 17-4 PH) Drill: Cobalt drill bit — Sutton D108 or D109 cobalt jobber. The 5% to 8% cobalt content lets the drill stay sharp through stainless's work-hardening tendency. HSS bright drills will glaze the hole surface, work-harden the steel, and snap on the next pass. Tap: Cobalt steel tap — Sutton Spiral Flute Premium HSS Cobalt or Sutton Premium HSS Tinite-coated. The cobalt grade survives the harder material; cheap HSS chrome taps will snap on the first thread. Lubricant: Tap Magic for Stainless Steel — specifically formulated. Don't skimp here. Aluminium, brass, copper, plastics Drill: Standard HSS Sutton D101 Silver Bullet is fine. Some users prefer a slightly higher helix angle drill for softer non-ferrous materials — Sutton's 130° or 140° point geometry options. Tap: Spiral Flute tap is excellent here — long stringy chips need to evacuate cleanly, and spiral flute pulls them up and out. Avoid spiral point in soft aluminium (it bunches chips inside the hole). Lubricant: Tap Magic Aluminium variant — formulated to prevent the gummy build-up that aluminium causes on standard cutting fluids. Cast iron (grey, ductile, malleable) Drill: HSS Sutton D102 Blue Bullet (steam-oxide). Cast iron is brittle and abrasive — the steam oxide finish helps prolong drill life. Tap: Straight Flute tap (T4xx series) or hand tap. Cast iron breaks into powder rather than chips, so spiral evacuation isn't needed — straight flute is more rigid and handles the abrasiveness better. Lubricant: Generally tapped DRY — no cutting fluid needed for cast iron because chips are powder, not strings. Hardened steel (above ~30 HRC) For anything above mild steel hardness — pre-hardened tool steels, heat-treated parts, hardfaced surfaces — call AIMS before you start drilling. Solid carbide drills + thread mills are the right answer here, not standard taps. Contact us or call (02) 9773 0122 — we'll save you broken taps and damaged workpieces. The AIMS workshop rule: The right cutting fluid is worth more than the right tap. Even a premium Sutton tap will fail prematurely if you're tapping stainless without proper lubrication. Tap Magic cutting fluid guide covers which formulation matches your material. BSP Tap Drill Size Chart (British Standard Pipe) BSP threads are used on pipe fittings, hydraulic connections, and pneumatic systems throughout Australia and the UK. Sizes refer to the nominal bore of the pipe — not the actual thread diameter, which is always larger. BSPP (parallel) and BSPT (taper) share the same thread form and the same tap drill size. Need help finding your size? Call AIMS on (02) 9773 0122 — the team can confirm stock and pick the right tap type for your job. Or browse all BSP taps and jobber drill bits. Nominal Size TPI Tap Drill (mm) Tap Drill (inch) 1/16" BSP 28 6.6 0.261" 1/8" BSP 28 8.8 0.347" 1/4" BSP 19 11.8 0.465" 3/8" BSP 19 15.0 0.590" 1/2" BSP 14 18.6 0.733" 3/4" BSP 14 24.3 0.956" 1" BSP 11 30.5 1.200" 1¼" BSP 11 39.2 1.544" 1½" BSP 11 45.1 1.776" 2" BSP 11 57.0 2.245" 2½" BSP 11 72.6 2.858" 3" BSP 11 87.8 3.457" The 1/4" BSP tap drill size (11.8mm) is one of the most commonly referenced in Australian trade and industrial work. If you're unsure whether your fitting is BSPP or BSPT, the tap drill size is the same for both — the distinction only matters when selecting the tap itself. UNC Tap Drill Size Chart (Unified National Coarse) UNC is the standard US coarse thread series. Common in imported machinery, agricultural equipment, and items manufactured to American standards. Identified by thread count in threads per inch (TPI). Need help finding your size? Call AIMS on (02) 9773 0122 — the team can confirm stock and pick the right tap type for your job. Or browse all UNC taps and jobber drill bits. Thread TPI Tap Drill (mm) Tap Drill (fractional inch) #4-40 40 2.4 3/32" #5-40 40 2.65 --- #6-32 32 2.8 7/64" #8-32 32 3.5 9/64" #10-24 24 3.9 5/32" 1/4"-20 20 5.1 13/64" 5/16"-18 18 6.9 17/64" 3/8"-16 16 7.9 5/16" 7/16"-14 14 9.4 3/8" 1/2"-13 13 10.7 27/64" 9/16"-12 12 12.3 31/64" 5/8"-11 11 13.5 17/32" 3/4"-10 10 16.7 21/32" 7/8"-9 9 19.4 49/64" 1"-8 8 22.2 7/8" 1-1/8"-7 7 25.4 1" 1-1/4"-7 7 28.6 1-1/8" 1-3/8"-6 6 31.0 1-7/32" 1-1/2"-6 6 34.1 1-11/32" UNF Tap Drill Size Chart (Unified National Fine) UNF has a finer pitch than UNC — more threads per inch, higher tensile strength, and better vibration resistance. Used in aerospace, precision equipment, and anywhere a finer thread is specified. When in doubt, check the thread count: more threads per inch means UNF. Need help finding your size? Call AIMS on (02) 9773 0122 — the team can confirm stock and pick the right tap type for your job. Or browse all UNF taps and jobber drill bits. Thread TPI Tap Drill (mm) Tap Drill (fractional inch) #4-48 48 2.3 3/32" #6-40 40 2.9 7/64" #8-36 36 3.5 9/64" #10-32 32 3.8 9/64" 1/4"-28 28 5.6 7/32" 5/16"-24 24 6.9 17/64" 3/8"-24 24 8.5 21/64" 7/16"-20 20 9.9 25/64" 1/2"-20 20 11.5 29/64" 9/16"-18 18 13.1 33/64" 5/8"-18 18 14.7 37/64" 3/4"-16 16 17.5 11/16" 7/8"-14 14 20.6 13/16" 1"-12 12 23.4 59/64" 1-1/8"-12 12 26.6 1-3/64" 1-1/4"-12 12 29.8 1-3/16" 1-3/8"-12 12 33.0 1-5/16" 1-1/2"-12 12 36.5 1-7/16" Related AIMS Selectors & Guides This page sits at the centre of AIMS's threading and drilling tool cluster. The related selectors and selection guides below go deeper on the choices around it: Tap & Die Selection Guide — what tap type for which material, hole type, and machine Drill Bit Selection Guide — HSS vs cobalt vs carbide, jobber vs stub vs reduced shank Cutting Speeds & Feeds Reference — Vc and feed rate by material and tool type Cutting Tool Materials — HSS, cobalt, carbide, PCBN, PCD compared Cutting Tool Coatings — TiN, TiAlN, AlCrN, when each matters Cutting Tool Troubleshooting — broken taps, walking drills, poor finish, oversize holes Metric / Imperial / Gauge Conversion Master Chart — full drill bit + thread size cross-reference Thread Standards: BSP vs NPT vs UNC — identify the thread system you're dealing with Or browse the full taps range + jobber drill bits + cobalt drill bits — Sutton primary stock, Bordo and P&N alternates, specialty brands available for next-day Australia-wide dispatch from our Milperra warehouse.Frequently Asked Questions What drill size for M3 tap? For M3 coarse thread (0.5mm pitch), use a 2.5mm tap drill. For M3 fine (0.35mm pitch), use a 2.65mm drill. Formula: 3 − 0.5 = 2.5mm. What drill size for M4 tap? For M4 coarse thread (0.7mm pitch), use a 3.3mm tap drill. For M4 fine (0.5mm pitch), use a 3.5mm drill. Formula: 4 − 0.7 = 3.3mm. What drill size for M5 tap? For M5 coarse thread (0.8mm pitch), use a 4.2mm tap drill. For M5 fine (0.5mm pitch), use a 4.5mm drill. Formula: 5 − 0.8 = 4.2mm. What drill size for M6 tap? For M6 coarse thread (1.0mm pitch), use a 5.0mm tap drill. For M6 fine (0.75mm pitch), use a 5.25mm drill. Formula: 6 − 1.0 = 5.0mm. What drill size for M8 tap? For M8 coarse thread (1.25mm pitch), use a 6.8mm tap drill. For M8 fine (1.0mm pitch), use a 7.0mm drill. Formula: 8 − 1.25 = 6.75mm, rounded to 6.8mm. What drill size for M10 tap? For M10 coarse thread (1.5mm pitch), use an 8.5mm tap drill. For M10 fine (1.25mm pitch), use 8.75mm; for M10 fine (1.0mm pitch), use 9.0mm. Formula: 10 − 1.5 = 8.5mm. What drill size for M12 tap? For M12 coarse thread (1.75mm pitch), use a 10.2mm tap drill. For M12 fine (1.5mm pitch), use 10.5mm; for M12 fine (1.25mm pitch), use 10.75mm. Formula: 12 − 1.75 = 10.25mm, rounded to 10.2mm. What drill size for M14 tap? For M14 coarse thread (2.0mm pitch), use a 12.0mm tap drill. For M14 fine (1.5mm pitch), use 12.5mm. Formula: 14 − 2.0 = 12.0mm. What drill size for M16 tap? For M16 coarse thread (2.0mm pitch), use a 14.0mm tap drill. For M16 fine (1.5mm pitch), use 14.5mm. Formula: 16 − 2.0 = 14.0mm. What drill size for M20 tap? For M20 coarse thread (2.5mm pitch), use a 17.5mm tap drill. For M20 fine (2.0mm pitch), use 18.0mm; for M20 fine (1.5mm pitch), use 18.5mm. Formula: 20 − 2.5 = 17.5mm. What drill size for 1/4 inch BSP tap? The recommended tap drill for 1/4 inch BSP (19 TPI) is 11.8mm, or 0.465 inches. This applies to both BSPP (parallel) and BSPT (taper) threads — the tap drill is the same. What drill size for 1/8 inch NPT tap? The recommended tap drill for 1/8 inch NPT (27 TPI) is 8.6mm, or 21/64 inch. NPT is a tapered thread used on American pipe fittings — distinct from BSP. What drill size for 1/4 inch UNC tap? For 1/4-20 UNC, use a 5.1mm tap drill (13/64 inch). UNC has 20 threads per inch and is the standard US coarse thread. How do I calculate tap drill size for metric threads? Tap drill size (mm) equals thread diameter minus thread pitch. Example: M10 × 1.5 = 10 − 1.5 = 8.5mm. This gives approximately 75% thread engagement, which is standard for most applications. What is a tap drill size? A tap drill size is the diameter of the hole you drill before cutting a thread with a tap. It must be smaller than the thread's outer diameter so the tap has material to cut the thread profile into. What is the difference between BSPP and BSPT? BSPP (British Standard Pipe Parallel) has straight threads and seals with an O-ring or washer. BSPT (British Standard Pipe Taper) has a tapered thread that seals as it tightens. Both share the same tap drill size for a given nominal size, but BSPT taps are designed to cut a taper. If a tap breaks during the threading process, see our guide on how to remove a broken tap — covering all six removal methods from tap extractors through to EDM. Ready to tap? Shop our full range of taps, dies & threading tools From metric hand taps to imperial die sets — AIMS Industrial stocks threading tools for every standard, ready to ship Australia-wide. Browse taps Talk to a specialist For the tap type that matches your hole and material, see our Tap Types Explained guide. For choosing the right cutting fluid for your material, see our Tap Magic cutting fluid guide. Need to identify a thread standard? Our Thread Standards Guide covers BSP, NPT, UNC, UNF, BSW and metric with identification tips. People Also Ask — Tap Drill Size Chart: Metric & Imperial Thread Sizes Q: What drill size do I use for an M10 tap? For M10 × 1.5 coarse thread, use an 8.5 mm pilot drill. For M10 × 1.25 fine thread, use a 8.75 mm drill (often rounded to 9.0 mm in practice). Using the correct pilot hole is critical — too small risks tap breakage; too large produces insufficient thread engagement and weak joints. Q: What is the difference between a taper tap and a plug tap? A taper tap has a long chamfer (8–10 threads) that guides it into the hole gradually — best for starting threads in blind or through holes. A plug tap (4–5 thread chamfer) picks up where the taper left off and is the most common general-purpose tap. A bottoming tap has just 1–2 threads of chamfer for cutting threads to the very bottom of a blind hole. Q: What is the difference between BSP and NPT threads? BSP (British Standard Pipe) uses a 55° thread angle and is the standard for most Australian, British, and European hydraulic and pneumatic fittings. NPT (National Pipe Taper) uses a 60° thread angle and is common on American equipment. The two are not interchangeable — mismatching causes leaks and can damage fittings even if they appear to thread together. Q: How do I know which tap size to buy? Match the tap to the bolt thread you need — an M6 × 1.0 tap cuts the thread for an M6 coarse bolt. Always pair taps with the correct pilot drill from a tap drill chart. For blind holes, buy a taper, plug, and bottoming tap set. For through holes, a plug tap alone is usually sufficient for most trade applications. For machining, see our machining range stocked across Australia. Looking for long drill bits? Our long drill bits range covers the common sizes and brands. Prefer an interactive lookup? Use the AIMS Tap & Drill Selector tool to get the right tap and drill by thread type, size and material.
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AIMS Tap & Die Selection Guide: Hand, Spiral Point, Spiral Flute & Forming
A practical guide to selecting the right tap and die for the thread you're cutting. Covers hand taps (taper, plug, bottoming), spiral point taps for through holes, spiral flute taps for blind holes, thread forming taps for ductile material, machine nut taps, die nuts, button dies and die holders. Includes thread system selection (metric, BSP, BSPT, NPT, UNC, UNF, BSW, BSF), tap drill sizing, brand selection across Sutton Tools and Bordo, and AS/NZS/ISO standards.
Read moreAIMS Drill Bit Selection Guide: Choose by Material, Application & Cost
A practical guide to selecting the right drill bit for the workpiece you're cutting. Covers HSS, cobalt HSS, solid carbide, carbide-tipped, masonry, tile and glass drill bits, plus jobber, stub, step and SDS sub-types. Includes drill point geometry, coatings, brand selection across Sutton Tools, Bordo and P&N, and AS/NZS/ISO standards relevant to Australian industry.
Read moreBandsaw Blade Guide: TPI, Bi-Metal vs Carbide, Materials & Selection
A bandsaw is one of the most versatile cutting machines you can have in a workshop. The blade is what makes it work — and getting the blade selection right is the difference between a clean, fast, square cut and a smoking blade with stripped teeth twenty minutes after fitting. Bandsaws cut everything from solid round bar to structural sections, sheet metal, tube, plastic, hardwood, softwood, and on dedicated machines, meat. The same machine can run dramatically different blades depending on the job. That flexibility is the bandsaw's biggest strength — and also where most operators come unstuck. This guide covers what matters across the four big bandsaw applications: metal cutting (where most industrial bandsaws live), woodworking (carpentry workshops and joinery), portable bandsaws (Milwaukee M12/M18, DeWalt 20V, etc.), and meat processing (commercial butchering and food production). The focus is industrial — what tradespeople, fabricators, fitters and engineers actually need to know — with honest scope statements about which categories AIMS stocks and which we source on request. AIMS Industrial is an authorised Excision bandsaw blade distributor. Excision is Australian-owned, has been engineering precision cutting solutions for 30+ years, and their Bi-Alfa Cobalt M42 bi-metal range — along with Bi-Alfa Master Supreme for premium production, M51 cobalt-tungsten for exotic alloys, Bi-Alfa Cobalt Timber for woodworking, and TCT carbide-tipped blades for hardened materials — is the commercial centrepiece of this guide. The technical content applies regardless of brand; the product references are for buyers who want to know exactly what we stock and can source. Bandsaw Blade Selector — Match Blade to Material This guide is a working bandsaw blade selector. Use the scenarios below to find the right grade + TPI fast, then scroll for the full TPI rule, materials breakdown, and Excision range. How to use: 1. Match material + thickness 2. Read the recommended grade + TPI 3. Open the AIMS Excision range Sheet Metal & Thin Tube M42 18–24 TPI constant — fine tooth 18–24 TPI View → General Steel Workshop M42 6–10 TPI variable — workshop default 6–10 TPI View → Heavy Solid Bar / Billet M42 2–3 TPI variable — coarse pitch 2–3 TPI View → Stainless Steel (304/316) M51 cobalt 2/3 or 3/4 TPI — work-hardening M51 View → Hardened Steel / Inconel M51 cobalt or carbide-tipped Cobalt / Carbide View → Aluminium / Non-ferrous Skip-tooth, 4–6 TPI — chip clearance Skip View → Resawing Hardwood Skip or hook tooth 3–6 TPI Resaw View → Browse Excision XDP Coolants Bandsaw life extension Coolants View → Quick rule: keep 3–6 teeth in the workpiece. Thin material = fine TPI. Thick solid bar = coarse TPI. Bi-metal M42 is the workshop default for steel; cobalt M51 steps up for stainless and hardened steel; carbide-tipped for production cutting Inconel, Hastelloy, or high-alloy work. AIMS stocks the full Excision Bi-Alfa range — Australian-owned, 30+ years AU market presence. Need help? Call (02) 9773 0122. Jump to: TPI Rule Pitch Materials Tooth Set Cutting Metal Stainless Carbide Excision Range Brand Reality Related Selectors AIMS Top Picks — Pick the Right Excision Bandsaw Blade Excision is AIMS's bandsaw moat — 219 Bi-Alfa Cobalt M51/M42 blades + 39 XDP cutting fluids/coolants, all Australian-owned, 30+ years AU market presence. Recommendations below by material × thickness × dimension. Open the linked product for blade length/width/thickness selection. Call (02) 9773 0122. By Material — Match Grade to Workpiece Material Grade + TPI AIMS recommendation Why this one General mild steel (workshop default) M42 bi-metal Excision Bi-Alfa M42 Series M42 cobalt bi-metal — the AU workshop default. 4-5× life of carbon steel blade. Browse by size in the collection Heavy production (high MRR mild steel) M42 Original Profile Excision Bi-Alfa Original Profile M42 Original Profile geometry — Excision's heavy-stock production tooth pattern Stainless steel (304/316) M51 cobalt Excision Bi-Alfa Cobalt M51 Series M51 cobalt grade — step up from M42 for stainless. Resists work-hardening, 2-3× life on stainless Hardened steel / Inconel M51 or carbide-tipped Excision M51 Cobalt For >30 HRC, M51 is the floor. For Inconel + hardened tool steel, step up to carbide-tipped (call us) Aluminium / non-ferrous M42 with skip tooth Excision M42 Skip Tooth Skip tooth pattern — coarse pitch for chip clearance on aluminium and soft materials Resawing hardwood M42 with hook tooth Excision M42 Hook Tooth Hook tooth — for resawing thick hardwood. 3-6 TPI on the wood-cutting bandsaws By Bandsaw Machine Size (Length × Width) Common machine Blade size AIMS recommendation Why this one Bench bandsaw 250mm Ø 2080 × 20 × 0.9mm Excision M42 2080×20×0.9mm 8 TPI Common bench bandsaw size — 8 TPI for general workshop cutting Workshop bandsaw 350mm Ø 4450 × 34 × 1.1mm Excision M42 Original Profile 4450×34×1.1mm 3/4 TPI Mid-size workshop machine — 3/4 variable TPI for general fab work Production bandsaw 450-500mm Ø 4725 × 41 × 1.3mm Excision M51 Cobalt 4725×41×1.3mm 4/6 TPI M51 cobalt for production machine — heavier section for higher cutting pressure Heavy production 600mm+ 6600 × 54 × 1.6mm Excision M51 Cobalt 6600×54×1.6mm 2/3 TPI Large production bandsaw — 54mm width + 1.6mm thickness for heavy steel work Excision XDP Coolants & Cutting Fluids Application AIMS recommendation Why this one Workshop bandsaw coolant (semi-synthetic) Excision XDP2000 Semi-Synthetic Coolant 10L Ebox The Excision workshop bandsaw default — semi-synthetic 5-10% water mix. 10L Ebox for production use Cutting paste with applicator Excision XDP905 Cutting Paste Tube w/ Brush 200g Tube + brush format — for manual hacksaw + occasional bandsaw work without coolant system Plasma protector (downstream parts) Excision XDP4500 Plasma Protector 10L For plasma cutting line — protects against splatter contamination on downstream parts Buying tip from AIMS: Match BLADE SIZE to your machine first (length × width × thickness), then match GRADE to material (M42 default mild, M51 for stainless/tough), then TPI to section thickness (3-6 TPI for thick solid, 8-14 TPI for thin tube). Excision is Australian-owned and stocked across the AU industrial supply chain. AIMS holds the full Bi-Alfa range — call us with your machine make/model and we'll cross-reference to the right Excision blade. Coolant matters — bandsaw blade life DOUBLES with proper Excision XDP2000 coolant flow vs running dry.What is a bandsaw blade? A bandsaw blade is a continuous loop of toothed steel running on two or more wheels, with the cutting action coming from teeth on one edge that engage the workpiece as the loop moves past at high linear speed. Unlike a hacksaw (reciprocating, slow, manual) or a circular saw (rotating, high RPM, short engagement), the bandsaw maintains continuous tooth engagement with predictable chip clearance — which is why it's the standard cutting machine in metal workshops, joineries, and butcher shops worldwide. The blade itself is welded into a loop from coil stock. Commercial bandsaw blade manufacturers — Excision, Lenox, Starrett, Wikus, Bahco, M.K. Morse — supply blades either pre-welded to length, or as coil stock that workshops weld to size in-house using a blade welder. Excision blades for AIMS Industrial come pre-welded to the exact length you need for your machine. Three things define a bandsaw blade: geometry (width, thickness, length, TPI, tooth set, tooth shape), material (carbon steel, bi-metal M42, bi-metal M51, carbide tipped, or diamond), and welded length (specific to your machine). Get any one wrong and the blade won't cut properly — or won't cut at all. The two questions to ask before you buy Every other selection decision flows from these two: What's the diameter or wall thickness of what you're cutting? This drives TPI selection. Thin material needs more teeth in the cut (24 TPI for under 3mm); thick solid material needs fewer (3 TPI for 200mm solid steel). What's the welded length your machine needs? This is fixed by your machine — measure the old blade or check the machine plate. Excision's standard pre-welded lengths cover from 685mm (small benchtop verticals) through 13,000mm (large horizontals and production machines). Width and thickness are secondary — they're determined by your machine's blade guides, wheel diameter, and the cut radius (if you're contour cutting on a vertical saw). For straight cutting on horizontal saws, run the widest blade your machine accepts. Material grade (carbon steel vs M42 vs M51 vs carbide) is a productivity and cost decision — covered in the materials H2 below. TPI selection — the 3-to-6 teeth in workpiece rule This is the universal bandsaw blade selection law: you want between 3 and 6 teeth engaged with the workpiece at all times. Too few teeth (less than 3) and individual teeth take too big a bite, strip from the blade, or grab and snap. Too many teeth (more than 12) and the gullets between teeth clog with chips, heat builds up, and the blade burns out fast. For metal cutting on horizontal bandsaws, the practical range is 6–24 teeth in the cut depending on material thickness. For wood cutting on vertical bandsaws, the range is wider — 3–6 teeth is the working window because wood chips are larger and gullets need more clearance. The table below maps workpiece thickness to recommended TPI for metal cutting: Material thickness / diameter Recommended TPI Excision example Under 3mm (sheet metal, thin tube) 18–24 TPI constant M42 20×0.9×18 TPI 3–6mm wall (light tube, square section) 14 TPI constant M42 10×0.9×10/14 TPI variable 6–12mm (thicker tube, light solid) 10/14 TPI variable M42 10/14 TPI variable 12–25mm solid bar / 8mm wall tube 8/12 TPI variable M42 13×0.9×8/12 TPI variable 25–50mm solid bar / heavy section 5/7 or 6/10 TPI variable M42 27×0.9×5/7 TPI variable 50–100mm solid bar / structural section 4/6 TPI variable M42 27×0.9×4/6 TPI variable 100–200mm solid bar 3/4 TPI variable M42 34×1.1×3/4 TPI variable 200mm+ solid bar / heavy plate 1.5/2 or 2/3 TPI variable Specialist — contact us The single biggest mistake we see is operators running a 14 TPI blade because "it cuts smoother" — on 50mm solid bar, the gullets clog within minutes and the blade is junk. Coarse teeth on thick material isn't rough — it's correct. Constant pitch vs variable pitch A constant pitch blade has every tooth the same distance apart — 14 TPI means 14 teeth per inch, evenly spaced. A variable pitch blade has teeth spaced at varying distances along the length — designated as a range like 4/6, 8/12, or 10/14, where 4/6 means the pitch varies between 4 and 6 teeth per inch within the same blade. Variable pitch is the modern industrial default for two reasons. First, varying the tooth spacing breaks up the harmonic vibration that constant-pitch blades generate when teeth enter and exit the cut at the same frequency. This means less chatter, smoother cut, and longer blade life. Second, variable pitch widens the effective material thickness range of a single blade — a 4/6 TPI variable will cut both 75mm solid bar (where 6 TPI is right) and 50mm solid bar (where 4 TPI suits) without changing blades. The Excision Bi-Alfa Cobalt M42 range is built around variable pitch designations: 4/6, 5/7, 5/8, 6/10, 7/9, 8/12, 10/14, and 12/16. For general-purpose metal cutting on horizontal bandsaws, the most useful variables are 8/12 TPI for general work under 50mm and 4/6 TPI for 50mm and up. Constant pitch still has its place — 18 TPI and 24 TPI for thin sheet metal and tube where the cut is too short to benefit from variable spacing, and 3 TPI for heavy solid where there's no harmonic problem to solve. Blade materials decoded — carbon, M42, M51, carbide, diamond Bandsaw blade material is the productivity decision. Cheap carbon steel blades work fine for occasional cutting; bi-metal M42 outlasts them 5–10× on production work; M51 lasts longer again on exotic alloys; carbide tipped is the only realistic option for hardened steel and extreme materials. Diamond blades are a specialist application for hard non-metallics. Material Tooth structure Best for Cost vs M42 Hardened carbon steel One-piece hardened carbon spring steel Light/occasional cutting, soft non-ferrous, wood 0.2–0.3× Bi-metal M2 HSS tooth tip electron-beam welded to spring steel back Light steel, aluminium, brass — entry bi-metal 0.7–0.8× Bi-metal M42 M42 HSS (8% cobalt) tip welded to spring steel back The workshop standard — mild steel, alloy, stainless, structural 1.0× (baseline) Bi-metal M51 M51 HSS (10% cobalt + 10% tungsten) tip on spring steel back Stainless 316/duplex, Inconel, titanium, tool steel — exotic alloys 1.5–2.0× Carbide tipped (TCT) Brazed tungsten carbide teeth on alloy steel back Hardened steel (Rc >45), case-hardened bar, abrasive material 3.0–5.0× Diamond / CBN Diamond grit or CBN bonded to steel band Hard non-metallics (graphite, ceramics, glass), composites 4.0–8.0× The workshop default is bi-metal M42. An M42 blade will outlast a hardened carbon blade by 5–10× on the same material, which more than pays for the 3–4× price premium. Carbon-steel-only is a false economy on anything but occasional cutting — you'll change blades constantly and the chipped teeth will leave a rough cut and accelerate machine wear. M42 vs M51 is a more nuanced decision. M42's 8% cobalt content gives heat resistance to about 500°C at the tooth tip. M51 (10% cobalt + 10% tungsten) extends that to about 600°C and adds significant wear resistance against abrasive alloying elements. The practical M42-to-M51 step-up is justified when you're cutting Inconel, titanium, duplex stainless, or hardened tool steels in production volume — the blade lasts 50–100% longer and finishes the cut cooler. For mild steel, standard 304/316 stainless, and structural sections, M42 is the right answer. The Excision range covers all five tiers: Bi-Alfa Cobalt M42 as the volume range, Bi-Alfa Master Supreme as the premium production tier, M51 cobalt-tungsten for exotic alloys, and TCT carbide-tipped blades for hardened materials (sourced from Excision's TCT range — contact us for specification). Tooth set patterns — raker, alternate, wavy Tooth set is the lateral bending of teeth to create a kerf wider than the blade body, preventing the blade from binding in the cut. Three patterns dominate: Set pattern Tooth sequence Best for Raker set Right / left / straight (raker) — repeating 3-tooth cycle General-purpose default — most metal cutting, contour cutting Alternate set Right / left alternating, no raker Fast material removal where surface finish doesn't matter Wavy set Groups of teeth set right, then groups set left — wave pattern Thin sheet, tube, variable thickness without changing blades For 90% of metal cutting applications, raker set is the right answer — it's the default on Excision Bi-Alfa M42 and M51 blades. Wavy set appears on the higher-TPI constant pitch blades (18 TPI and 24 TPI) used for thin material, because the wave pattern handles variable section thicknesses without changing blades. Alternate set is reserved for production roughing where the cut surface gets machined or ground afterwards. Tooth geometry — regular, hook, skip Tooth geometry is the shape of the tooth face, which determines how aggressively the tooth bites into the material and how chips evacuate. Geometry Rake angle Gullet Best for Regular (standard) 0° rake Standard depth Ferrous metals, general workshop — the default Hook 10° positive rake Large, rounded Aggressive cutting, wood, plastic, non-ferrous — fast feed Skip 0° rake, every other tooth removed Very large Soft non-ferrous, wood (especially resin-loaded), gummy materials Regular tooth is the standard on the Excision Bi-Alfa Cobalt M42 metal-cutting range — it cuts ferrous metals predictably with minimum chatter and good surface finish. Hook tooth shows up on wood-specific blades and aluminium-cutting blades where the more aggressive engagement and larger gullets keep up with bigger chips. Skip tooth is a wood and soft-material specialty — you'll see it on resaw blades for thick boards where chip clearance is critical. Cutting metal — bi-metal M42 as the workshop default The Excision Bi-Alfa Cobalt M42 range covers virtually every metal cutting application a workshop encounters. Width options from 6mm (small benchtop verticals) through 80mm (production horizontals), thickness 0.5–1.6mm depending on width, TPI from 1.25 to 25, and welded lengths from 685mm to 13,000mm. For metal cutting on a horizontal bandsaw, three things drive cut quality: correct TPI, correct speed (SFM) for the material, and adequate coolant. The TPI selection table earlier in this guide covers point one. The cutting speed table below covers point two for the common materials: Material Bandsaw cutting speed (SFM) Bandsaw cutting speed (m/min) Coolant Mild steel (1018, 1020) 200–300 SFM 60–90 m/min Water-soluble emulsion Medium carbon (4140, 4340) 150–200 SFM 45–60 m/min Water-soluble emulsion Tool steel annealed (O1, A2) 80–120 SFM 25–35 m/min Water-soluble + EP additive Stainless 304/316 90–140 SFM 27–42 m/min Water-soluble + sulphur EP additive Stainless duplex / 17-4PH 60–90 SFM 18–27 m/min Heavy EP soluble, M51 blade preferred Inconel / Hastelloy / Ti 40–80 SFM 12–25 m/min Heavy EP, M51 mandatory, slow + heavy feed Aluminium 1000–3000 SFM 300–900 m/min Mist or kerosene, never dry Brass / bronze 200–500 SFM 60–150 m/min Dry or light mist Cast iron 200–250 SFM 60–75 m/min Dry — never with coolant The cutting speeds and feeds chart covers the broader workshop cutting speed reference. For coolant selection, see the cutting fluids guide — water-soluble emulsion at 5–10% mix is the bandsaw default for ferrous metal cutting; Excision's XDP-series soluble oils are formulated for this application. Cutting stainless — the work-hardening trap The single biggest mistake on stainless steel: stopping the feed mid-cut. If the blade is rubbing without cutting — even for a few seconds — the surface work-hardens instantly. The next pass of teeth hits hardened material and chips. Within seconds the blade is destroyed. Austenitic stainless steel (304, 316) work-hardens when deformed without being cut. The instant you reduce feed pressure below the threshold needed to keep teeth biting through the surface, the teeth start sliding instead of cutting. The friction work-hardens the surface to Rockwell C 50+. The next teeth in the cut now hit that hardened layer and chip immediately. Once teeth chip, the rest of the blade follows in seconds. Three rules for stainless on a bandsaw: Drop the TPI — coarser teeth take a bigger bite per tooth, so the force per tooth is higher and they push through the surface instead of skating on it. A 6/10 TPI variable on 25mm stainless beats a 10/14 TPI variable on the same job. Never stop the feed mid-cut — if you have to stop the saw, retract the blade out of the cut first. Then stop. Don't leave teeth in contact with stationary stainless. Coolant is non-negotiable — heavy water-soluble emulsion with sulphur-based EP additive. Dry-cutting stainless on a bandsaw is a guaranteed blade-killer. For duplex stainless (2205, 2507), 17-4PH precipitation hardened, or 316L in production volumes, step up from Excision M42 to Excision M51 cobalt-tungsten. The extra heat resistance and wear resistance is the difference between consistent production and frequent blade changes. Cutting wood on a bandsaw — the AU hardwood reality Wood bandsaw blades face a different challenge to metal blades. Wood produces large chips that need large gullets. The cutting forces are lower per tooth, but the chip volume per tooth is much higher. This is why dedicated wood bandsaw blades use hook tooth geometry, skip tooth patterns, and lower TPI — typically 3 TPI to 14 TPI depending on what you're cutting. Australian hardwoods are the international outlier in bandsaw cutting. Janka hardness ratings tell the story: jarrah comes in at 8.5 kN, ironbark at 14.2 kN, spotted gum at 11.0 kN. Compare to the international softwood baseline (pine at 1.5 kN, Douglas fir at 2.4 kN) and you can see why imported standard wood bandsaw blades — designed primarily for North American and European softwoods — dull fast on AU hardwoods. The Excision Bi-Alfa Cobalt Timber range is the bi-metal answer for hardwood. M42 cobalt tooth tips on a flexible carbon-steel back — the same construction philosophy as the M42 metal-cutting range, but with hook tooth geometry, larger gullets, and TPI selections optimised for wood. The result is a wood bandsaw blade that holds its edge through AU hardwoods where standard carbon-steel imported blades dull within hours. For resawing (cutting boards along their length to make thinner boards), the workshop default on 14"–18" bandsaws is a 1/2" (12.7mm) blade at 3 TPI hook tooth. For general bench work and scrolling on the same machine, 3/8" (9.5mm) at 4 TPI skip tooth is the most-versatile blade. Resin-loaded woods (Sydney blue gum, cypress) benefit from skip tooth more than hook tooth — the bigger gullets shed sticky chip pack faster. A practical note from AU joiners on woodworkforums.com.au: a bandsaw spec'd for a 19mm (3/4") blade can usually only tension a 16mm (5/8") blade properly — manufacturer width claims are optimistic. If you're not getting clean cuts on a wide blade, drop a size before assuming the blade is faulty. Resawing thick boards — width, TPI, technique Resawing is the highest-demand wood bandsaw operation — cutting boards along their length, often through 100mm+ of hardwood. Three things matter: blade width (for beam strength and straight cuts), TPI (for chip clearance), and machine tension (for accurate tracking). Resaw depth Blade width TPI Tooth geometry Up to 75mm (3") 1/4" (6mm) to 3/8" (9.5mm) 6 TPI Skip or hook 75–150mm (3–6") 1/2" (12.7mm) 3 TPI Hook 150–250mm (6–10") 5/8" (16mm) to 3/4" (19mm) 2–3 TPI Hook 250mm+ (10"+) 3/4" (19mm) to 1" (25mm) 1.3–2 TPI Hook, sometimes carbide tipped Beam strength matters more than tooth aggression on tall resaws. A 1/2" blade has roughly 4× the beam strength of a 1/4" blade — it tracks straighter and resists deflection from grain irregularities. The trade-off is wheel diameter: narrower blades flex around smaller wheels without metal fatigue, wider blades need larger wheel diameters. Drift adjustment — the tendency of a blade to wander left or right of the cut line — is the resawing skill that takes practice. Each blade has a "natural drift angle" determined by tooth set asymmetry and blade tension. Adjust your fence parallel to the drift angle, not parallel to the blade body. Skipping this step is why straight resaws look bowed. Cutting meat — honest scope Meat bandsaw blades are a different product class to industrial metal-cutting bandsaw blades. Commercial butcher bandsaws (Hobart, Biro, Butcher Boy, Hollymatic, Torrey) use stainless steel blades, typically 3 TPI raker tooth, around 5/8" (16mm) wide, .022" thick, with rounded tooth profiles designed to cut bone and meat without splintering bone or leaving sharp burrs. Meat bandsaw blades face four requirements that don't apply to industrial metal blades: Hygiene and food safety — stainless steel construction, smooth non-porous surfaces, designed for cleanability per Australian Standard AS 4696:2023 (Hygienic Production and Transportation of Meat and Meat Products for Human Consumption — current standard, replaced AS 4696:2007 from 01/07/23 in export-registered meat establishments). Corrosion resistance — meat acids and salt brines corrode standard carbon-steel and bi-metal blades within days. Stainless construction is non-negotiable for food contact. NSF/ANSI/3-A certification — the international hygiene standard for food-cutting equipment design. Recognised by AU Food Standards. Tooth profile for bone — meat blades use rounded raker teeth to cut bone cleanly without producing sharp bone splinters that contaminate the meat. AIMS Industrial does not stock dedicated meat bandsaw blades — the food-grade equipment supply chain is separate from industrial metal cutting, and the technical requirements (food-safe materials, cleanability certification, butcher-machine compatibility) are best served by specialist food-processing equipment distributors. If you're in commercial meat processing and looking for replacement blades for your Hobart, Biro, or Butcher Boy bandsaw, contact us and we'll point you to the right Australian specialist. A hunter or small-scale butcher with a wood bandsaw asking "can I use my wood bandsaw to cut venison or beef quarters at home?" — yes, with caveats. Fit a coarse 4 TPI blade, clean the machine thoroughly after every use (meat acids and fat corrode wood-bandsaw mechanical components fast if left), and don't use the same blade for wood afterwards. For domestic and hunting use this works fine; for commercial food production, use proper food-grade equipment. Portable bandsaw blades (Milwaukee, DeWalt, M12/M18) Portable bandsaws — Milwaukee M12 Sub-Compact, Milwaukee M18 Deep Cut, DeWalt 20V MAX, Makita XBP02 — use shorter blades (typically 600–900mm welded length) at higher TPI than horizontal bandsaws. The Lenox Diemaster 2 (M42 bi-metal, 14 TPI or 10/14 variable) is the workshop consensus replacement for OEM blades across all the major brand portables. Why portable bandsaws need different blades: the wheel diameter is smaller (typically 38–50mm vs 250mm+ on horizontal saws), so blade flex around the wheels is much higher. This means thinner blade backs (typically 0.6mm vs 0.9–1.3mm), higher TPI to keep cut forces low, and bi-metal M42 as the practical material standard. AIMS does not stock portable bandsaw blades. Excision's range is focused on industrial horizontal and vertical bandsaw machines, not battery-platform portables. For Milwaukee M12 or M18 replacement blades, M.K. Morse 811 series (about 2× faster than OEM Milwaukee blades per WeldingWeb consensus) and Lenox Diemaster 2 are the gold-standard options — both available through dedicated portable-tool retailers in Australia. Carbide tipped bandsaw blades — when you need them Carbide-tipped (TCT) bandsaw blades use tungsten carbide teeth brazed to an alloy steel back. They're the only realistic blade for cutting: Hardened steel above Rockwell C 45 (tool steel after heat treatment, case-hardened pins, hardfaced components) Abrasive materials (high-silicon aluminium castings, glass-filled composites, fibreglass) Production cutting of standard alloys at maximum throughput Specialty applications (structural sections, very thick solid bar) The catch: TCT bandsaw blades require a rigid machine. Carbide is brittle. If your machine flexes — worn guide bearings, undertensioned blade, vibration from worn drive components — carbide teeth chip off. Once a TCT blade loses one or two teeth, the remaining teeth take heavier loads and chip in cascade. As one Hobby-Machinist contributor put it bluntly: "you must stop before shucking off more." TCT blades typically use 20° negative tooth rake — different from the positive or zero rake on bi-metal blades — for tooth strength. This means the blade pushes against the cut rather than pulling teeth into it, which is what brittle carbide needs to survive the impact-load of entering and exiting the cut. Excision's TCT bandsaw blade range covers the carbide tier. AIMS can source any Excision TCT specification — including specialty applications like hardened tool steel cutting, high-strength alloy structural sections, and abrasive composite cutting. Contact us with your machine details, material, and cut volume for a TCT specification. Blade break-in procedure — the most-skipped fundamental What break-in does: New bi-metal teeth have microscopically sharp edges from the grinding and tempering process. Running a new blade at full feed for the first cuts chips these edges immediately — the blade loses its theoretical edge life from day one. Properly broken-in teeth have smoothly-rounded edges that cut for the blade's full design life. Break-in protocol — the universal standard across every bandsaw blade manufacturer (Excision, Lenox, Starrett, Wikus all publish similar): Cutting speed: normal SFM for the material (per the table earlier in this guide). Speed isn't the variable being controlled during break-in. Feed pressure: reduce to half of normal for easier materials (mild steel, aluminium, brass) or to one-third of normal for harder materials (stainless, alloy steel, tool steel). Duration: first 50–150 square inches of cut, or roughly the first 10 minutes of continuous cutting. For a 50mm bar, that's 8–15 cuts depending on diameter. Ramp up gradually: after the break-in cuts, ramp feed back to normal over the next 5–10 cuts. Don't jump straight back to maximum feed. Why skipping break-in costs you blade life: under microscope, a broken-in tooth has a smooth, rounded edge profile that distributes cutting load across a small contact area. An unbroken-in tooth has the original sharp edge — which is mechanically weaker than the broken-in profile and chips off in tiny fragments during the first heavy cuts. Once chipped, the tooth can't recover. The blade is permanently down on theoretical life from day one. For workshops cutting mixed materials, run break-in on the easiest material in your queue (mild steel works well). The broken-in blade is then ready for whatever comes next — including the harder materials that you would have damaged the blade on if cut first. Common bandsaw blade failure modes Bandsaw blades don't just dull — they fail in specific, identifiable ways. Recognising the failure mode tells you what went wrong and what to fix. Failure mode What it looks like Cause + fix Tooth strip Multiple adjacent teeth ripped off cleanly TPI too coarse for material — fewer than 3 teeth in workpiece. Drop to finer TPI. Weld snap Blade breaks at the welded join Cheap blade, defective weld, or excessive twist around small wheels. Buy quality, check tracking. Wheel-fatigue snap Blade snaps mid-band, teeth still sharp Metal fatigue from twist+bend cycles around wheels. Normal end-of-life — blade has run its design hours. Work-hardening tooth chip Tooth edges chipped after stainless cut Feed stopped mid-cut on austenitic stainless. Never stop in the cut; retract first. Gullet overload Heat blueing, burnt finish, glazed teeth TPI too fine for material — more than 12 teeth in workpiece. Step up to coarser TPI. Blade walk / wandering cut Cut is not square, drifts off line Worn guides, low tension, asymmetric tooth wear from cutting harder material on one side. Vibration chatter Wavy cut surface, audible chatter during cut Constant pitch resonating with cutting frequency. Switch to variable pitch. Premature dulling Blade slow within first hour of use Skipped break-in, wrong material grade (carbon on stainless), or wrong coolant. A bandsaw blade that has cut its design life will typically show even tooth wear across the full length, gradual loss of cutting speed, and eventually rounded tooth tips visible under magnification. This is normal end-of-life. Catastrophic failure (snapping, tooth strip, weld snap) within the first few hours of running is always traceable to one of the causes above — diagnose the cause before fitting the replacement blade or you'll destroy that one the same way. DIY blade welding from coil stock Production workshops that go through dozens of bandsaw blades per year sometimes weld their own from coil stock. Coil stock is sold in 30m or 50m rolls — significantly cheaper per metre than pre-welded blades. The breakeven calculation: how many blades per year times the price-per-metre saving versus the cost of a blade welder ($800–$3,000 for a manual resistance butt welder, $5,000+ for production-tier). The proper method is resistance butt welding — the blade ends are clamped in jaws, current passes through the join, the join heats to forging temperature, and pressure forges the joint. Vertical contour bandsaws (DoAll, Marvel) have built-in resistance welders. Standalone bench welders work the same way. DIY methods for occasional one-off blade welds (without a dedicated bandsaw welder): Silver soldering with a 1/2" lap joint and alignment fixture — cost-effective for thin blades (0.6mm), reliable if surface prep is correct. TIG welding with thin stainless filler rod — works well on thicker blades (0.9–1.3mm), requires steady hand and clean alignment. MIG welding on low settings — documented in machinist forums but harder to get right on thin material; not the recommended method. The non-negotiable prep step for any welding method: remove the bluing and oxide from both blade ends with abrasive paper or a wire wheel. Welding through oxide gives a weld that snaps on startup. Clean, bright metal at the join is the difference between a blade that runs and a blade that breaks. The Excision Bi-Alfa range — what AIMS stocks and sources Excision's Bi-Alfa range is built around the philosophy that Australian workshops deserve precision cutting solutions made for Australian conditions — and backed by local technical support. AIMS Industrial stocks 220+ Excision bandsaw blade SKUs in the dedicated Band Saw Blades collection, with coverage across: Bi-Alfa Cobalt M42 — the workshop standard bi-metal range. Widths 6mm through 67mm, thicknesses 0.5–1.6mm, TPI from 3 to 25 (constant and variable), welded lengths 685–13,000mm. This covers virtually every horizontal and vertical bandsaw application across mild steel, alloy steel, stainless 304/316, and structural sections. The 27×0.9×4/6 TPI variable and 27×0.9×5/7 TPI variable are the most-ordered sizes for general workshop bandsaws. Bi-Alfa Master Supreme — Excision's premium production tier. Heavier construction, larger welded lengths (5,200–13,000mm), designed for high-volume production cutting where blade life and consistency justify the price step. Sizes 34mm × 1.1mm × 3/4 TPI (3810–5200mm) through 67mm × 1.6mm × 1.5/2 TPI (7320–10110mm) in stock. Bi-Alfa M42 Profile WS — welded specialty profile range for cutting hardened materials and difficult sections. 67×1.6×3/4 TPI Profile WS is the most-spec'd size for structural section cutting. Bi-Alfa Cobalt M51 — for exotic alloys (Inconel, titanium, duplex stainless, hardened tool steel). 10% cobalt + 10% tungsten gives extended heat resistance and wear resistance vs M42. Available in 27mm × 0.9mm × 3/4 TPI and larger sizes including 4725mm × 41mm × 1.3mm × 4/6 TPI for production cutting. Bi-Alfa Cobalt Timber — Excision's bi-metal range for woodworking. The bi-metal construction gives extended life on Australian hardwoods (jarrah, ironbark, spotted gum, blackbutt) where standard carbon-steel imported wood blades dull within hours. Two stocked SKUs in the main collection. TCT carbide-tipped — the carbide tier for hardened steel (Rc 45+), abrasive composites, and production cutting of standard alloys at maximum throughput. AIMS sources from Excision's TCT bandsaw blade range — contact us with machine, material, and cut volume for specification. For sizes or specifications outside what's in the live collection, AIMS can source any product from the Excision range — including custom welded lengths, specialty profile sections, and Cermet-tipped specialty blades. Excision manufactures in 30m and 50m coil stock and welds to specification, with 95% fill rate on standard items. Brand reality — Excision vs Lenox vs Starrett vs Wikus The international bandsaw blade market has consolidated significantly in the last decade, and brand reputation has shifted with it. The honest reality from machinist forums: Brand Origin Reputation (forum-validated) Excision Australian-owned, manufacturing partnerships in Italy + AU custom welding 30+ years AU market presence, local technical support, full range coverage from workshop M42 through Master Supreme production tier and TCT carbide. The AIMS commercial recommendation. Lenox US — acquired by Stanley/Irwin Historical gold standard, but quality has slipped since acquisition per Practical Machinist + Garage Journal 2023+ threads. Diemaster 2 portable range still consensus-best for portables. Starrett US Mixed reputation — Practical Machinist production threads cite weld-snap failures more frequently than Lenox or Excision. Workshop-tier blades acceptable; production-tier mixed. Wikus German Premium European tier, excellent quality, but limited AU distribution — typically requires direct-from-importer specification and lead time. The benchmark for what production-tier should be. M.K. Morse US Mid-tier general-purpose, strong on portables (M.K. Morse 811 portable cuts roughly 2× faster than OEM Milwaukee per WeldingWeb consensus). Entry tier on horizontal saws. Bahco Swedish + UK + variable origin Mid-tier general-purpose, good value, but inconsistent batch quality depending on country of manufacture. UK-made stock generally better than European budget stock. Amada Japanese Premium production tier, excellent on Japanese OEM machines, limited AU distribution outside Amada-specific dealer channels. For Australian workshops, the Excision Bi-Alfa range covers the full spectrum without the lead time, distribution complexity, or quality-variance issues of the international alternatives. For premium European tier, Wikus is the international benchmark. For portables, Lenox Diemaster 2 remains the consensus answer. 8 common bandsaw blade mistakes Mistake What happens The fix Wrong TPI for material thickness Tooth strip (too coarse) or gullet overload (too fine) Use the 3-to-6 teeth in workpiece rule — see TPI table Skipping break-in on a new blade Permanent loss of blade life from day one 50–150 sq inches at half feed before ramping to normal Running stainless with too-fine teeth Work-hardening tooth chip within minutes Drop TPI — coarser teeth bite through the surface Stopping feed mid-cut on stainless Surface work-hardens, next pass kills teeth Retract blade before stopping, never leave teeth stationary in stainless Wrong coolant or no coolant on steel Heat blueing, accelerated tooth wear Water-soluble emulsion 5–10% for ferrous; cast iron dry only Tensioning by feel without gauge Wandering cuts, blade walk, premature weld failure Bandsaw blade tension meter — typically 200–300 N/mm² for bi-metal Using a wood-cutting machine for occasional metal work Wheel diameter and SFM mismatch — blade fails fast Use the right machine for the material; dedicated metal-cutting bandsaws have low SFM range Buying cheap import blades for production work Weld snap within 50 hours, inconsistent cut quality Specify quality blades from an authorised distributor — the price difference pays back in blade life Bandsaw blade safety also matters: always wear safety glasses at minimum (impact-rated for metal cutting), hearing protection for prolonged horizontal saw operation, and a P2 respirator for hardwood cutting (Australian Cancer Council classifies hardwood dust as a Group 1 carcinogen). The bandsaw guards (per AS/NZS 4024 series) must be in place and functional — the running blade is the highest-energy moving part in most workshops. Related AIMS Selectors This selector pairs with AIMS's other cutting-tool guides: Hacksaw Blade Guide — manual cutting counterpart: TPI, bi-metal vs HSS, blade size selection. Carbide vs HSS End Mill — same material trade-off in milling. Cutting Tool Materials Guide — HSS, M42, M51, cobalt, carbide compared. Cutting Speeds & Feeds Reference — SFM × material × tooth material. Cutting Tool Troubleshooting — tooth strip, blade breakage, chatter diagnosis. Material Cross-Reference Chart — workpiece identification + ISO grouping. End Mill Guide — when milling beats sawing. Cobalt Drill Bit Guide — cobalt material principle applied to drilling. Or browse the full Excision range — bandsaw blades (Bi-Alfa Cobalt M51 and M42 in stock for every common bandsaw size), Excision XDP coolants & cutting fluids, magnetic drills, GripLox pliers and earth clamps. Next-day Australia-wide dispatch from our Milperra warehouse.Frequently Asked Questions What TPI do I need for cutting steel on a bandsaw? For metal cutting on a horizontal bandsaw, target 6–24 teeth engaged with the workpiece at all times. Practical guide: 10/14 TPI for 6–12mm material, 8/12 TPI for 12–25mm solid bar, 5/7 or 6/10 TPI for 25–50mm solid, 4/6 TPI for 50–100mm solid, and 3/4 TPI for over 100mm. Thin sheet under 3mm uses 18–24 TPI constant pitch. The single biggest mistake is running fine teeth on thick material — gullets clog within minutes. What's the 3-to-6 teeth rule and why does it matter? The 3-to-6 teeth in workpiece rule is the universal bandsaw blade selection law: you want between 3 and 6 teeth engaged with the material at all times during the cut. Fewer than 3 teeth means each tooth takes too big a bite and they strip from the blade. More than 6 teeth (and especially more than 12) means the gullets between teeth clog with chips, heat builds up, and the blade burns out fast. For wood, the working range is 3–6 teeth. For metal, it widens to 6–24 teeth because metal chips are smaller per cubic millimetre cut. Bi-metal M42 vs carbon steel — which should I buy? Bi-metal M42 is the workshop standard. It outlasts a hardened carbon steel blade by 5–10× on the same material, which pays back the 3–4× price premium in blade life and consistency. Carbon-steel-only is acceptable for occasional cutting of soft materials (aluminium, brass, mild steel under 25mm) but a false economy for anything else. Run M42 as your default unless you're cutting hardwood, plastic, or aluminium where the cutting forces are low. What's the difference between M42 and M51 bi-metal? M42 has 8% cobalt in the HSS tooth tip and is the workshop standard for general metal cutting. M51 has 10% cobalt plus 10% tungsten, which extends heat resistance from about 500°C (M42) to about 600°C and adds significant wear resistance against abrasive alloying elements. The M42-to-M51 step-up is justified for production cutting of Inconel, titanium, duplex stainless, or hardened tool steels — blade life improves 50–100%. For mild steel and standard 304/316 stainless, M42 is the right answer. What is variable pitch and is it worth the extra cost? Variable pitch blades have teeth spaced at varying distances (designated as ranges like 4/6, 8/12, or 10/14) rather than all evenly spaced. The varying spacing breaks up the harmonic vibration that constant-pitch blades generate, reducing chatter and extending blade life by 20–40% on most applications. It also widens the effective material thickness range of a single blade. Yes — variable pitch is worth the marginal cost premium on virtually every metal cutting application above 6mm thickness. How do I break in a new bandsaw blade? Run the new blade at normal cutting speed (SFM) for the material, but reduce feed pressure to half normal (for mild steel, aluminium, brass) or one-third normal (for stainless, alloy steel, tool steel). Continue at reduced feed for the first 50–150 square inches of cut, or roughly 10 minutes of continuous cutting. Then ramp feed back to normal gradually over the next 5–10 cuts. Skipping break-in chips the microscopic tooth edges immediately and permanently reduces blade life from day one. Why do my bandsaw blades keep breaking? Three most-common causes: (1) weld snap from a defective blade weld or cheap import quality — buy quality blades from an authorised distributor; (2) wheel-fatigue snap from blades being twisted around wheels smaller than they're designed for, or from running blades past their design life; (3) work-hardening damage from stopping feed mid-cut on stainless steel, which work-hardens the surface and destroys teeth in seconds. Diagnose the failure mode before fitting the next blade — fitting a new blade without fixing the cause kills it the same way. Can I cut stainless steel on my bandsaw? Yes, with three rules: (1) drop the TPI compared to mild steel of the same thickness — coarser teeth bite through the work-hardened surface instead of skating on it; (2) never stop the feed mid-cut — if you have to stop, retract the blade out of the cut first; (3) use heavy water-soluble coolant with sulphur EP additive — dry-cutting stainless on a bandsaw is a guaranteed blade-killer. For duplex stainless or 316L in production volume, step up to M51 cobalt-tungsten blades. Can I use a wood bandsaw for cutting meat? For occasional domestic use (cutting up a venison carcass, breaking down beef quarters at home), yes — fit a coarse 4 TPI blade, clean the machine thoroughly after every use (meat acids and fat corrode mechanical components fast if left), and don't use the same blade for wood afterwards. For commercial meat processing, no — Australian Standard AS 4696:2023 requires hygienic food-grade equipment, stainless construction throughout, and cleanability certification. Use proper food-grade meat bandsaws (Hobart, Biro, Butcher Boy) for commercial production. What's the difference between regular, hook, and skip tooth? Regular tooth has 0° rake and standard gullet depth — the default for ferrous metal cutting, predictable and smooth. Hook tooth has 10° positive rake and larger gullets — aggressive cutting for wood, plastic, and non-ferrous metals where chip volume is high. Skip tooth has 0° rake but every other tooth removed, creating very large gullets — for soft non-ferrous and especially resin-loaded wood where sticky chips need to clear. For metal cutting on a standard bandsaw, regular tooth is what you want. Can you sharpen a bandsaw blade? Realistically, no — the cost of professionally sharpening a bandsaw blade exceeds the cost of replacement for almost all blade sizes. Specialty resharpening services exist for very large production-tier blades (typically over 27mm wide, M51 or carbide tipped, where the original blade cost was $300+), but for workshop-standard M42 blades under 27mm wide, replacement is more economical. Carbide-tipped TCT blades are sometimes worth resharpening — costs and economics depend on the carbide grade and tooth count. How do I measure a bandsaw blade for replacement? The critical dimension is welded length — measure the existing blade laid flat in a complete loop, or follow the machine plate / manufacturer specification. Width (typically 13mm, 20mm, 27mm, 34mm, 41mm, 67mm depending on machine class) is determined by your blade guides and wheel diameter — match the existing blade. Thickness is determined by the width (Excision uses 0.5mm at 6–13mm width, 0.9mm at 20–27mm width, 1.1mm at 34mm, 1.3mm at 41mm, 1.6mm at 54–80mm). TPI is the application decision — pick per the material thickness table in this guide. What blade do I need for resawing on a 14" bandsaw? The workshop default on 14"–18" wood bandsaws is a 1/2" (12.7mm) blade at 3 TPI hook tooth for resawing boards up to about 150mm tall. For taller resaws (150–250mm), step up to 5/8" (16mm) at 2–3 TPI hook tooth. For Australian hardwoods (jarrah, ironbark, spotted gum), bi-metal construction (Excision Bi-Alfa Cobalt Timber range) significantly outlasts standard carbon-steel imported wood blades. A practical note: a 14" bandsaw spec'd for 19mm blades can typically only tension a 16mm blade properly — drop a size if your blade isn't tracking straight. What blade for a portable bandsaw (Milwaukee M12/M18 or DeWalt)? Portable bandsaws use shorter blades (typically 600–900mm welded length) at higher TPI than horizontal saws — 10/14 TPI variable or 14 TPI constant for general work. The Lenox Diemaster 2 (M42 bi-metal) is the workshop consensus replacement for OEM blades across Milwaukee M12 Sub-Compact, M18 Deep Cut, DeWalt 20V MAX, and Makita XBP02. M.K. Morse 811 series is the second consensus option — cuts roughly 2× faster than OEM Milwaukee blades per WeldingWeb. AIMS does not stock portable bandsaw blades — Excision's range focuses on industrial machines. Lenox vs Starrett vs Excision — which brand? For Australian workshops in 2026, Excision is the AIMS recommendation — Australian-owned, 30+ years AU market presence, local technical support, and full range coverage from workshop M42 through Master Supreme production tier, M51 exotic alloy, and TCT carbide. Lenox historical reputation was the gold standard, but quality has slipped since the Stanley/Irwin acquisition per Practical Machinist and Garage Journal forum consensus. Starrett has mixed reputation — workshop-tier acceptable, production-tier reported with weld-snap failures more frequently than Excision or Lenox. For premium European tier, Wikus (German) is the benchmark but has limited AU distribution. What's the difference between raker, alternate and wavy tooth set? Raker set is right/left/straight repeating in a 3-tooth cycle — the general-purpose default used on most Excision Bi-Alfa M42 and M51 blades, right for around 90% of metal cutting. Alternate set is right/left alternating with no raker tooth, used for fast material removal where the cut surface doesn't matter because it gets machined or ground afterwards. Wavy set groups teeth right then left in a wave pattern and appears on higher-TPI constant pitch blades (18 TPI, 24 TPI) for thin material, handling variable section thickness without a blade change. What does a variable pitch designation like 4/6 or 8/12 mean? A variable pitch blade has teeth spaced at varying distances along its length rather than one constant spacing. A 4/6 designation means the tooth pitch varies between 4 and 6 teeth per inch within the same blade. This breaks up the harmonic vibration that constant-pitch blades generate when every tooth enters and exits the cut at the same frequency, giving a smoother cut and longer blade life, and it widens the effective material thickness range a single blade can handle — a 4/6 TPI blade cuts both 75mm solid bar (where 6 TPI suits) and 50mm solid bar (where 4 TPI suits) without changing blades. What's the correct bandsaw cutting speed for mild steel? Mild steel (1018, 1020) cuts at 200-300 SFM (60-90 m/min) on a horizontal bandsaw, with a water-soluble emulsion coolant. Cut quality on metal comes down to three things: correct TPI for the material thickness, correct cutting speed for the material, and adequate coolant — get any one of those wrong and blade life and cut finish both suffer. How much longer does a bi-metal M42 blade last than a carbon steel blade? Bi-metal M42 typically outlasts hardened carbon steel blades by 5-10x on production work. Carbon steel blades are fine for light or occasional cutting of soft non-ferrous metals or wood, but M42 — an HSS tooth tip with 8% cobalt, electron-beam welded to a spring steel back — is the workshop standard for mild steel, alloy, stainless and structural work where blade life matters. Need to size a metric bolt? Our Metric Bolt Size Guide covers M3 through M24 with coarse and fine threads.
Read moreSanding Disc & Abrasive Disc Guide: Grain, Backing, Hook-and-Loop & Tool Compatibility
Sanding discs decoded: aluminium oxide vs zirconia vs ceramic abrasive grain, hook-and-loop vs PSA backing, dust extraction holes, fibre disc setup and AU brand selection.
Read moreCobalt Drill Bit Guide: HSS-Co Grades, M35, M42 & When to Upgrade
The single most-asked question in any Australian metal-working workshop: "What drill bit do I use for stainless steel?" The answer, ninety percent of the time, is a cobalt drill bit. Understanding why takes a few minutes — and getting the wrong cobalt drill bit (or the right cobalt drill bit but using it incorrectly) is the difference between drilling 304 stainless cleanly all day and replacing burnt bits every five holes. Cobalt drill bits are not a coating. They are not "cobalt-coloured" because of a finish. The cobalt is alloyed into the high-speed steel itself — typically 5% (M35 grade) or 8% (M42 grade) — which raises the steel's hot hardness and lets the cutting edge survive the heat that ordinary HSS can't handle. That's the whole engineering story, and it's why cobalt is the standard for stainless, hardened steel, cast iron and high-tensile bolts. This guide covers what cobalt drill bits actually are, the grade differences (M35, M42, HSS-PM), the materials they're designed for, the technique that makes them last (and the technique that wastes them in five seconds), brand selection in the Australian market, and the cost reality of when cobalt pays back vs staying with premium HSS or upgrading further to solid carbide. For the broader drill bit selection guide covering all materials and bit types, see our Choosing the Right Drill Bit guide and Types of Drill Bits reference. This article focuses specifically on cobalt as a substrate choice. Need another reference chart? Browse the full AIMS Engineering Reference Charts library — drill bit sizes, tap drill, torque, viscosity, GD&T, AS/NZS standards and more. Cobalt Drill Bit Selector — Choose by Job This guide is a working selector tool — not just a reference. Use it to choose the right cobalt drill for your job. Pick your scenario below for a direct path to the right product, or scroll down for the full M35-vs-M42 grade comparison and material-by-material selection. How to use: 1. Pick your scenario 2. View the product 3. Choose your size from the variant selector Stainless Steel Drilling M35 cobalt — workshop standard Sutton D108 View → Heavy-Duty Production M42 cobalt bulk pack Sutton D109 View → 19-pc Metric Cobalt Set 1mm-10mm in case Sutton D109SM2 View → Imperial Cobalt Sizes 1/16" - 1/2" range Sutton D108 View → Hardened Steel (>30 HRC) Black Magic stub — TiAlN coated Sutton D153 View → Premium Coated Cobalt Black Magic jobber TiAlN Sutton D169 View → Browse Full Cobalt Range All sizes + grades + sets Collection View → Compare to HSS / Carbide Decision guide Selection Guide View → Cobalt drills are the right answer for stainless steel, hardened steel (up to ~50 HRC), titanium, high-tensile bolts, and anything where HSS bright drills work-harden and snap. For mild steel + occasional drilling, regular HSS is more economical (see Drill Bit Selection Guide). Need help? Call (02) 9773 0122. Jump to: M35 vs M42 vs HSS / Carbide Stainless Hardened Steel Speed/Feed/Fluid Identification Brands Cost Analysis Related Selectors AIMS Top Picks — Pick the Right Cobalt Drill Bit Cobalt (HSS-Co, typically M35 or M42) drills bridge the gap between HSS jobber and solid carbide — better than HSS on tough materials (stainless, work-hardened steel), cheaper than carbide, more forgiving on hand-held + manual machines. AIMS stocks Sutton's professional cobalt range plus Bordo value-tier cobalt. Call (02) 9773 0122 for size advice. Workshop Default — Sutton D108 Range Application AIMS recommendation Why this one Workshop default — metric sizes Sutton D108 Cobalt Jobber Metric The AU workshop standard cobalt drill. Colour-tempered for visual identification. 1.0–13.0mm metric range Imperial workshop sizes Sutton D108 Cobalt Jobber Imperial Same D108 in imperial (1/16"–1/2") — for older drawings + US machinery work Heavy duty production (bulk pack) Sutton D109 Heavy Duty Cobalt Bulk Pack D109 = upgraded cobalt content for production volume. Bulk pack pricing for fab shops Left-hand cobalt (stud extraction) Sutton D202 Left-Hand Cobalt Jobber Left-hand cut direction — for broken stud extraction. The cobalt + reverse rotation combo backs out broken bolts as it drills Bordo Value-Tier Cobalt Application AIMS recommendation Why this one Bordo 2011 series (workshop value) Bordo HSS Cobalt Jobber 2011 Series Bordo's professional cobalt range — workshop value tier vs Sutton D108. Mid-price quality Bordo 2010 series Bordo HSS Cobalt Jobber 2010 Series Entry-level Bordo cobalt — for occasional cobalt work where premium tier isn't justified When to Step Up from Cobalt to Carbide Cobalt is the right answer for ~80% of stainless, work-hardened and heat-treated steel work. Step up to solid carbide when you're doing PRODUCTION volume (50+ holes/day in tough material), or when the material is over 40 HRC (hardened tool steel, Inconel, hardened bearing steel). For carbide drilling, AIMS stocks Sutton D300/D304/D306/D310/D323 VHM TiCN/AlCrN range — see the Drill Bit Selection Guide. Buying tip from AIMS: Cobalt drill bits look identical to HSS — the cobalt is alloyed throughout, not coated. Sutton's D108/D109 use a heat-temper colour as a visual identifier. If your drill isn't colour-tempered or marked "HSS-Co" / "M35" / "M42", it's probably HSS, not cobalt. Use cobalt for stainless 304/316 (drills 2-3× longer than HSS) and for any material where HSS work-hardens. For mild steel, HSS jobber (Sutton D101/D102 Bullet) is still the more economical choice.What is a cobalt drill bit? A cobalt drill bit is a high-speed steel (HSS) drill bit with cobalt alloyed into the steel itself. The cobalt is part of the steel — not a surface treatment, not a coating. You cannot scrape the cobalt off; it is the steel. The two main cobalt grades are designated by their cobalt content: M35 grade — 5% cobalt. The standard cobalt drill bit. Significantly better than plain HSS in heat-generating cuts. The default upgrade choice from M2 HSS for stainless steel and most hardened metals. M42 grade — 8% cobalt. The premium cobalt grade. Higher hot hardness still, longer life in stainless and very hard steels. About 30–40% more expensive than M35; chosen for production-volume work or particularly demanding materials. The cobalt addition raises the steel's red hardness — the temperature at which the steel begins to soften and lose its cutting edge. Standard M2 HSS softens around 600°C; M35 cobalt holds its edge to about 650°C; M42 to about 700°C. That additional 50–100°C is the difference between cutting cleanly through stainless steel and burning the cutting edge off in three holes. Visually, cobalt drill bits typically have a duller, more golden or bronze tint than bright HSS — but colour alone is not a reliable indicator. Cheap drill bits sometimes use surface colouring to imply cobalt content that doesn't exist. The only reliable indicator is the manufacturer's marking and the brand reputation behind it. M35 vs M42 vs HSS-PM — cobalt grade selection Grade Cobalt content Red hardness Best for Cost (vs M2 HSS) M2 HSS (baseline) 0% ~600°C Mild steel, aluminium, brass, copper, plastics, timber 1× M35 (5% Co) 5% ~650°C Stainless 304/316, hardened steel to ~30 HRC, cast iron, high-tensile bolts up to grade 8.8 ~1.5–2× M42 (8% Co) 8% ~700°C Heavy stainless production, 17-4 PH, hardened steel to ~45 HRC, high-tensile bolts grade 10.9, abrasive materials ~2.5–3× HSS-PM (Powder Metallurgy HSS, e.g. ASP 2030, T15) 5–10% (varies) ~700°C, plus toughness boost Same materials as M42, plus very interrupted cuts and shock-loaded applications. Premium specialty. ~3–5× Solid carbide (next step up) — ~900°C+ Hardened steel above 45 HRC, titanium, abrasive composites, production CNC ~5–10× M2 HSS The practical selection rule: Drilling stainless 304 or 316 occasionally in a workshop? Use M35. The cost premium over M2 HSS is small; the performance gain is enormous. Production drilling in stainless, repetitive work, or material harder than 304? M42. The extra 30–40% cost is paid back many times over in tool life. Hardened steel above 45 HRC, or any application where M42 still struggles? Solid carbide. Cobalt's red hardness ceiling has been reached. HSS-PM is specialist territory — interrupted cuts in hardened material, shock-loaded applications, high-precision sharpenability. Most workshops never need it. Cobalt vs HSS, cobalt vs carbide — where each fits Three substrates, three different sweet spots. The choice isn't "best material" — it's matching the substrate to the application. Property M2 HSS M35/M42 cobalt Solid carbide Hardness ~63–66 HRC ~67–70 HRC ~89–93 HRA (≈75–80 HRC) Hot hardness ceiling 600°C 650–700°C 900°C+ Toughness (resistance to chipping) High Slightly lower than M2 Brittle — chips easily Resharpenable Yes (basic grinder) Yes (with care) Specialist regrinding only — not economical Cost (10 mm twist drill) ~$8–15 ~$15–35 (M35) or $25–50 (M42) ~$50–120 Best for Mild steel, soft non-ferrous, timber, plastics Stainless, hardened steel, high-tensile bolts, cast iron Above ~45 HRC, titanium, hardened production work Worst for Stainless (work-hardens, burns out) Above ~45 HRC (cobalt softens before cutting) Interrupted cuts (shatters), DIY hand drilling (snaps) The pattern: as you move from M2 HSS → cobalt → carbide, hardness goes up but toughness goes down. Cobalt sits in a sweet middle position — hard enough for stainless and hardened steel up to about 45 HRC, tough enough to survive hand drilling and interrupted cuts that would shatter solid carbide. For most Australian workshop drilling needs above mild steel, cobalt is the right answer. For the analogous decision on end mills, see our Carbide vs HSS End Mill deep-dive — the substrate logic is similar but the application differences (rotational drilling vs side-cutting milling) shift the breakpoints. Stainless steel: the cobalt sweet spot Austenitic stainless steel — 304 and 316, the most common AU industry grades — has one specific behaviour that defeats ordinary HSS drill bits and makes cobalt the right choice: work-hardening under heat and pressure. When a drill bit cuts stainless steel, friction generates heat at the cutting edge. The stainless steel surface beneath the cutting edge responds to this heat by becoming harder — a layer typically 0.05–0.2 mm thick that's measurably harder than the parent material. If the drill bit can't cut through this hardened layer, it rubs instead of cuts; rubbing generates more heat; more heat creates a deeper hardened layer; and the bit either burns its cutting edge off (HSS) or simply skates across a now-hardened surface. Cobalt's higher red hardness lets the cutting edge stay sharp at the temperatures that work-harden stainless. The bit cuts through the work-hardened layer faster than a new layer forms. Combined with correct technique, cobalt drills stainless cleanly. The same cobalt-HSS logic applies up the scale: for larger-diameter structural stainless holes that exceed twist drill capacity (16-50mm+), the cobalt-grade annular cutter in a magnetic drill uses the same red-hardness advantage with the same technique rules — slow RPM relative to mild steel, continuous coolant, solid steady feed, never pause mid-cut. The stainless steel work-hardening warning If you drill stainless steel at high RPM, with light pressure, or with pauses mid-hole, you create a work-hardened zone that even a premium M42 cobalt cannot drill through. The correct technique is the opposite of intuition: slow speed, firm consistent pressure, continuous cutting fluid, no pausing once started. Pecking — lifting the bit and restarting — is the classic failure mode. Once you create the hardened zone, the drill is finished and probably so is the bit. Forum reality: r/metalworking's "Can't for the life of me drill through stainless steel" thread (110+ comments) is almost entirely diagnoses of work-hardening from incorrect technique. The correct stainless steel drilling technique: Slow speed. A 6 mm cobalt bit in 304 stainless wants approximately 200–400 RPM, not 1,000+. A 12 mm bit wants 60–120 RPM. The general rule: about one-third the speed you'd run for mild steel. Firm consistent pressure. Push the bit hard enough that it's continuously cutting (chips coming off, not dust). Light pressure equals rubbing equals work-hardening. Continuous cutting fluid. Even a few drops of thread-cutting oil or dedicated stainless fluid (Trefolex, Tap Magic) makes a substantial difference in bit life and finish quality. Soluble oil also works on benchtop drilling. Don't peck or pause. Once the bit is engaged, keep cutting until the hole is through. Lifting the bit creates a perfect work-hardened ring at the depth you stopped — then the next cut hits hardened material before any fresh cutting can start. Start with a centre punch. Cobalt bits don't like wandering; a centre-punched divot keeps the bit on target from the first revolution. Use a sharp bit, not a tired one. A dull cobalt bit on stainless is just creating heat and hardening the material. Resharpen or replace. For full speeds and feeds reference across all material/bit combinations, see our Cutting Speeds and Feeds Chart. For cutting fluid selection by application, see our Cutting Fluids Guide. Hardened steel: cobalt's outer limit Cobalt drill bits handle hardened steel up to approximately 45 HRC reliably with M42 and 30–35 HRC with M35. Above that, you're approaching the cobalt ceiling and solid carbide is the appropriate next step. Material hardness Recommended substrate Notes Up to ~25 HRC (mild and medium-tensile steel) M2 HSS Cobalt is overkill — premium HSS handles this fine 25–35 HRC (high-tensile bolts grade 8.8, some heat-treated steel) M35 cobalt Standard cobalt territory 35–45 HRC (heat-treated tool steel, hardened spring steel, grade 10.9 bolts) M42 cobalt Slow speed and good fluid mandatory 45–55 HRC (hardened tool steel, dies) Solid carbide (TiAlN coated) Cobalt softens at the cutting temperatures generated; carbide handles it 55+ HRC (case-hardened surfaces, hardened bearings) Solid carbide or specialty (CBN grinding) Drilling becomes very difficult; sometimes annealing is required first The "stuck bolt" scenario. Snapped grade 8.8 bolts, broken taps, hardened studs — the classic AU workshop "I need to drill out something hard" job. Forum consensus from Practical Machinist and Reddit r/Machinists is consistent: M42 cobalt is the standard first attempt; if M42 won't bite, the bolt is harder than 45 HRC and it's solid carbide territory. For broken tap removal specifically, see our Broken Tap Removal Guide. Cast iron, high-tensile bolts and abrasive materials Beyond stainless and hardened steel, cobalt drill bits are the right choice for several other Australian-workshop materials: Cast iron — abrasive but not particularly hard. Cobalt's wear resistance pays off; the chip is short and crumbly which doesn't load the flutes. Drill cast iron dry — adding cutting fluid creates an abrasive paste that wears the bit faster than dry cutting. M35 is usually sufficient. High-tensile bolts (grade 8.8, 10.9, 12.9) — bolt grades 8.8 and above are heat-treated and run 30–45 HRC. Cobalt is the appropriate substrate; M42 for the harder grades. Drill slowly with cutting fluid, don't peck. Spring steel and music wire — heat-treated, 50–55 HRC. M42 cobalt occasionally works at very low speeds; solid carbide is more reliable. Inconel and high-temperature alloys — work-hardens severely, generates high heat. M42 cobalt is workable for one-off holes; production volume = solid carbide with appropriate coatings. Titanium and titanium alloys — low thermal conductivity means heat stays in the bit. M42 cobalt is marginal; solid carbide with AlCrN or similar coating is the standard production choice. Abrasive composites (fibreglass, carbon fibre) — pure abrasive wear regardless of hardness. Solid carbide or PCD-tipped is the long-life choice; cobalt works for small volumes. Speed, feed, and cutting fluid for cobalt Cobalt's hot-hardness advantage only delivers if you give the bit the conditions to use it. Wrong speed and feed make a $30 cobalt drill bit perform like a $5 HSS — burning out fast and leaving a rough hole. Material Cobalt cutting speed (V_c, m/min) RPM for 6 mm bit RPM for 10 mm bit Cutting fluid Stainless 304 15–22 800–1,170 480–700 Trefolex / Tap Magic / sulphurised cutting oil Stainless 316 12–18 640–960 380–570 Same — 316 needs slightly slower Hardened steel 30–40 HRC 10–15 530–800 320–480 Sulphurised oil, slow steady feed Cast iron (grey) 25–35 1,330–1,860 800–1,110 Dry — no fluid Mild steel (cobalt overkill) 30–45 1,600–2,400 950–1,430 Soluble oil or none for short jobs Aluminium (cobalt overkill but works) 60–100 3,180–5,300 1,910–3,180 WD-40 or kerosene The general rule for cobalt vs HSS speeds: cobalt runs at the same speed as HSS in mild steel, about 1.5× HSS speed in stainless (because HSS shouldn't really be used in stainless), and well below HSS speed in hardened material. Slower than you might think — many DIY drilling failures come from running cobalt at the same speed you'd use for mild steel HSS. Feed rate matters as much as speed. Light feed (low pressure on a hand drill, low feed setting on a drill press) creates rubbing rather than cutting and burns the bit. A cobalt drill bit wants firm, consistent feed pressure that produces continuous chips — a chip should be coming out of the hole every revolution. Hand drill vs drill press technique Cobalt drill bits work in both, but the technique differs. On a drill press: set the speed correctly for the material and bit diameter; clamp the work; apply firm continuous feed; use cutting fluid liberally. Drill press technique is mostly about the setup — once the speed and clamping are right, the cutting itself is straightforward. In a hand drill (battery or corded): the challenge is the operator. You need to maintain consistent feed pressure, hold the drill straight (no wobbling), and stop cleanly through the back side of the work. Hand-drilling stainless with cobalt is achievable but requires: The drill set to low speed — most cordless drills have a Hi/Lo selector. Use Lo. If yours has variable trigger, run it at maybe 30–40% trigger pull. A centre punch on the marked spot before starting (cobalt bits hate wandering) Both hands on the drill, body weight behind it, feeding firmly A squirt of cutting fluid applied before starting and re-applied if you stop No stopping mid-hole. If you must stop, lift the bit clear and re-apply fluid before continuing. Watch the chip colour. Bright silver chips = correct technique. Blue or brown chips = too much heat — slow down or apply more fluid. Hand-drilling thicker stainless (above 6 mm) with a small cobalt bit is hard work. For repetitive work in stainless, a drill press or magnetic base drill makes the job dramatically easier. Cobalt drill bit identification — markings and what to look for How to tell whether a drill bit is genuinely cobalt — and what grade: Manufacturer marking. Premium cobalt drill bits are laser-marked or stamped with the grade designation (M35, M42, HSS-Co5, HSS-Co8). Sutton, Bordo, Tivoly, Dormer, Cleveland, Triumph and other premium brands all mark their cobalt clearly. Unmarked or vaguely-marked drill bits should be assumed to be standard HSS regardless of seller claims. Standards markings. Cobalt drill bits to DIN 338 = jobber-length cobalt twist drill DIN 1869 or DIN 340 = long series cobalt DIN 1897 = stub series cobalt The DIN number is followed by the grade: HSS-Co5, HSS-Co8 Colour is unreliable. Genuine cobalt is typically a duller gold/bronze tint than bright HSS, but cheap drill bits can be artificially coloured to look the same. Don't rely on colour alone. Magnetism. Cobalt drill bits remain magnetic (it's still steel, just alloyed). Solid carbide drill bits are barely magnetic — if a "carbide" drill bit sticks to a magnet strongly, it's likely not solid carbide. Brand reputation. A Sutton-marked, Tivoly-marked or Dormer-marked cobalt drill bit is genuine cobalt at the stated grade. An unbranded or generic-branded "cobalt" drill bit on eBay or marketplace at one-third the price of premium is a quality risk regardless of marketing claims. The Practical Machinist thread "Where can you get a REAL M42 cobalt drill?" exists because so much "M42" tooling on the cheap end of the market is mis-marked. Brand selection in the Australian market Sutton Tools (manufactured in Thomastown, Victoria) — Australia's premium cobalt drill bit manufacturer. Comprehensive M35 and M42 ranges across jobber, stub and long-series formats. The standard recommendation for most Australian workshops. AIMS stocks the Sutton range — see the Sutton Tools collection. Bordo — Australian-distributed range, strong on M35 cobalt and HSS. Good value for hand-drill use and moderate workshop volumes. AIMS-stocked. Tivoly (France) — premium European cobalt manufacturer, available in AU through specialist tool distributors. Excellent quality, premium price. Dormer (UK/Sweden, now Dormer Pramet) — premium European brand with full cobalt range. Available through industrial distributors. Other premium brands available in AU on order: Cleveland (USA), Triumph (USA), OSG (Japan), Mitsubishi (Japan), YG-1 (South Korea — value premium). Avoid: unbranded cobalt drill bits on eBay, marketplace listings, or budget retailers at unrealistic prices. Forum-validated reality: cheap "M42 cobalt" sets often turn out to be standard HSS coloured to look like cobalt, or M35 sold as M42, or cobalt content well below the marked grade. A premium HSS bit ($10) typically outperforms a $5 fake-cobalt every time. Cheap "cobalt" quality variance warning Budget drill bit sets marketed as "cobalt" or "M42" frequently fail testing — wrong cobalt content, wrong grain structure, or no cobalt at all. The Practical Machinist thread "Where can you get a REAL M42 cobalt drill?" runs to many pages of disappointed buyers. If a cobalt drill bit set costs less than premium HSS, scepticism is warranted. Stick to brands you can verify: Sutton, Bordo, Tivoly, Dormer, Cleveland, Triumph, OSG, Mitsubishi, YG-1. Cost reality: when does cobalt pay back vs premium HSS? The premium for genuine cobalt over premium HSS is real but smaller than people assume: Bit (10 mm jobber, premium AU brands) Approx AU price (single bit) Multiplier M2 HSS (premium, e.g. Sutton/Bordo) ~$8–15 1× M2 HSS with TiN coating (gold) ~$12–20 ~1.3× M35 cobalt (5%, e.g. Sutton M35) ~$15–25 ~1.5–2× M42 cobalt (8%, premium) ~$25–45 ~2.5–3× HSS-PM specialty (e.g. ASP 2030) ~$40–80 ~4–5× Solid carbide (TiAlN-coated) ~$50–120 ~5–8× The payback math: A premium HSS bit drilling stainless will drill maybe 5–10 holes before the cutting edge is gone, then needs resharpening or replacement. A premium M35 cobalt in the same stainless will drill 50–100 holes before resharpening is needed. The cobalt's life is roughly 10× longer in stainless. At 1.5–2× the bit cost, cobalt pays back the upgrade cost on the second hole and everything after that is pure savings. In materials where HSS works fine (mild steel, aluminium, brass, timber), cobalt is overkill — you're paying 1.5–2× for performance you don't need. Run HSS for the easy materials and keep cobalt for stainless, hardened steel, and the genuinely hard materials. Build a mixed kit: the right Australian workshop drill bit kit is a mix — premium HSS in common sizes for general work, plus M35 cobalt in 4–10 mm sizes for stainless and hardened material work. Add M42 for production-volume stainless. Solid carbide for jobs where cobalt has reached its limit. Common mistakes that kill cobalt drill bits early Cobalt drill bits should last a long time. When they fail prematurely, it's almost always one of these mistakes: Running too fast. The most common error. Cobalt's heat-resistance advantage doesn't help if you generate so much heat that even cobalt's ceiling is exceeded. In stainless, slower than your instinct says. Pecking — lifting and restarting. Each lift creates a work-hardened ring; the next cut hits the hard ring and burns out the cutting edge. Once you start, finish. No cutting fluid. Stainless and hardened steel need fluid. A few drops of thread-cutting oil makes the difference between a bit that lasts and a bit that burns out. Light feed pressure. Rubbing instead of cutting work-hardens the material and overheats the bit. Push firmly enough to be cutting continuously. Using cobalt where HSS would do. Not a failure, just waste — you're consuming expensive bits on jobs that don't need them. Using HSS or "cobalt"-marked-cheap-bit on stainless. Burns out, gets blamed on the work, gets replaced with another cheap bit, repeats. The real fix is genuine cobalt. Drilling cast iron with cutting fluid. Counter-intuitive but true — fluid + iron dust creates abrasive paste. Drill cast iron dry. Not centre-punching. Cobalt bits wander if not started in a punch mark. Wandered bits make oversized, off-centre holes and stress the cutting edge. Letting the bit stop in the hole. Battery dying mid-cut, drill press tripping, hand drill clutch slipping — all create the work-hardening trap. Buying unverified cheap "cobalt" bits. If it's not genuine, the cobalt benefit isn't there regardless of the marking. Cobalt drill bits at AIMS Industrial AIMS stocks Sutton M35 and M42 cobalt drill bits (Australian-made), Bordo M35 cobalt, and selected premium imports. Browse the full range in our dedicated Cobalt Drill Bits collection. For other drill bit types and the broader cutting tool range: Jobber Drill Bits collection — HSS jobber-length twist drills for general metal and timber work Sutton Tools collection — full Sutton range including HSS, cobalt and solid carbide drill bits, taps, reamers and end mills Carbide Drill Bits collection — for the next-step upgrade above cobalt's limit (hardened steel above 45 HRC, titanium, abrasive composites) For specific cobalt grades, sizes, or premium imports we don't show online, call us on (02) 9773 0122 or use our contact page. We can source most premium cobalt and carbide drill bits available in the Australian market. For the broader drill bit selection guide covering all materials, see our Choosing the Right Drill Bit Guide and Types of Drill Bits reference. When a fastener won't come loose with normal effort, walk through the full escalation in our How to Remove Stuck Bolts & Nuts guide — penetrant through to drill-out and weld-on. Related AIMS Selectors This guide complements AIMS's other drilling selectors. Use them together for complete coverage: Drill Bit Size Selector — every metric drill diameter linked to AIMS-stocked SKU. Drill Bit Selection Guide — broad guide on HSS vs cobalt vs carbide for general drilling. Tap Drill Size Selector — for threading work, gives you the tap + matching drill SKU. Tap & Die Selection Guide — companion guide on tap selection (also cobalt for stainless). HSS vs Carbide End Mill — when carbide is worth the cost (same material principle as drills). Cutting Speeds & Feeds Reference — RPM and feed rate for cobalt drilling by material. Cutting Tool Materials — HSS, cobalt, carbide grades compared. Cutting Tool Coatings — TiN, TiAlN, AlCrN, when each matters for cobalt drills. Cutting Tool Troubleshooting — walking drills, oversize holes, snapped tips. Or browse the full cobalt drill bits range + jobber drill bits + reduced shank for larger sizes — Sutton primary, Bordo and P&N alternates, in stock for next-day Australia-wide dispatch from our Milperra warehouse.Frequently Asked Questions What is the difference between HSS and cobalt drill bits? Cobalt drill bits are high-speed steel with cobalt alloyed into the steel itself — typically 5% (M35) or 8% (M42). The cobalt isn't a coating; it's part of the steel. The cobalt addition raises the steel's red hardness (the temperature at which the cutting edge begins to soften) from about 600°C for plain M2 HSS to 650–700°C for cobalt grades. This extra heat resistance makes cobalt the right choice for stainless steel, hardened steel, cast iron and high-tensile bolts where ordinary HSS burns the cutting edge off in a few holes. Are cobalt drill bits worth the extra cost? For drilling stainless steel, hardened steel, cast iron, or high-tensile bolts — yes, by a wide margin. A cobalt drill bit in stainless typically lasts 5–10× longer than HSS at 1.5–2× the price, paying back the upgrade cost on the second hole. For drilling mild steel, aluminium, brass, or timber where HSS works fine, cobalt is overkill — premium HSS is a smarter spend. Build a mixed kit: HSS for general work, cobalt M35 for stainless and hardened material, M42 for production-volume hard work, solid carbide for above 45 HRC. What is the difference between M35 and M42 cobalt drill bits? M35 contains 5% cobalt; M42 contains 8% cobalt. The higher cobalt content gives M42 a slightly higher red hardness (~700°C vs ~650°C for M35), longer tool life in stainless and hardened steel, but at 30–40% higher price. For occasional stainless drilling, M35 is sufficient and cost-effective. For production-volume stainless work or hardened steel above 35 HRC, M42 pays back the cost premium through longer tool life. Above 45 HRC, both are at their limit and solid carbide is the right next step. What is the best drill bit for stainless steel? A genuine M35 or M42 cobalt jobber drill bit from a verified premium brand (Sutton, Bordo, Tivoly, Dormer), used with correct technique: slow speed (about one-third of mild steel speed), firm consistent feed pressure, continuous cutting fluid, and no pausing once started. The combination of cobalt substrate plus correct technique handles 304 and 316 stainless cleanly. Cheap "cobalt" drill bits on eBay or budget retailers frequently fail because the cobalt content is below the marked grade or absent entirely. Why does my drill bit keep burning out in stainless steel? Almost always one of: running too fast (stainless wants slow speed — about one-third of mild steel RPM); pecking (lifting and restarting creates a work-hardened zone); insufficient cutting fluid (stainless needs continuous fluid); light feed pressure (rubbing instead of cutting work-hardens the material); or using HSS instead of cobalt. The mechanism is stainless steel's work-hardening behaviour — under heat and friction the surface gets harder, and if your bit can't cut through the hardened layer faster than new layers form, it rubs and burns. Fix: cobalt M35 or M42, slow speed, firm feed, continuous fluid, no pausing. Is M42 cobalt better than carbide for hardened steel? Up to about 45 HRC: M42 cobalt is the right choice. Cobalt is much tougher than carbide and survives the interrupted cuts and slight misalignment that hand drilling creates. Above 45 HRC: solid carbide takes over because cobalt softens at the cutting temperatures generated. The crossover point depends on how hard the material is and how production-grade your setup is — for occasional hand-drill work, M42 cobalt can stretch up to 50 HRC if you go slow with fluid; for production work, carbide above 45 HRC. Can cobalt drill bits be resharpened? Yes — cobalt is just alloyed HSS, so it sharpens on the same equipment as standard HSS drill bits. A drill bit sharpener (Drill Doctor, Tradesman) handles cobalt fine; a bench grinder with the right wheel and a steady hand also works. The cutting edge geometry matters: 135° split-point is the modern standard for stainless and metal drilling, much better than the older 118° tip. Cobalt holds a sharp edge well after regrinding. The regrindability is part of the cost story — a $25 cobalt bit with two regrinds at $5 each delivers $35 total cutting capacity. Are cobalt drill bits the same as cobalt-coated drill bits? No — and the distinction matters. Genuine cobalt drill bits have cobalt alloyed into the steel itself (5% for M35, 8% for M42). The cobalt is part of the steel and stays there even after resharpening. "Cobalt-coated" or "cobalt-finish" drill bits are HSS with a thin surface treatment — the coating wears off in normal use and is gone after the first regrind. Marketing language sometimes blurs this distinction; check for the M35 or M42 grade marking, and the brand reputation, to verify genuine cobalt. What cutting fluid should I use for drilling stainless with cobalt? For stainless steel: a sulphurised cutting oil is the standard recommendation — Trefolex, Tap Magic, Rocol RTD, or similar dedicated thread-cutting and stainless drilling fluids. Even general-purpose soluble oil or a few drops of motor oil is better than nothing. For hardened steel: same — sulphurised oil. For cast iron: nothing — drill dry, fluid creates abrasive paste. For mild steel: optional, but soluble oil extends tool life. For aluminium: WD-40 or kerosene work well; never sulphurised oil (stains aluminium). See our Cutting Fluids Guide for the full breakdown. Why are some cobalt drill bits gold-coloured and others silver? The colour difference is mostly cosmetic. Bright silver/grey is uncoated genuine cobalt — the natural colour of HSS-Co. Gold-tinted cobalt bits have a thin TiN (titanium nitride) coating over the cobalt substrate, intended to add slightly more wear resistance. The TiN coating wears off the cutting edge in normal use, after which the bit performs identically to uncoated cobalt. The colour is not a reliable indicator of cobalt grade — check the manufacturer's marking (M35, M42) for the actual grade. Cheap drill bits sometimes use gold colouring to imply cobalt content that doesn't exist. Can cobalt drill bits drill through hardened bolts? Yes — that's exactly what they're designed for. Grade 8.8 high-tensile bolts run about 30 HRC; grade 10.9 about 35 HRC; grade 12.9 about 40 HRC. M35 cobalt handles 8.8 cleanly; M42 cobalt handles up to 10.9 reliably and 12.9 with care. Above grade 12.9, you're approaching solid carbide territory. Technique matters: slow speed, cutting fluid, firm feed, no pecking. For broken bolt extraction specifically (snapped studs in tapped holes), see our broken tap removal guide — same principles apply for studs. What is HSS-PM and is it worth the extra cost over M42? HSS-PM stands for high-speed steel — powder metallurgy. The steel is produced from atomised powder rather than conventional ingot casting, giving a more uniform grain structure and higher toughness at the same hardness. Common designations include ASP 2030, T15, M48-PM. HSS-PM holds an edge as well as M42 cobalt with better toughness, particularly in interrupted cuts and shock-loaded applications. The cost premium is significant — typically 3–5× M2 HSS — and most workshops will never need it. Specialist territory for production-volume hard milling and drilling. How fast should I run a cobalt drill bit? Significantly slower than you'd run HSS in mild steel. For 304 stainless with a 6 mm cobalt bit: 800–1,170 RPM. For 10 mm: 480–700 RPM. For 12 mm in 316 stainless: 320–480 RPM. For hardened steel: lower again — about half those numbers. The general rule for cobalt: about one-third the speed of mild steel for stainless, half the speed for hardened material, and same speed as HSS for mild steel and aluminium. See our Cutting Speeds and Feeds Chart for the full reference table. Are budget cobalt drill bit sets worth buying? Generally no. The Practical Machinist thread "Where can you get a REAL M42 cobalt drill?" runs to many pages of buyers reporting that budget cobalt sets test out as standard HSS or low-cobalt M35 sold as M42. The cost saving is real (~30–50% off premium prices) but tool life is often half or less of premium cobalt — wiping out the saving on the first major job. A premium M35 from Sutton, Bordo, Tivoly or Dormer at $15–25 is a smarter spend than a $40 unbranded "M42" set with 13 sizes that may or may not actually be cobalt. Quality variance in cheap drill bit sets is huge; brand reputation is the only reliable check. What is a "split point" cobalt drill bit and why does it matter? A split-point drill bit has a small secondary cutting edge ground into the chisel point at the tip — converting the chisel from a wedge that pushes material aside into a cutting edge that cuts material away. The split point is sharper, starts cleanly without wandering, and reduces feed pressure required. For stainless steel and hardened material drilling, 135° split-point geometry is the standard recommendation — it cuts cleanly with less heat generation than the older 118° tip. Most premium cobalt drill bits come split-point as standard. If you're choosing between split-point and standard 118° cobalt for stainless work, choose split-point. For complete metric bolt sizing (M3-M24) with thread pitch and head dimensions, see our Metric Bolt Size Guide. Need sutton tools? Browse the AIMS range at sutton tools.
Read moreCarbide vs HSS End Mill: When to Upgrade
"Should I upgrade my HSS end mills to carbide?" is one of the most-asked questions in any workshop, and one of the most poorly answered. The default response — "carbide is faster and lasts longer" — is true but incomplete. Carbide is faster only if your machine can run it fast. It lasts longer only if you don't break it. And in some specific applications, HSS still wins outright. This article gives you the honest decision framework: when carbide pays for itself, when HSS still beats carbide, the spindle-RPM threshold that decides most cases, the regrinding economics that get missed in every cost comparison, and the cobalt HSS bridge-upgrade that's often the right answer for jobs where neither pure HSS nor solid carbide quite fits. For the broader end mill selection guide — types, flute count, coatings, feeds and speeds — see our parent End Mill Guide. This article focuses specifically on the substrate upgrade decision. HSS vs Carbide End Mill — Quick Decision This article is a working decision tool — not just a comparison. Use the scenarios below to land on the right answer fast, or scroll down for the full cutting speed / tool life / cost-per-cut analysis. How to use: 1. Match your job profile 2. View the right range 3. If still unsure — call us for setup-specific guidance Manual / Light Workshop Standard HSS is enough HSS Standard View → CNC Production (Steel) Solid carbide pays back fast Solid Carbide View → Stainless / Tough Material Cobalt HSS bridge before carbide HSS-Co Bridge View → Aluminium / Non-ferrous HSS still wins on cost HSS View → Hardened Steel (>30 HRC) Solid carbide AlCrN coated Carbide View → Roughing / High MRR Carbide with corn-cob geometry Roughing Carbide View → Browse Square End Mills Most common shape Square View → Browse Ball Nose End Mills 3D contour work Ball Nose View → The short answer: HSS for hobby + light workshop + non-ferrous + low-volume; solid carbide for CNC production + tough materials + when machine rigidity supports the higher cutting speeds. Cobalt HSS is the bridge step — premium HSS performance at HSS cost. Read the cost-per-cut maths below before deciding. Need help? Call (02) 9773 0122. Jump to: What's Different Cutting Speed Tool Life Cost-per-Cut RPM Threshold When HSS Wins When Carbide Wins Cobalt Bridge Decision Framework Related Selectors Cutting speed comparison — the order-of-magnitude difference — Quick Reference Cutting speed (V_c) is the speed at which the cutting edge passes through the work material, expressed in metres per minute. It's set by the combination of work material and tool material, and it's where carbide makes its claim. Work material HSS V_c (m/min) Cobalt HSS V_c Solid carbide V_c (uncoated) Solid carbide V_c (TiAlN coated) Mild steel (1018, AS 1020) 20–30 25–35 120–180 200–280 Stainless 304 15–20 18–25 80–120 120–180 Stainless 316 12–18 15–22 70–110 110–160 Aluminium 6061 60–120 80–150 250–600 (coatings not used on Al) Cast iron (grey) 20–30 25–35 120–200 180–250 Hardened steel (≤45 HRC) Not recommended 10–15 30–50 50–100 The short answer If you run a modern CNC machining centre with spindle speeds of 6,000 RPM or more, production volume justifies tooling spend, and you cut steel, stainless or hardened materials — carbide. Cycle times drop dramatically, tool life improves, and the upgrade pays for itself fast. If you run a manual mill, a step-pulley CNC retrofit with limited RPM, hobby CNC, or you do batch work with frequent interrupted cuts, deep slotting in tough material, or weld removal — HSS or cobalt HSS. The carbide speed advantage doesn't materialise on a slow spindle, and the brittleness penalty hurts on tough cuts. Most Australian workshops sit somewhere in between, and the right answer is usually a mixed kit: carbide for high-volume production CNC work, cobalt HSS for stainless and harder materials at moderate speeds, and plain HSS for hand mills, hobby work, and any job where breakage cost is high. The rest of this article gives you the framework to make that decision for your specific situation. What's actually different between HSS and carbide The headline differences are hardness and heat resistance: Property HSS (high-speed steel) Cobalt HSS (M35, M42) Solid carbide (tungsten carbide) Hardness ~63–66 HRC ~67–70 HRC ~89–93 HRA (~75–80 HRC equivalent) Heat resistance ~600°C ~700°C ~900°C+ (with appropriate coating) Brittleness Tough — bends or yields under shock Tougher than HSS at higher hardness Brittle — chips and shatters under shock Cutting speed (mild steel) ~25 m/min ~30 m/min ~150–250 m/min Reground at home? Yes, with the right grinder Yes No (specialist regrinding only, not economical) Cost (10 mm 4-flute) ~$15–30 ~$25–45 ~$50–90 (premium); ~$15 (cheap unbranded) The implications matter more than the numbers. Carbide's higher hardness and heat resistance let it cut at 6–10× the speed of HSS — but only if the machine spindle can spin fast enough to deliver that speed. Carbide's brittleness means a single hard inclusion or interrupted cut that HSS would absorb will shatter the cutting edge — making it expensive in environments where HSS is forgiving. Carbide cannot economically be reground; HSS can be reground 2–5 times before disposal, which substantially affects total cost of ownership. For a deeper material-by-material breakdown of substrates including ceramic, CBN and PCD, see the substrate section in our End Mill Guide. Cutting speed comparison — the order-of-magnitude difference Cutting speed (V_c) is the speed at which the cutting edge passes through the work material, expressed in metres per minute. It's set by the combination of work material and tool material, and it's where carbide makes its claim. Work material HSS V_c (m/min) Cobalt HSS V_c Solid carbide V_c (uncoated) Solid carbide V_c (TiAlN coated) Mild steel (1018, AS 1020) 20–30 25–35 120–180 200–280 Stainless 304 15–20 18–25 80–120 120–180 Stainless 316 12–18 15–22 70–110 110–160 Aluminium 6061 60–120 80–150 250–600 (coatings not used on Al) Cast iron (grey) 20–30 25–35 120–200 180–250 Hardened steel (≤45 HRC) Not recommended 10–15 30–50 50–100 Carbide is roughly 6–10× faster than HSS in steel, and significantly faster in aluminium. The catch: those V_c values translate to RPM via the formula RPM = (V_c × 1,000) ÷ (π × D) where D is the cutter diameter in mm. A 10 mm carbide end mill in mild steel at V_c = 200 m/min wants 6,366 RPM. If your spindle tops out at 4,000 RPM, you cannot reach the carbide speed — you're forced to run carbide at HSS-equivalent RPM, where carbide loses its advantage. For full speeds and feeds reference tables across all materials and tool combinations, see our Cutting Speeds and Feeds Chart. Tool life ratios — under matched running conditions Carbide tool life is typically 3–10× that of HSS when both are run at their correct speeds and feeds in the same material. The wide range reflects how much work-material, machine rigidity, and operator skill affect the result. Application HSS typical tool life Carbide typical tool life Ratio Mild steel, light cuts, well-lubricated 30–60 minutes cutting time 120–300 minutes ~4–5× Stainless 304, heavy cuts 15–30 minutes 90–240 minutes ~6–8× Aluminium, finishing pass 1–4 hours 4–20 hours ~5× Hardened steel Not viable 30–90 minutes — Interrupted cut (welds, scale, bolt-down clearance) Reasonable Often immediate breakage HSS often wins The ratio is real — but only if the running conditions match the tool. A carbide end mill run at HSS speeds wears at HSS rates (or worse, glazes and rubs because the chip load is wrong). A carbide end mill in interrupted cuts can fail catastrophically — chipping or shattering — where an HSS end mill would have rolled with the punch. The "carbide lasts longer" claim assumes the operator runs it correctly. Many do not. Cost-per-cut — the worked example Tool cost per cubic metre of material removed is the honest comparison. Tool price ÷ life = cost per minute. Cost per minute × time per cubic metre = cost per cubic metre. Worked example: 10 mm 4-flute end mill, mild steel, side milling at 50% radial engagement. HSS scenario: Tool cost: $25 (premium HSS, e.g. Sutton) Tool life: 45 minutes cutting time (mild steel at correct V_c) Spindle: 800 RPM (V_c = 25 m/min) Feed: 100 mm/min (chip load 0.03 mm/tooth) Material removal rate: ~5,000 mm³/min Total volume per tool life: 225,000 mm³ (0.225 cubic metres ÷ 1,000) Cost per cubic centimetre: $25 / 225 cm³ = ~$0.11/cm³ Carbide scenario (running at correct speed): Tool cost: $70 (premium carbide TiAlN, e.g. Sutton VHM) Tool life: 240 minutes cutting time Spindle: 6,400 RPM (V_c = 200 m/min) Feed: 1,500 mm/min (chip load 0.06 mm/tooth) Material removal rate: ~75,000 mm³/min Total volume per tool life: 18,000,000 mm³ (18 cubic metres ÷ 1,000) Cost per cubic centimetre: $70 / 18,000 cm³ = ~$0.004/cm³ Result: carbide is ~28× cheaper per cubic centimetre of material removed when both are run at their correct conditions. Plus the cycle time is 15× shorter, so labour cost per part drops dramatically. This is the case for carbide in production work. But: if your spindle tops out at 2,000 RPM (V_c = 63 m/min on 10 mm), the carbide is being run at 1/3 of its design speed. Tool life drops to maybe 90 minutes. Material removal rate drops to maybe 25,000 mm³/min. Now: $70 / 2,250 cm³ = $0.031/cm³ — still better than HSS, but the advantage is much smaller, and you've spent the upgrade money for a fraction of the benefit. The RPM threshold — when carbide pays back vs when it doesn't The honest threshold: Carbide makes economic sense when your machine spindle can deliver close to the carbide design RPM for your common cutter sizes. As a rough Australian-workshop rule of thumb: 3,500 RPM minimum at 10 mm cutter for steel work; 6,000 RPM ideal. Below 2,500 RPM at 10 mm, you're running carbide on an HSS speed schedule and most of the upgrade cost is wasted. Step-pulley Bridgeport-style mills, hobby CNC routers with sub-2,000 RPM spindles, and old manual mills are typically not the right machines for solid carbide tooling. The thing forum posters consistently warn about — and that competitor articles consistently miss — is that the carbide speed advantage assumes the operator can deliver the correct spindle RPM. Practical Machinist's "Bridgeport: real truth on Carbide vs HSS" thread runs to many pages with the same conclusion: on a step-pulley Bridgeport, carbide rarely makes sense. On a knee mill with a VFD-driven spindle to 6,000+ RPM, carbide makes sense. Know your machine before you spec the tool. When HSS still wins Specific scenarios where HSS or cobalt HSS beats solid carbide: Manual mills with limited spindle speed. Bridgeport and clones, Hercus, Pacific, smaller Asian mills. If max spindle is below ~3,000 RPM at 10 mm cutter, HSS typically wins on cost per cut. Interrupted cuts. Machining through welds, scale, casting flash, or across bolt holes. Each impact stresses a brittle carbide edge; HSS rolls with the impact. Heavy slotting in tough material. 4–5×D deep slot in stainless. The vibration and chip evacuation pressure is high; carbide breakage probability is high. HSS forgives. Hobbyist and one-off work. If a $50 carbide end mill might break on the third part, the hobby economics don't work. A $25 HSS will outlive the hobby project even at slower speeds. Very small diameters (1–3 mm). Small-diameter carbide is fragile; HSS at the same size is much more forgiving on mistakes. Roughing operations where surface finish doesn't matter. Roughing HSS end mills (corn-cob serrated) at moderate speed remove material reasonably well and tolerate the random impacts of rough stock. Carbide can outdo them in production CNC; in a one-off setting they often equal out. Aluminium on a hobby CNC router. A 2-flute HSS end mill in aluminium at a few thousand RPM can match or beat a poorly-cooled carbide on the same machine. Cool the cutter, take light passes, regrind the HSS later. Where breakage cost is high. One-off complex parts where a broken carbide cutter could ruin the part — HSS is the safer specification. When carbide is the obvious upgrade The other side of the decision: Production CNC machining. Cycle time matters. The 6–10× speed advantage of carbide directly reduces machining hours per part. The tooling cost is a small fraction of the labour saving. Stainless steel. Stainless work-hardens under tool friction. Carbide at correct speed cuts cleanly; HSS at HSS speed often glazes the work surface and accelerates wear in a feedback loop. Cobalt HSS bridges the gap if carbide isn't an option. Hardened steel (40+ HRC). HSS cannot reasonably cut hardened material. AlCrN-coated solid carbide is the standard choice up to about 55 HRC; for above that, ceramic or CBN. Titanium and high-temp alloys. The heat doesn't transfer well to the chip; the cutter sees high temperature. Carbide handles it (with the right coating); HSS softens at the temperatures generated. Modern CNC machining centres. 8,000–15,000 RPM spindles, rigid tool holders (hydraulic, shrink-fit, ER collets at maximum torque), high-pressure flood coolant. Built for carbide. HSS in this environment is leaving capacity on the table. High-volume aluminium production. Carbide in aluminium with the correct (uncoated polished or DLC) finish is hard to beat. The cycle times and tool life justify the upgrade easily. Where surface finish matters. Carbide at correct speed and chip thinning produces better surface finish than HSS at HSS speed. For finish passes, carbide. The cobalt HSS bridge — when an HSS upgrade beats a carbide jump Cobalt HSS — designated M35 (5% cobalt) and M42 (8% cobalt) — sits between plain HSS and solid carbide. It runs about 25–30% faster than plain HSS, holds an edge in heat-generating cuts (stainless, abrasive materials), and is dramatically less brittle than carbide. The cobalt sweet spot: Stainless steel work on a manual or moderate-RPM CNC. Plain HSS struggles; carbide is overkill or the spindle won't run it. Cobalt M35 in TiAlN coating runs cleanly at ~28 m/min in 304. Hard or abrasive materials at HSS speeds. M42 at HSS speed lasts roughly 2× plain HSS in tough materials. Moderate production where carbide breakage risk is real. A cobalt end mill is more forgiving than carbide while still outperforming plain HSS on tool life. Drilling and reaming applications where rigidity is the constraint, not speed. If your machine cannot fully run carbide and you're considering an upgrade from plain HSS, look at cobalt HSS first. The upgrade cost is much smaller, the brittleness penalty is much smaller, and the gains are real. Sutton, Bordo and Champion all stock M35/M42 cobalt end mills. For the equivalent decision on cobalt drill bits (different application — drilling stainless, hardened bolts and cast iron), see our Cobalt Drill Bit Guide. Total cost of ownership — regrinding, breakage, tool changes The headline cost ratios miss three significant factors: 1. Regrinding. Plain HSS end mills can be reground 2–5 times before being scrapped. Each regrind restores most of the original cutting performance for a fraction of the new-tool cost (~$8–15 per regrind for a 10 mm 4-flute, depending on the regrind shop). A $25 HSS end mill at four regrinds delivers $25 + 4×$10 = $65 of total cutting capacity. A $70 carbide end mill cannot economically be reground (the cost approaches new-tool cost) and is replaced when worn. Over many cycles, HSS cost-per-edge gets very competitive. 2. Breakage probability. Cheap carbide breakage is a real problem (especially on small diameters and interrupted cuts). A budgetary "we'll use cheap unbranded carbide" plan often delivers high breakage rates that wipe out the cost advantage. Premium carbide (Sutton VHM, Sandvik, Iscar) has much lower breakage probability — but at the price premium that erodes the cost-per-cut advantage. Plain HSS rarely breaks unless severely abused. 3. Tool change time. A snapped tool mid-cycle is downtime. On a low-volume manual mill, that's ten minutes of disruption. On a CNC pallet-fed machining centre, that's the part scrapped, the cycle interrupted, and possibly machine collision damage. The "soft-fail" behaviour of HSS (it gets dull, you notice, you swap it on a tool-change interval) is operationally simpler than the "hard-fail" behaviour of carbide (it works perfectly until it shatters at hour two of an unattended overnight run). Total cost of ownership, honestly assessed: in a high-volume CNC production environment, carbide still wins by a wide margin. In low-volume jobbing and manual work, HSS often wins on the soft-fail benefit alone. Premium HSS vs cheap carbide — the quality variance trap Watch out for cheap unbranded carbide. Carbide quality varies dramatically with manufacturer. A premium Sutton VHM at $70 and an unbranded eBay carbide at $15 might look identical. The premium tool will run at design speed, hold dimensional accuracy, and last 200+ minutes in steel. The cheap one might not even be solid carbide (some are HSS with carbide tips), might have sub-spec coating, will break the first time stressed, and may not run dimensionally true. A premium HSS often outperforms cheap carbide — better tool life, better surface finish, better dimensional accuracy. If budget rules out premium carbide, premium HSS or cobalt HSS is the smarter spend. Reddit r/hobbycnc threads on Chinese carbide end mills consistently report inconsistent quality: some last hours, others lose their edge in minutes, in the same batch. r/Machinists "Chinese carbide endmills lose edge" thread runs to 60+ comments documenting the variance. The lesson is not "all cheap carbide is bad" — many work fine for hobby duty — but to budget for replacement at higher rates and not expect production-grade reliability. The upgrade decision framework Run through the checklist for your specific situation: Question Answer pushes you toward Does your spindle reach 6,000+ RPM at 10 mm cutter? Yes → carbide. No → cobalt HSS or HSS. Are most of your cuts continuous (closed pockets, full-engagement profiling)? Yes → carbide. No (interrupted) → HSS. Do you machine stainless, hardened steel, or titanium? Yes → carbide (or AlCrN-coated). No → HSS may suffice. Are you running production volumes with cycle time as the constraint? Yes → carbide. No (low volume jobbing) → HSS-friendly. Is breakage cost high (long-cycle parts, attended one-offs)? High → HSS for safety. Low → carbide is fine. Is your budget for tooling tight? Yes → premium HSS or cobalt beats cheap carbide. Yes with capacity → premium carbide for production-relevant cutters only. Are you a hobbyist or new to machining? HSS for forgiveness; upgrade specific carbide later as needs become clear. Most Australian workshops end up with a mixed kit: 4-flute carbide TiAlN-coated in 6, 10, 12 mm for production CNC steel and stainless 3-flute carbide uncoated or ZrN in 6, 10 mm for production aluminium Cobalt HSS in 6, 10, 12 mm for stainless and harder materials on moderate-RPM machines Plain HSS in 4, 6, 8 mm for hand mill work, hobby use, interrupted cuts, deep slotting where breakage cost is high The mixed kit beats either pure-HSS or pure-carbide in most real workshops. Match the tool to the job rather than buying one substrate for everything. End mills at AIMS Industrial AIMS stocks both HSS and carbide end mill ranges — Sutton (Australian-made, both HSS and VHM solid carbide), Bordo (HSS and cobalt focus), plus premium imports on order. See our End Mills & Milling Cutters collection for what's in stock, or call us on (02) 9773 0122 for sizes and specifications not shown online. For the broader end mill selection guide — types, flute count, coatings, applications — see our End Mill Guide. For full speeds and feeds reference, see our Cutting Speeds and Feeds Chart. Related AIMS Selectors This decision article pairs with AIMS's other cutting-tool selectors: End Mill Guide — companion buyer guide on geometry, flute count, coatings, applications. Cobalt Drill Bit Guide — same material principle as drill bits (M35/M42 cobalt = bridge between HSS and carbide). Drill Bit Selection Guide — broader guide on HSS vs cobalt vs carbide for drilling. Cutting Speeds & Feeds Reference — Vc and feed rate per material × tool material × diameter. Cutting Tool Materials Guide — HSS, cobalt, carbide, PCBN, PCD compared in depth. Cutting Tool Coatings Guide — TiAlN, AlCrN, Helica when each matters. Cutting Tool Troubleshooting — chipped edges, vibration, snapped tools. Tap Drill Size Selector — for threading work after milling. Or browse the full end mills range, square end mills, ball nose end mills, corner radius end mills — Sutton + Bordo HSS and solid carbide options in stock for next-day Australia-wide dispatch from our Milperra warehouse.Frequently Asked Questions Are carbide end mills always better than HSS? No. Carbide is faster and lasts longer than HSS in continuous production cutting at correct speeds and feeds — which means a CNC spindle running 6,000+ RPM. In manual mills with limited spindle speed, interrupted cuts (welds, casting scale), small diameters, hobbyist work, or where breakage cost is high, HSS or cobalt HSS often beats carbide on real-world cost per cut. The right answer depends on your machine, application and volume — not on which substrate is "better" in the abstract. Is HSS stronger than carbide? HSS is significantly tougher (less brittle) than carbide. Carbide is harder. Hardness and toughness are different properties — hardness resists wear, toughness resists shock. Carbide's higher hardness means it cuts faster and lasts longer in continuous cuts; HSS's higher toughness means it survives interrupted cuts, hard inclusions, and operator mistakes that would shatter carbide. For shock-loaded cutting (welds, scale, deep slotting in tough material), HSS is the more durable choice. At what spindle RPM does carbide start paying off? As a rule of thumb: carbide makes economic sense when your machine can deliver the correct cutting speed for your common cutter sizes. For 10 mm cutters in steel that means roughly 3,500 RPM minimum, 6,000 RPM ideal. Below 2,500 RPM at 10 mm in steel, you're running carbide at HSS-equivalent speeds — most of the upgrade cost is wasted. Step-pulley manual mills with sub-3,000 RPM are typically not the right machines for solid carbide tooling. When should I use HSS over carbide? Use HSS when: your machine spindle is below ~3,000 RPM at 10 mm cutter; your cuts are interrupted (welds, scale, bolt holes); you're doing deep slotting in tough material where carbide breakage risk is high; you're a hobbyist or doing one-offs where breakage cost matters; you're cutting very small diameters (1–3 mm) where carbide is too fragile; or your budget rules out premium carbide and only cheap unbranded carbide is affordable. In any of these scenarios, premium HSS or cobalt HSS often beats budget carbide on real-world performance. Can I run carbide at HSS speeds? Yes, you can — but you waste most of the carbide advantage. At HSS speeds (one-third of carbide's design speed), the carbide cutting edge isn't generating enough heat to flow chips correctly, may glaze and rub instead of cut, and tool life drops far below carbide's potential. Cost-per-cut on a slow-running carbide is similar to HSS at far higher tool cost. If your spindle can't run carbide fast, stick with HSS or cobalt HSS — you'll get better results at lower tool cost. How much longer does carbide last vs HSS? Under matched conditions (each tool run at its correct speed in the same material), carbide typically lasts 3–10× longer than HSS. The wide range reflects work material, machine rigidity, and operator skill. In mild steel, expect roughly 4–5× life for premium carbide vs premium HSS. In stainless, 6–8×. In aluminium, around 5×. In hardened material, HSS isn't viable and the comparison doesn't apply. The ratio is real — but only when carbide is actually run at carbide speeds. What is cobalt HSS and where does it fit? Cobalt HSS — designated M35 (5% cobalt) or M42 (8% cobalt) — is high-speed steel alloyed with cobalt for higher hot hardness. It runs about 25–30% faster than plain HSS, holds an edge longer in heat-generating cuts (stainless, abrasive materials), and is dramatically less brittle than carbide. Cobalt HSS sits in the upgrade gap between plain HSS and solid carbide. It's the right choice for stainless work on a manual or moderate-RPM CNC, hard or abrasive materials at HSS speeds, and moderate production where carbide breakage risk is a concern. Often the smarter upgrade than jumping straight to carbide. Can HSS end mills be reground? Yes — most plain HSS end mills can be reground 2–5 times before being scrapped, restoring most of the original cutting performance each time. Specialist tool grinders charge around $8–15 per regrind for a 10 mm 4-flute. Over four regrinds, a $25 HSS end mill delivers around $65 of total cutting capacity. Carbide cannot economically be reground in most cases — the regrind cost approaches new-tool cost, and most carbide is replaced rather than reground. The regrindability of HSS is a real total-cost-of-ownership advantage that doesn't appear in tool-price comparisons. Is cheap carbide better than premium HSS? Often no. Carbide quality varies dramatically with manufacturer — premium brands (Sutton VHM, Sandvik, Iscar, Mitsubishi) deliver consistent design-speed performance and full tool life; cheap unbranded carbide can fail at any rate, may not even be solid carbide (some are HSS with carbide tips), and often has sub-spec coating. A premium HSS end mill ($25–30) typically beats cheap unbranded carbide ($15) on tool life, surface finish, and dimensional accuracy. If budget rules out premium carbide, premium HSS or cobalt HSS is the smarter spend. What end mill should I use for interrupted cuts? HSS or cobalt HSS — not solid carbide. Interrupted cuts (machining through welds, casting scale, across bolt holes, on rough-cast surfaces) hammer the cutting edge with repeated impacts. Carbide is brittle and chips or shatters under impact loading. HSS is much tougher and rolls with the punches. The exception: indexable carbide insert tooling specifically designed for interrupted cutting (impact-grade inserts) can handle interrupted cuts well, but solid carbide end mills generally cannot. Why do my carbide end mills keep breaking? Common causes: running too fast or too aggressively into rough or hardened material; interrupted cuts that shock-load the brittle carbide; tool stick-out too long (deflection-driven snap); incorrect speeds and feeds (especially under-feeding at low radial engagement, causing the cutter to rub and overheat); cheap unbranded carbide quality; insufficient rigidity in machine, work-holding, or tool-holding; or machining hardened material above the carbide's grade rating. If breakage is repeated, drop spindle speed and feed, check setup rigidity, verify cutting fluid flow, and consider switching to cobalt HSS for the application — particularly if cuts are interrupted. What's the cost difference between HSS and carbide? Premium HSS 10 mm 4-flute: ~$15–30. Cobalt HSS: ~$25–45. Premium solid carbide TiAlN-coated: ~$50–90. Cheap unbranded carbide: ~$15 (with quality risk). The cost ratio at first purchase is roughly 3:1 carbide-to-HSS at the premium end. The cost-per-cut ratio in production conditions can be 25:1 in favour of carbide — but only when run at design speed. In low-RPM applications, the cost-per-cut gap closes substantially. Factor in regrindability of HSS and breakage risk of cheap carbide for the honest total-cost picture. For the drive-ratio formula and worked RPM examples, see our Pulley Speed Ratio Calculator guide. Need corner radius end mills? Browse the AIMS range at corner radius end mills. What brands does AIMS recommend for premium solid carbide end mills? Premium brands including Sutton VHM, Sandvik, Iscar and Mitsubishi deliver consistent design-speed performance and full tool life, unlike cheap unbranded carbide which can fail at any rate and may not even be genuine solid carbide. How much faster can cobalt HSS run compared to plain HSS? Cobalt HSS (M35 at 5% cobalt, or M42 at 8% cobalt) runs about 25-30% faster than plain HSS and holds an edge longer in heat-generating cuts such as stainless and other abrasive materials. Does carbide's cost-per-cut advantage hold up at low spindle speeds? No. The cost-per-cut ratio in production conditions can favour carbide by as much as 25:1 — but only when the tool is run at its correct design speed. In low-RPM applications, that cost-per-cut gap closes substantially, eroding much of carbide's economic advantage. Why can't carbide end mills be economically reground like HSS? Carbide cannot economically be reground in most cases — the regrind cost approaches the cost of a new tool, so most carbide end mills are replaced rather than reground, unlike HSS which can typically be reground 2-5 times.
Read moreEnd Mill Guide: Geometry, Coatings & Selection
End mills are the workhorses of milling — whether you're running a CNC machining centre, a manual knee mill, or a benchtop hobby CNC. They cut on the side and the end, take material away in three dimensions, and live or die on getting the right combination of geometry, material, coating, flute count, and feed and speed for the job. Get the choice right and an end mill will make hundreds of parts. Get it wrong — most often the wrong coating for the work material, or the wrong flute count for the depth of cut — and you'll burn through tools, get poor surface finish, or pull the cutter in two. This guide walks through every variable that matters: types and geometry, HSS vs cobalt vs carbide, coatings (and the AlTiN-on-aluminium trap that catches plenty of beginners), flute count rules, helix angle, climb vs conventional milling, speeds and feeds, applications, failure modes, and a practical starter set for an Australian workshop. AIMS stocks 50+ end mills across square, ball nose, corner radius, corner chamfer and milling cutter ranges — Sutton (made in Australia), Bordo, and premium imports. Browse our End Mills collection for what's in stock, or read on for how to choose. Bookmark our Engineering Reference Charts hub for related sizing tables, conversion charts and Australian standard references across 9 topic clusters. End Mill Selector — Choose by Operation This guide is a working selector tool — not just a reference. Use it to choose the right end mill for your operation. Pick your scenario below for a direct path to the right tool family, or scroll down for the full geometry / material / coating analysis. How to use: 1. Pick your operation 2. View the range 3. Choose diameter, flute count and material from the collection General Slotting / Profiling Universal — most common shape Square View range → 3D Contours / Mould Work Spherical tip — smooth surface Ball Nose View range → Stronger Corners Reinforced corner — less chipping Corner Radius View range → Chamfering / Edge Break Angled tip — 45°, 60° etc. Corner Chamfer View range → Production Carbide VHM 3xD or 5xD — long life Solid Carbide View range → Workshop HSS Cheaper, easier to regrind HSS / HSS-Co View range → Indexable / Insertable Replaceable carbide inserts Indexable View range → Roughing / High MRR Corn-cob teeth — fast stock removal Roughing View range → Sutton dominates the AIMS end mill range — Black Magic carbide (Helica coating), Premium VHM, HSS roughing and finishing series. Bordo for HSS general-purpose. Need help selecting? Call us on (02) 9773 0122. Jump to: Geometry Material Flutes Helix Angle Coatings Milling Direction Starter Set Related Selectors AIMS Top Picks — Pick the Right End Mill Fast Sutton's E-series end mill range is AIMS's depth pick — solid carbide VHM (Vollhartmetall), cobalt HSS, and specialty coatings (TiAlN, AlCrN, Helica, Alnova). Recommendations below by material × job. Open the linked product to choose diameter (3mm–25mm) and flute count. Call (02) 9773 0122 for sizing help. For Mild Steel (Workshop Default) Job Geometry AIMS recommendation Why this one General slotting + contour 2-flute slot drill, HSS-Co Sutton E100 8% Cobalt Slot Drill Workshop HSS-Co default — cheaper than carbide, forgiving on manual machines. 8% cobalt for steel work Production slotting + contour 2-flute slot drill, VHM Sutton E600 2-Flute VHM Slot Drill Solid carbide (VHM) — 4-5× tool life of HSS-Co at higher cutting speeds. Production CNC default Side milling + profile (4-flute) 4-flute VHM TiAlN Sutton E604 4-Flute VHM TiAlN 4-flute for better finish + tool life on profile work. TiAlN coating for steel cutting heat resistance 2-flute end mill (not slot drill) 2-flute VHM TiAlN Sutton E603 2-Flute VHM TiAlN 2-flute end mill with TiAlN — better than slot drill for chip clearance in deeper pockets Heavy roughing (high MRR) Roughing 8% Cobalt Sutton E146 Roughing Endmill 8% Cobalt Knuckle-tooth roughing geometry — fastest stock removal on mild steel before finishing pass For Stainless Steel & Hardened Steel Job Geometry AIMS recommendation Why this one Stainless workshop (general) 4-flute VHM TiAlN Sutton E604 4-Flute VHM TiAlN TiAlN coating for stainless heat resistance — workshop standard for 304/316 work Hardened steel (>30 HRC) 4-flute VHM AlCrN Sutton E535 VHM Ultra AlCrN Long AlCrN coating for >800°C heat resistance — for hardened tool steel + heat-treated parts Hardened steel short reach 4-flute VHM AlCrN short Sutton E533 VHM Ultra AlCrN Short Short version of E535 — rigidity for tighter tolerance on hardened steel Premium tool steel work Helica VHM Sutton E459 VHM Helica Helica coating — premium for tool steel, mould steel, P20 plate work For Aluminium & Non-Ferrous Job Geometry AIMS recommendation Why this one Aluminium chip-clearing (1-flute) 1-flute VHM Ultra short Sutton E444 1-Flute VHM Ultra Single flute for aggressive chip evacuation in aluminium. The "won't gum up" choice 3-flute aluminium production 3-flute Harmony Sutton E480 3-Flute Carbide Harmony Pferd Harmony 3-flute — balanced chip clearance + finish for production aluminium For Ball Nose (3D Contouring) Job Geometry AIMS recommendation Why this one 3D contour workshop default 4-flute VHM ball nose Sutton E606 4-Flute Ball Nose VHM 4-flute ball nose — workshop default for 3D mould + contour work Steel 3D contour (coated) 4-flute VHM TiAlN ball nose Sutton E607 4-Flute Ball Nose TiAlN TiAlN-coated ball nose for harder steel contour work Slotting 3D form (ball nose) 2-flute ball nose slot drill Sutton E605 2-Flute Ball Nose TiAlN Ball nose slot drill — for full-width 3D plunging + ramping Deep pocket 3D contour 4-flute ball nose extra long Sutton E320 Ball Nose Extra Long Extra-long reach for deep mould + die work For Corner Radius & Chamfer (Tool Life Booster) Job Geometry AIMS recommendation Why this one Corner radius (general) 4-flute corner radius VHM Sutton E462 R0.3 VHM Helica Long R0.3 corner radius — eliminates corner stress concentration. 5× tool life vs square corner Premium corner radius (AlCrN) 4-flute corner radius VHM AlCrN Sutton E559 Corner Radius VHM Ultra AlCrN AlCrN + corner radius — for hardened steel mould + die work 5-flute premium 5-flute Alnova HA Sutton E466 5-Flute Alnova HA 5-flute = better finish + tool life on production work. Alnova premium coating Chamfer end mill (corner radius combo) 4-flute chamfer + corner radius Sutton E458 Chamfer + Corner Radius VHM TiAlN Combo geometry — chamfer edge + corner radius in one tool. Saves a setup Buying tip from AIMS: Sutton's Australian-made VHM (solid carbide) range is the workshop standard for AU machining. Match coating to material: TiAlN for general steel, AlCrN for hardened + heat-stable, Helica for premium tool steel, Alnova for high-end. For aluminium, never use TiAlN (chemical reaction causes premature wear) — use uncoated VHM or specific aluminium coatings. 4-flute = better finish, 2-flute = better chip clearance for slotting, 1-flute = maximum chip clearance for aluminium.What is an end mill? An end mill is a rotary cutting tool designed for milling — removing material from a workpiece by feeding it sideways past a rotating cutter. Unlike a drill bit (which only cuts on its tip and is designed to plunge straight down), an end mill cuts on both its end and its sides, allowing it to take side cuts, profile shapes, slot, ramp, and machine in three dimensions. The basic anatomy is straightforward: a cylindrical shank that grips into a tool holder (collet, Weldon, hydraulic, shrink-fit, or integral taper); a cutting flute section with helical grooves that form the cutting edges; and an end geometry that may be flat (square), spherical (ball nose), or have a small corner radius (bull nose). Modern end mills are mostly made from solid carbide for production work, with HSS and cobalt still common for manual milling, light-duty CNC, and budget tooling. End mills differ from drill bits in three important ways: they cut on the periphery as well as the end (so they can side-mill); their flutes are designed for chip evacuation in a sideways cut rather than down a vertical hole; and they are generally not designed for plunge drilling — only end mills with a centre-cutting design (true centre-cutting flutes that meet at the centreline) can plunge straight down without a pre-drilled pilot. We cover this distinction in the applications section below. End mill types by geometry End mills come in many geometries, each suited to specific operations. Type Geometry Best for Square (flat) end Flat-bottomed, 90° corners General-purpose milling, slotting, profiling, pocketing with sharp internal corners. The default workhorse. Ball nose Hemispherical end, full radius 3D contouring, mould and die work, finishing curved surfaces. Always leaves a small scallop — needs fine stepover for surface finish. Corner radius (bull nose) Flat end with small corner radius General-purpose where corner strength matters more than sharp internal corners. Reduces stress concentration at the corner — much longer tool life than square end on hard materials. Corner chamfer Flat end with 45° (or other) chamfer at corner Combined milling and edge-breaking — chamfer the part edge in the same operation as the profile cut. Roughing (corn-cob) Serrated cutting edges along the length Heavy stock removal — breaks chips into small pieces, evacuates them efficiently. Surface finish is rough; follow with a finishing pass. Tapered Conical body — narrows toward tip Mould and die work with draft angles, tapered slots, EDM electrode roughing. T-slot cutter Wide flat cutter on a narrow shank Cutting T-slots and undercuts — used to machine machine-tool-table T-slots, jig fixtures, dovetail relief. Dovetail Angled cutting edges (45°, 60° common) Cutting dovetail slots in fixtures, slides, and machine ways. Thread mill Thread-form cutting edges Milling internal or external threads — useful for large threads, blind holes, and material that work-hardens (where a tap would seize). Drill mill Square end + drill point Combination tool — drills a hole then mills the side. Used in single-tool jobs to reduce tool changes. Engraving / V-bit Conical V-shape with sharp tip Engraving, fine detail, sign work. Cuts with the side of the V — tip angle determines line width. AIMS stocks the most common types as dedicated collections — Square End Mills, Ball Nose End Mills, Corner Radius End Mills, and Corner Chamfer End Mills. For tapered, T-slot, dovetail, and thread mills, contact us — we can source most specialist geometries through our supplier network. Material substrate: HSS vs cobalt vs carbide The cutting tool material — the substrate — is the most fundamental choice. It determines how fast you can run the tool, how long it will last, and what work materials you can cut. Substrate Hardness / Heat resistance Best for Trade-off High-Speed Steel (HSS) ~63–66 HRC, to ~600°C Hand mills, manual machining, soft materials (aluminium, brass, plastic, mild steel at low speed). Forgiving — can be reground. Slowest cutting speed. Wears quickly on harder materials. Cobalt HSS (M35, M42) ~67–70 HRC, to ~700°C HSS-grade work but at higher speeds, or harder materials like stainless steel. Stronger and more heat-resistant than plain HSS. More expensive than HSS; still well below carbide in pure cutting speed. Solid carbide (tungsten carbide) ~89–93 HRA, to ~900°C+ Production CNC, all metals including hardened steel, stainless, titanium. The default for serious machining. Brittle — chips and shatters under shock or interrupted cuts; cannot be reground at home; more expensive than HSS. Cermet / ceramic To 1,200°C+ High-speed finishing of cast iron and hardened steel. Specialist applications. Even more brittle than carbide. Requires very rigid setup and high-speed spindles. CBN / PCD Hardest available Polycrystalline diamond (PCD) for non-ferrous and composites; cubic boron nitride (CBN) for hardened steel. Specialist tooling, premium price. Not for general use. The practical rule: Use carbide for any production CNC work and any material above mild steel. Use HSS or cobalt for manual milling, hobby CNC, deep slotting where carbide breakage is a risk, or budget situations. AIMS stocks both — Sutton and Bordo HSS / cobalt, plus Sutton VHM solid carbide and various premium imports. For the full HSS vs carbide upgrade decision — RPM thresholds, cost-per-cut analysis, when each substrate wins, and the cobalt HSS bridge-upgrade — see our Carbide vs HSS End Mill: When to Upgrade deep-dive. Solid carbide vs indexable / insertable end mills Carbide end mills come in two construction styles: Solid carbide — the entire cutter (shank and flutes) is one piece of tungsten carbide. Best for small-to-medium diameters (typically up to 20–25 mm) and where dimensional accuracy matters most. When the cutting edges wear out, the whole tool is replaced or regrind. Indexable / insertable — a steel body with replaceable carbide inserts clamped or screwed in. Best for larger diameters (typically 16 mm and up) and high-volume work. When inserts wear, you rotate to a fresh cutting edge or replace just the insert — the body is reusable across many insert sets. The cost-per-edge analysis: A 16 mm solid carbide end mill might cost $80 and have 4 cutting edges total before scrap. An insert-type tool body costs more upfront ($200+) but each insert provides 2–4 fresh corners, and a single insert refill at $30–50 gives you another full set of edges. Over a long production run, indexable wins on cost per cubic centimetre of material removed. For lower volumes or one-off work, solid carbide is cheaper and simpler. Indexable end mills also let you mix insert grades for different work — a tougher grade for roughing, a finer grade for finishing — without changing tool bodies. Practical Machinist threads on indexable selection consistently note this flexibility advantage. Flute count: what 2, 3, 4, 5, 6 and 7+ flutes do The number of flutes is one of the most-asked questions and one of the most misunderstood. There is no single best answer — flute count is a trade-off between chip evacuation, cutting-edge engagement, and rigidity. Flute count Best for Why 1 (single flute) Plastic, very soft aluminium, hobby CNC routers Maximum chip clearance — handles long stringy chips that would weld to a multi-flute cutter. 2 flute Aluminium, brass, slotting, plunging, hobby work Big flute valleys = excellent chip evacuation. Plunge-capable (centre-cutting). Lower productivity than 3-flute on aluminium. 3 flute Aluminium and other non-ferrous (the modern preferred choice) Best balance of chip room and feed rate on aluminium. Most premium aluminium-specific end mills are 3-flute. 4 flute Steel, stainless, cast iron — general workshop default Smoother cut, better surface finish, higher productivity than 2-flute on ferrous metals. Smaller chip valleys, so not for aluminium where chips clog. 5, 6, 7 flute High-speed finishing in steel and stainless, light radial engagement More cutting edges = higher feed per minute at the same chip load. Only works at low radial engagement (under ~20% of cutter diameter) where chip clearance isn't the bottleneck. 8+ flute Specialist finishing, hard milling Maximum number of edges in contact for ultra-fine finishes. Niche applications. The aluminium rule (forum-validated, Practical Machinist + r/Machinists consensus): use 2 or 3 flute on aluminium. Aluminium chips are large and gummy; the deeper flutes of a 2- or 3-flute cutter let chips evacuate cleanly. A 4-flute end mill in aluminium will pack the flutes with chips, causing the chip to weld back to the cutter and either burn the cutter or break it. The depth-of-cut rule (from r/Machinists): up to about 2–3× cutter diameter depth, a 4-flute is fine in steel. Beyond 3× diameter — proper deep slotting — step up to 5, 6, or 7 flutes only if radial engagement is light (high-feed/peeling style). At full radial engagement (slotting), more flutes hurt because the chips have nowhere to go. Odd flute count for chatter control: 3, 5, and 7-flute end mills break up the regular tooth-impact harmonic that causes resonant chatter. On long-reach work, thin-wall parts, or harmonics-prone setups, switching from a 4-flute to a 5-flute (or from a 6-flute to a 5- or 7-flute) often dramatically reduces chatter without changing anything else. Helix angle and variable helix The helix angle — the angle of the cutting flutes relative to the tool axis — controls the smoothness of cut, the axial forces on the spindle, and chatter behaviour. Low helix (15–30°) — strongest tooth, lowest axial pull, used for hard materials and roughing. Less smooth cutting, more vibration. Standard helix (30°) — workhorse general-purpose angle. Good balance. High helix (38–45°) — smooth shearing cut, excellent finish, lower cutting forces. The default for aluminium and finishing in steel. Pulls the tool axially up into the spindle — needs solid pull-in on the tool holder. Variable helix (mixed angles) — different helix angles on different flutes (e.g. 35°/37°/35°/37°). Breaks up tooth-pass harmonics for chatter resistance. Almost always paired with unequal flute spacing for the same reason. Standard on premium stainless and titanium end mills. Variable helix + unequal flute spacing is the modern stainless steel and titanium recipe — the irregular tooth strikes prevent the chatter resonance that work-hardens stainless and tears titanium. Sutton, Iscar, Sandvik and most premium brands offer this configuration. Coatings: TiN, TiCN, TiAlN, AlTiN, ZrN, DLC, diamond Coatings extend tool life by reducing friction, raising the temperature limit before the carbide softens, and acting as a chemical barrier between the cutting edge and the work material. The wrong coating, however, can be worse than no coating at all — particularly with aluminium. Coating Colour Max temp Best for Avoid for Uncoated (bright carbide) Silver/grey ~600°C Aluminium, copper, brass, plastic — non-ferrous where coating affinity is a problem Steel and stainless above light cuts TiN (Titanium Nitride) Gold ~600°C General-purpose for HSS in mild steel and cast iron. Cheap, gives modest life increase. Demanding applications TiCN (Titanium Carbo-Nitride) Blue-grey to violet ~400°C Cooler-running operations, abrasive materials, cast iron at moderate speed High-temperature work TiAlN (Titanium Aluminium Nitride) Violet-bronze to dark grey ~800°C Steel, stainless, cast iron, hardened materials. Forms a protective Al₂O₃ layer at high temp. Aluminium — coating contains Al and chips weld to the tool AlTiN (Aluminium Titanium Nitride) Dark grey/black ~900°C High-temp steel, stainless, hard materials. Higher Al than TiAlN — even more heat-resistant. Aluminium — strong galvanic affinity, severe chip welding ZrN (Zirconium Nitride) Light gold/silver ~600°C Aluminium, copper, brass — low affinity to non-ferrous. The traditional aluminium coating. Steel and stainless AlCrN (Aluminium Chromium Nitride) Blue-grey ~1,100°C Hardened steel, titanium, dry/MQL machining, very high-temperature work Soft non-ferrous DLC (Diamond-Like Carbon) Black, smooth ~400°C Aluminium (premium), copper, graphite, plastics, fibreglass — extremely low friction surface Hot work — DLC degrades above 400°C CVD Diamond Matte grey-black ~700°C Graphite, carbon-fibre composites, ceramics, MMC. Ultra-hard. Steel and any iron-bearing material — diamond reacts with iron at cutting temperatures and degrades rapidly Warning: Never use TiAlN or AlTiN coated end mills on aluminium. TiAlN and AlTiN coatings contain aluminium oxide. When cutting aluminium, the aluminium chips have strong chemical and mechanical affinity for the aluminium-bearing coating — chips weld to the cutting edge ("built-up edge"), the welded chip then breaks off taking carbide with it, and the cutter fails rapidly. Forum consensus across Practical Machinist and r/Machinists is unanimous on this point. For aluminium, use uncoated bright carbide, ZrN, or DLC. AIMS stocks aluminium-specific Sutton and premium imports — call us if you need a specific spec. Coating selection by work material Work material Recommended coating Why Aluminium and aluminium alloys Uncoated, ZrN, or DLC Avoid Al-bearing coatings (TiAlN, AlTiN). Polished/uncoated carbide cuts cleanly. ZrN reduces built-up edge. DLC for premium production. Mild and medium steel TiAlN or AlTiN Heat resistance prevents tool softening. Bronze-violet TiAlN is the production default. Stainless steel (304, 316, 17-4) TiAlN or AlTiN with variable helix and unequal flute spacing Stainless work-hardens under chatter. Variable geometry breaks the harmonic; coating handles the heat. Hardened steel (42–55 HRC) AlTiN or AlCrN High-temp coatings handle the heat of hard milling. Many AlCrN-coated end mills are rated to 65 HRC at speed. Cast iron TiAlN or TiCN Abrasive material — coating provides wear barrier. TiCN for grey iron at moderate speed; TiAlN for nodular iron at higher speed. Titanium and Ti alloys (Ti6Al4V) AlCrN or specialist Ti coatings; some prefer uncoated polished Ti has low thermal conductivity — heat stays in the cutter. Specialty coatings handle this; some shops still prefer well-polished uncoated carbide with flood coolant. Brass, copper, bronze Uncoated or ZrN Soft, low-melt materials. Uncoated cuts cleanly; ZrN for production runs. Plastics, polymers Uncoated single-flute or 2-flute, polished Coating not required. Sharp uncoated edges and good chip evacuation are what matter. Carbon fibre composite, graphite CVD diamond or DLC Extremely abrasive. Diamond coating gives 10–20× tool life vs uncoated. Wood, fibreglass DLC or uncoated polished DLC reduces resin adhesion in fibreglass. Length classifications: stub, regular, long, extra-long End mill flute length is classified by reach beyond the shank: Stub — flute length roughly equal to or less than diameter. Maximum rigidity, minimum vibration. Use whenever depth allows. Regular (standard) — flute length roughly 2–3× diameter. The default workshop choice. Long — flute length 3–4× diameter. Reach when the part requires it; rigidity drops dramatically. Extra-long / extended — 4× diameter or more. Specialist tools for deep pockets and reach into restricted areas. Treat with care. The rigidity rule: tool deflection scales with the cube of stick-out length. Doubling the reach increases deflection 8×. Always pick the shortest end mill that gets to the depth you need. If you must reach deep, drop down to a smaller-diameter long-reach tool with reduced cutting parameters, or use a specialist extended-shank cutter with reduced flute length (only the bottom is cutting; the rest is a smooth necked-down stub for clearance). Climb milling vs conventional milling The two milling directions describe how the cutter rotates relative to the feed direction. Climb milling (down milling) — the cutter rotates with the feed direction. Each tooth enters the work taking maximum chip thickness, then exits taking zero. Cutting force pushes down on the part. This is the modern CNC default. Conventional milling (up milling) — the cutter rotates against the feed direction. Each tooth enters taking zero chip thickness and ramps up to maximum at exit. Cutting force pushes the part up and away. The default on older manual mills with backlash in the feed screws. Aspect Climb milling Conventional milling Tool life Better — tooth enters into existing chip Worse — tooth rubs and work-hardens before cutting Surface finish Better Worse Chatter Lower Higher Required setup Anti-backlash leadscrew or zero-backlash CNC drives Tolerates backlash in feed Risk Can grab on a manual mill with backlash, pulling work into cutter Lower risk on manual mills Best for CNC machining, finishing passes, all serious production Manual mills with backlash, very thin parts where downward force would lift them The "thick to thin" principle (Practical Machinist thread on this is a classic): in climb milling each tooth's chip starts thick at entry and thins to zero at exit — this means most cutting energy is spent at the start of the tooth's arc when the cutting edge is sharp and unloaded; by the time the tooth is rubbing it's only sliding along an already-cut surface. Conventional milling reverses this — the tooth rubs first, then cuts. The rubbing portion work-hardens stainless steel and burns the cutting edge. Climb whenever your machine allows it. Speeds and feeds basics Speeds and feeds are the most important runtime variable for end mills. They are also where most beginner-level mistakes happen — too slow burns the cutter, too fast breaks it, wrong chip load polishes the edge instead of cutting. The two key numbers: Cutting speed (V_c, also SFM in imperial) — how fast the cutting edge passes through the material, in metres per minute (m/min) or surface feet per minute (sfm). Set by work material and tool material/coating combination. Chip load (f_z, feed per tooth) — how much material each cutting tooth removes per pass, in millimetres per tooth (mm/tooth) or thou per tooth. Set by tool diameter, material, and operation type. Convert to RPM and feed rate: RPM = (V_c × 1,000) ÷ (π × D) where V_c is in m/min and D is cutter diameter in mm Feed rate (mm/min) = RPM × number of flutes × chip load (mm/tooth) Worked example: 10 mm 4-flute carbide end mill cutting mild steel at V_c = 100 m/min and chip load 0.05 mm/tooth. RPM = (100 × 1,000) ÷ (3.14 × 10) = ~3,180 RPM Feed rate = 3,180 × 4 × 0.05 = 636 mm/min Chip thinning — when radial engagement is less than half the cutter diameter (any peeling/finishing pass), the actual chip thickness produced is less than the programmed feed per tooth. To keep the chip at the correct thickness for the cutting edge, you need to increase the programmed feed per tooth proportionally. Most CAM software handles this automatically; manual programmers should know about it because under-fed cutters at low radial engagement rub instead of cut, polishing the edge into failure. For full reference tables on cutting speeds for HSS, cobalt, and carbide across common materials, see our Cutting Speeds and Feeds Chart. For cutting fluid selection and lubrication, see our Cutting Fluids Guide. End mill applications: side milling, slotting, profiling, ramping, helical, plunging Operation Description Best end mill Side milling (peripheral) Cutting on the periphery — light radial engagement, full axial 4-flute (steel) or 3-flute (aluminium) at high feed; fewer flutes for full radial engagement Slotting Full-diameter engagement, full chip valley load 2-flute (Al) or 3-flute (Al), 3- or 4-flute (steel). Centre-cutting required. Profiling / contouring Following a 2D or 3D path Square (2D), corner radius (2D with strong corners), ball nose (3D) Pocketing Hollowing out an enclosed shape Square or corner radius, plus a smaller-diameter end mill for tight internal corners Ramping Diagonal entry — cutter enters at an angle rather than plunging Centre-cutting end mill at a shallow ramp angle (typically 1–5°) Helical interpolation Spiral entry path — cutter follows a helix down into the work Centre-cutting end mill. The modern preferred entry for pockets — kinder to the tool than plunging. Plunging Cutting straight down like a drill Centre-cutting end mill only. Slow feed. Better to drill a pilot hole if depth is significant. Trochoidal milling Small-diameter circular tool path with high feed 5- to 7-flute high-feed end mill at light radial engagement and large axial depth Centre-cutting clarification: Not every end mill can plunge straight down. Centre-cutting end mills have flutes that cross the cutter centreline; non-centre-cutting do not — they have a small uncut zone in the middle and will simply spin without cutting if plunged. Most modern 2-, 3-, and 4-flute end mills are centre-cutting. Check the catalogue spec or the manufacturer's drawing if it matters for your application. End mill failure modes — what they tell you End mills don't usually fail without warning. The way they fail tells you what to change. Failure mode Cause Fix Edge wear (uniform) Normal end-of-life Replace tool. Check tool life is matching expected. Chipping (small cutting-edge fragments lost) Vibration, interrupted cut, hard inclusions in material, brittle coating mismatch Reduce chip load, check rigidity, switch to tougher grade or coating. Variable helix for chatter. Built-up edge / chip welding Wrong coating for material (Al-bearing on aluminium), insufficient cutting fluid, too low cutting speed Switch to uncoated/ZrN/DLC for aluminium. Increase speed. Use cutting fluid. Thermal cracks (comb cracks across edge) Thermal shock — interrupted coolant, poor coolant flow on hot work Use flood coolant or air blast consistently; avoid interrupting coolant during cut. Catastrophic breakage Excessive deflection, entered work too aggressively, tool stick-out too long, hit hardened inclusion Shorter tool, reduce engagement, ramp/helical entry instead of plunge, check work-holding. Polished/glazed edge with no cutting Chip load too low (rubbing instead of cutting); especially common at low radial engagement without chip thinning compensation Increase chip load. Apply chip thinning compensation. Check spindle speed isn't too high. Deflection-driven taper Tool flexing under sideload; long-reach tools, undersize cutters in heavy cuts Shorter tool, reduce stepover, use stiffer holder (hydraulic or shrink-fit), spring passes for finish. Building a starter end mill set for an Australian workshop For a small-to-medium AU workshop running a CNC mill (or a manual mill with DRO), a sensible starter end mill set looks like this. Adjust quantities based on actual workload — these are practical core picks, not exhaustive. For steel and stainless work (4-flute, TiAlN coated, solid carbide): 6 mm — for small pockets, slot work, fine detail 10 mm — general-purpose workhorse 12 mm — heavier roughing and faster removal 16 mm or 20 mm — only if your machine and work justify it For aluminium work (3-flute, uncoated or ZrN, solid carbide, high-helix): 6 mm — small details 10 mm — general-purpose Al workhorse 12 mm — bulk removal in Al For 3D contouring and finishing (ball nose, 2- or 4-flute carbide, TiAlN for steel, uncoated for Al): 6 mm ball nose 12 mm ball nose Specials worth having: One 10 mm corner radius (R0.5 or R1) end mill — when corners need to be strong, not sharp One 8 mm or 10 mm chamfer end mill (45°) — for breaking sharp edges in the same operation as profile One small (3–4 mm) HSS end mill — for delicate jobs where carbide breakage risk is higher than tool-life cost Budget vs premium decision: For high-volume production, premium brands (Sutton, Iscar, Sandvik, Garant, OSG) repay their cost in tool life and predictable performance. For low-volume jobbing, hobby work, prototyping, and one-offs, mid-tier branded tools (Sutton, Bordo) at sensible prices are the sweet spot. Cheap unbranded carbide can work for very simple aluminium cuts but tool-life and dimensional accuracy are unreliable — fine for hobby, risky for paid work. Buying end mills in Australia: brands, where to buy, common mistakes Australian-made brands Sutton Tools — manufactured in Thomastown, Victoria. Strong VHM (solid carbide) range, comprehensive HSS / cobalt range, well-priced for what you get. Sutton's E-series and VHM TiAlN are workshop staples in AU. AIMS stocks Sutton across square, ball nose, corner radius, and corner chamfer. Bordo — Australian-distributed range, stronger on HSS and cobalt for hand-mill and light CNC use. Good value for non-production work. Premium imports — Sandvik Coromant (Sweden), Iscar (Israel), Mitsubishi (Japan), Walter (Germany), OSG (Japan), Garant (Germany). All available in AU through specialist tool distributors. AIMS can source most premium imports on request — call for pricing and availability. Common buying mistakes: Wrong shank tolerance — modern collets and hydraulic holders need h6 ground shanks. Generic "carbide end mill" listings sometimes ship h7 or worse, which won't run true in a precision holder. Wrong overall length for the work — buying long-reach when stub-reach would do means the tool will deflect. Cube-of-length deflection rule applies. Buying a coating mismatched to the material — TiAlN is the common shop spec; using it on aluminium will burn the tool fast. Centre-cutting confusion — assuming a non-centre-cutting end mill can plunge. Always check. Cheap unbranded carbide — quality varies wildly. May be fine for soft material; rarely fine for production stainless. Mixing imperial and metric without converting — feed and speed charts are often in SFM and IPT (imperial) while AU shops run mm/min. Convert before programming. For PPE while milling: safety glasses are mandatory (see our Safety Glasses Guide for AS/NZS 1337 selection), and hearing protection for prolonged spindle work (see our Hearing Protection Guide). Cutting fluid selection drives tool life as much as feed and speed — see our Cutting Fluids Guide for selection by material. End mills at AIMS Industrial AIMS stocks 50+ end mills across the workshop-essential geometries: Square End Mills — Sutton VHM TiAlN (E562, E604), Sutton HSS, Bordo HSS cobalt — metric and imperial Ball Nose End Mills — Sutton solid carbide TiAlN — metric, for 3D contouring Corner Radius End Mills — solid carbide, common radius sizes Corner Chamfer End Mills — combined milling and edge-break Full End Mills & Milling Cutters collection — browse the full range For specialty geometries (T-slot, dovetail, thread mill, drill mill, tapered, specialty Al-only, premium imports), call us on (02) 9773 0122 or use our contact page. We work with a network of premium tooling suppliers and can source most specs. Related AIMS Selectors This guide pairs with AIMS's other cutting-tool selectors. Use them together for complete coverage: Drill Bit Size Selector — every metric drill diameter linked to AIMS-stocked SKU. Drill Bit Selection Guide — choose drill bit type by material and application. Tap Drill Size Selector — every thread size linked to tap + matching drill SKU. Tap & Die Selection Guide — choose tap type by material, hole type, and machine. HSS vs Carbide End Mill — when to upgrade from HSS to solid carbide. Cutting Speeds & Feeds Reference — Vc and feed rate per material and tool diameter. Cutting Tool Materials — HSS, cobalt, carbide, PCBN, PCD compared. Cutting Tool Coatings — TiN, TiAlN, AlCrN, Helica, when each matters. Cutting Tool Troubleshooting — chipped edges, vibration, poor finish, snapped tools. Or browse the full end mills range, square end mills, ball nose end mills, corner radius end mills, and corner chamfer end mills — Sutton, Bordo and specialty brands in stock for next-day Australia-wide dispatch from our Milperra warehouse.Frequently Asked Questions What is the difference between a drill bit and an end mill? A drill bit only cuts on its tip and is designed to plunge straight down into the work, evacuating chips up the flutes. An end mill cuts on both its end and its sides — it is designed to be fed sideways past the work, removing material in a 3D path. Some end mills (centre-cutting types) can plunge like a drill in addition to side-milling, but most milling work is sideways feed. End mill flutes are designed for sideways chip evacuation rather than vertical hole evacuation. Is a 2-flute, 3-flute or 4-flute end mill better for aluminium? For aluminium use 2-flute or 3-flute. Aluminium chips are large and gummy, and the deeper flute valleys of 2- and 3-flute end mills evacuate them cleanly. A 4-flute end mill in aluminium will pack the flutes with chips, weld a chip back to the cutter, and either burn the cutting edge or break the tool. Modern preferred choice in production aluminium machining is 3-flute — best balance of chip room and feed rate. Why shouldn't I use a TiAlN or AlTiN coated end mill on aluminium? TiAlN and AlTiN coatings contain aluminium oxide. When cutting aluminium, the chips have strong chemical and mechanical affinity for the aluminium-bearing coating — chips weld to the cutting edge, creating a "built-up edge" that breaks off taking carbide with it. The cutter fails fast. For aluminium use uncoated polished carbide, ZrN coating, or DLC coating — none of which contain aluminium and so don't have the affinity problem. Forum consensus across Practical Machinist and r/Machinists is unanimous on this: stay away from TiAlN/AlTiN on aluminium. What is the best coating for end mills cutting stainless steel? TiAlN or AlTiN is the standard coating, paired with variable helix and unequal flute spacing geometry to break up the cutting harmonic that work-hardens stainless. The combination of high-temperature coating (handling the heat that doesn't transfer well to short curly stainless chips) and irregular flute timing (preventing chatter that work-hardens the cut surface) is the modern recipe for 304, 316, and 17-4 PH machining. Most premium end mill manufacturers offer this configuration as a "stainless steel" or "performance" line. What is the difference between HSS, cobalt and carbide end mills? HSS (high-speed steel) is the cheapest and most forgiving — it tolerates shock, can be reground, and is fine for hand mills, hobby CNC, and soft materials. Cobalt HSS (M35, M42) is HSS with cobalt added for better heat resistance — used for stainless steel and harder materials at HSS speeds. Solid carbide is the production standard — much harder, much more heat resistant, allows 3–10× higher cutting speeds — but it is brittle and shatters under shock or heavy interrupted cuts. For CNC production, carbide. For manual or hobby, HSS or cobalt. Can I use an end mill to drill straight down? Only if it is a centre-cutting end mill. Centre-cutting types have flutes that meet at the tool centreline and can plunge directly. Non-centre-cutting end mills have a small uncut zone in the middle — they will simply spin without cutting if plunged. Most modern 2-, 3- and 4-flute end mills are centre-cutting; many 5+ flute end mills are not. Check the catalogue spec. Even with a centre-cutting end mill, ramping or helical entry is kinder to the tool than vertical plunge, and produces a better finish. What does the helix angle of an end mill do? The helix angle is the angle of the flutes relative to the tool axis. Low helix (15–30°) gives the strongest tooth and lowest axial pull — used for hard materials and roughing. Standard helix (30°) is the general workhorse. High helix (38–45°) gives a smooth shearing cut with excellent surface finish and lower cutting forces — the default for aluminium and finishing in steel. Variable helix (e.g. 35°/37°/35°/37°) breaks up tooth-pass harmonics and is the standard for stainless steel and titanium where chatter is a problem. What is climb milling and is it better than conventional milling? Climb milling rotates the cutter with the feed direction — each tooth enters the work at maximum chip thickness and exits at zero. Conventional milling rotates against the feed direction. On modern CNC with anti-backlash drives, climb milling gives better tool life, better surface finish, and lower chatter — it is the modern default. On an older manual mill with backlash in the feed screws, climb milling can grab the work and pull it into the cutter; conventional milling is safer in that case. Once you have CNC drives or anti-backlash hardware, switch to climb. What is chip thinning and when does it matter? Chip thinning happens at light radial engagement (under about half the cutter diameter, common in peeling and finishing passes). The actual chip thickness produced is less than the programmed feed per tooth, because each tooth only contacts the work for a small arc. To maintain the correct chip thickness for the cutting edge to actually cut (rather than rub and polish), you need to increase the programmed feed per tooth proportionally. Most CAM software handles this automatically. Manual programmers should know that under-fed cutters at low radial engagement glaze instead of cut. What is the difference between a square end mill and a ball nose end mill? A square end mill has a flat bottom with sharp 90° corners — used for general milling, slotting, profiling, and any operation needing a flat-bottomed cut with sharp internal corners. A ball nose end mill has a hemispherical full-radius end — used for 3D contouring, mould and die work, and finishing curved surfaces. A ball nose always leaves a small scallop on a flat surface (the tool can't make a flat-bottomed cut), so you choose between them based on whether the work needs flat bottoms (square) or 3D curvature (ball nose). When should I use a roughing end mill? Use a roughing end mill (corn-cob serrations along the cutting edge) when you need to remove a lot of material fast and surface finish is going to be cleaned up by a finishing pass anyway. The serrations break the chip into small pieces, evacuate efficiently, and reduce cutting forces compared to a smooth-edged end mill at the same feed. Use a finishing end mill (smooth flutes, often higher flute count) for the final pass. The two-tool roughing-then-finishing strategy is standard for any non-trivial 3D job. How do I work out the right speed and feed for an end mill? Start from cutting speed (V_c) for the material/coating combination, in m/min. Convert to RPM: RPM = (V_c × 1,000) ÷ (π × D), where D is the cutter diameter in mm. Multiply RPM by the number of flutes and the chip load (mm/tooth) to get feed rate in mm/min. The hard part is picking V_c and chip load — these come from manufacturer charts or experience. See our Cutting Speeds and Feeds Chart for full reference tables across HSS, cobalt, and carbide on common materials. Why are odd-flute (3, 5, 7) end mills said to reduce chatter? Even-flute end mills have a regular tooth-strike pattern that can resonate with the natural frequency of the workpiece, the tool, or the spindle, producing chatter. Odd flute counts (3, 5, 7) — and especially variable helix with unequal flute spacing — break up that regular harmonic. The asymmetry means no single frequency dominates, and resonant chatter is much harder to set up. On long-reach work, thin-wall parts, or stainless and titanium, switching to an odd-flute end mill (or a variable-helix one) often dramatically reduces chatter without changing speed or feed. How long should an end mill last? Tool life depends entirely on material, speed, feed, depth of cut, coolant, machine rigidity, and how hard you push. Sensible production targets for a quality solid carbide end mill in steady ferrous machining are typically 60 to 240 minutes of cutting time. In aluminium, tool life can run into many hours per tool. In titanium or hardened steel, life can drop to 15–30 minutes. If you're seeing tool life under 30 minutes in mild or stainless steel, something is wrong — usually too high a chip load, wrong coating, insufficient coolant, or a rigidity problem. Track tool life on your work — it will tell you when something has changed. What are the most-used end mills in a general workshop? The 80/20 rule is real for end mills. In most general AU workshops, the bulk of work is done by: 4-flute solid carbide TiAlN-coated end mills in 6 mm, 10 mm, and 12 mm for steel and stainless; 3-flute solid carbide uncoated or ZrN-coated in 6 mm and 10 mm for aluminium; one 10–12 mm corner radius end mill for strong-corner work; one 6 mm and one 12 mm ball nose for any 3D contouring. A few HSS end mills in 4–8 mm round out the kit for delicate work where carbide breakage is a concern. AIMS keeps these popular sizes in stock — see our End Mills collection. If you need to drill into hardened or abrasive material, our carbide drill bits are the right tool for the job. AIMS Industrial stocks sutton tools — see the full range for trade and industrial use. Need ball nose end mills? Browse the AIMS range at ball nose end mills. What size end mills should a small AU workshop start with? A practical starter set for a small-to-medium workshop running a CNC or DRO-equipped manual mill is 6mm, 10mm and 12mm 4-flute TiAlN-coated solid carbide for steel and stainless, plus 6mm and 10mm 3-flute uncoated or ZrN-coated carbide for aluminium — adjust quantities based on actual workload rather than buying exhaustively. Should I buy premium or budget end mills for occasional jobbing work? For high-volume production, premium brands repay their cost in tool life and predictable performance. For low-volume jobbing, hobby work, prototyping and one-off jobs, mid-tier branded tools like Sutton or Bordo at sensible prices are the sweet spot — the tool life advantage of a premium brand matters less when a tool sits unused most of the time. What is a corner radius or chamfer end mill used for? A corner radius end mill (typically R0.5 or R1) leaves a rounded rather than sharp internal corner, which is stronger and less prone to stress cracking or chipping in service. A chamfer end mill (commonly 45°) breaks a sharp edge in the same setup as the profiling operation, avoiding a separate deburring step. Related AIMS Industrial Engineering References For deeper engineering data behind end mill selection — material identification, RPM and feed rates by material, coatings and tool material families — see the AIMS Phase 4 master references. Phase 4 master references (universal engineering data): Workpiece Material Cross-Reference Chart — SAE / AISI / DIN / JIS / AS/NZS equivalents across 20 material groups Cutting Speeds & Feeds Reference — RPM and feed rate by material and tool type — drilling, milling, tapping, reaming Cutting Tool Materials Guide — HSS, HSS-Co, PM-HSS, solid carbide, PCBN and PCD explained Cutting Tool Coatings Guide — TiN, TiCN, TiAlN, AlCrN and premium coatings with application matrix Cutting Tool Troubleshooting Guide — 33 symptoms diagnosed across drills, taps, endmills, reamers and bandsaw blades Metric to Imperial Conversion Chart — mm, inches, drill # and gauge cross-reference Sister selection guides in the AIMS application cluster: AIMS Drill Bit Selection Guide — HSS / cobalt / carbide / masonry / tile selection by material and application AIMS Tap & Die Selection Guide — Hand, spiral point, spiral flute and forming taps — metric and imperial For purchase advice, technical questions or items not currently listed, ring AIMS Industrial on (02) 9773 0122 or use the contact page. Trade accounts and bulk pricing available.
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Hacksaw Blade Guide: TPI, Materials & Selection
Hacksaw blades: how to choose TPI for any material, bi-metal vs all-hard vs flexible, cutting stainless steel and aluminium, correct blade direction, fitting, tension and technique.
Read moreHole Saw Guide: Sizes, Arbors & Pilot Drills
Hole Saw Selector — Choose by Trade This guide is a working selector tool — not just a reference. Most hole saw buying decisions come down to "what trade am I doing?" Pick your scenario below for a direct path to the right kit, or scroll down for the full bi-metal vs TCT vs diamond comparison and material-by-material RPM guidance. How to use: 1. Pick your trade / material 2. View the kit 3. Most kits include arbor + pilot drill — check the listing for what's included Electrician (Master Kit) Bi-metal HSS, 14pc 16-64mm Bordo 7010-S1 View → Steel (XP TCT) Tungsten carbide tip, 8pc 16-40mm Bordo 7080-S1 View → Thin Sheet Metal Thinwall design, 8pc kit Bordo 7040-S1 View → Tile / Glass (Diamond) Brilliant Diamond set Bordo 7084-S2 View → Tradesman All-Purpose 11pc 16-60mm general kit Bordo 7030-S1 View → Plumber (Pipe / Deep Cut) Ripper TCT, 16pc 16-114mm Bordo 7075-S3 View → Diamond Holesaw (Sutton) Sutton 8pc segmented set Sutton H1150011 View → Arbors + Pilot Drills Sutton H122 quick-release Sutton H122 View → Bordo XP is the workshop-standard hole saw range at AIMS — premium HSS bi-metal teeth, tungsten carbide tip (TCT) and diamond options. Sutton range covers single hole saws + arbors + pilot drills. P&N for budget kits. Need help? Call (02) 9773 0122. Jump to: Types RPM Sizes By Material Arbors Technique Failures Brands Related Selectors AIMS Top Picks — Pick the Right Hole Saw Fast AIMS stocks 130+ hole saws across bi-metal, TCT carbide, diamond and annular cutters. Sutton + Bordo dominate the AU professional range, with trade-specific sets for sparkies, plumbers, locksmiths and chippies. Recommendations below by material + job. Call (02) 9773 0122 for the right diameter + arbor. For Steel, Sheet Metal & General Workshop Job Type AIMS recommendation Why this one Workshop default (mild steel + sheet) Bi-Metal Cobalt M42 Sutton H125 Bi-Metal Cobalt The AU workshop standard. M42 cobalt teeth on flexible backing — for mild steel up to 5mm + sheet metal Sutton starter kit (5-piece) M42 set Sutton H125BM1 Bi-Metal M42 Starter 5pc 5-piece starter pack — common workshop sizes (19/22/29/35/44mm typical) with mandrel Plumber set (5 pieces) M42 plumber set Sutton H125BM7 M42 Plumber Set Sizes for common AU plumbing pipes — copper, PEX, PVC Heavy duty bi-metal range M42 14–152mm Sutton H105 Bi-Metal Heavy Duty 14–152mm Heavy-duty wall thickness for deeper cuts. Range 14–152mm covers most workshop needs Bordo value bi-metal HSS Cobalt Bi-Metal Bordo HSS Cobalt Bi-Metal Bordo's value-tier bi-metal — workshop volume at lower cost than Sutton premium Engineers set (Pferd 13-piece) Bi-Metal engineers Pferd Bi-Metal Engineers 13pc 13-piece engineering set — covers fab shop standard sizes with mandrel + ejector For Impact Drivers (Tough Materials, Cordless Drills) Job Type AIMS recommendation Why this one Impact-rated bi-metal HSS Impact Sutton H119 Impact Bi-Metal HSS Impact-rated teeth — for use on cordless impact drivers (where standard bi-metal teeth fracture) Impact arbor Impact-rated arbor Sutton H112 Impact Arbor Heavy-duty arbor rated for impact driver torque. Pairs with H119 for impact-driver work Quick release pilot drill (impact) Quick release Sutton H122 Quick Release Pilot Drill One-handed pilot drill change — speeds up trade work, especially in roof/wall cavities For Hardened Steel, Cast Iron & Heavy Duty (TCT Carbide) Job Type AIMS recommendation Why this one Carbide tipped workhorse TCT (Tungsten Carbide Tip) Sutton H128 Carbide Tipped TCT teeth for hardened steel + cast iron + stainless production. 5-10× life of bi-metal on tough material Bordo XP premium TCT TCT XP series Bordo XP TCT Tungsten Carbide Bordo XP — premium TCT range. AU trade favourite for steel beam + thick plate work Bordo XP2 deep cut XP2 deep cut TCT Bordo XP2 Deep Cut TCT Deep-cut variant — for thicker stock (up to 50mm deep). 2025/26 release Bordo Ripper TCT Ripper TCT Bordo Ripper TCT Ripper geometry — aggressive teeth for fast cutting at the expense of finish. Industrial production TCT starter kit (16-40mm) Bordo XP set Bordo XP 8-piece Set 16-40mm 8-piece starter — common steel-cutting sizes in a Bordo XP kit Sutton multi-purpose TCT Multi-purpose TCT Sutton H127 Multi-Purpose TCT Versatile TCT — handles steel, wood, plastic, plasterboard in one disc. For mixed trade work Trade-Specific Sets (Sparkies, Plumbers, Chippies) Trade Set AIMS recommendation Why this one Sparkies (electrical) Bordo 7010-S4 Bordo 7010-S4 Sparky's Kit 16-50mm 9-piece bi-metal set — sizes for common AU GPOs, downlights, conduit, junction boxes Sparkies (master TCT) Bordo 7010-S1 Bordo 7010-S1 Electrician's Master 14pc 14-piece master kit — bi-metal sizes covering full sparky range to 64mm Multi-purpose TCT sparkies Sutton H127MP9 Sutton H127MP9 Multi-Purpose Electrician 6pc TCT for sparkies cutting through mixed materials (plaster + steel stud) Plumbers (pipe + tank) Bordo 7010-S3 Bordo 7010-S3 Plumber's Pipe 16pc 16-114mm 16-piece kit — sizes for AU copper + PVC + PEX pipe and tank flange holes. 114mm max Plumbers TCT (Ripper) Bordo 7075-S3 Bordo 7075-S3 Ripper TCT Plumber's 16pc TCT version of plumber's kit — for cast iron + thick steel pipe Multi-purpose TCT plumbers Sutton H127MP7 Sutton H127MP7 Multi-Purpose Plumber 9pc TCT for plumbers cutting through mixed materials Chippies (carpenter) Sutton H127MP6 Sutton H127MP6 Multi-Purpose Carpenter 8pc TCT for chippies — wood + occasional steel + plaster. 8 common sizes Chippy's master kit (Bordo) Bordo 7010-S2 Bordo Chippy's Master Kit 15pc 15-piece master kit for chippies — covers 16-114mm range Locksmiths Bordo 7010-S5 Bordo 7010-S5 Locksmith's Kit 13pc 10-54mm Locksmith-specific sizes — for door lock + deadbolt installs Downlight installer Sutton H127MP4 Sutton H127MP4 Multi-Purpose Downlight 6pc Downlight-specific TCT sizes — through plaster + steel stud + insulation For Tile, Stone & Concrete (Diamond) Job Type AIMS recommendation Why this one Diamond segmented (concrete + masonry) Diamond segmented Sutton H115 Diamond Segmented 19-105mm Segmented rim for concrete, masonry, brick. 19-105mm range. Pair with H115 pilot drill Bordo diamond (premium tile + porcelain) Brilliant Diamond Bordo Brilliant Diamond Bordo premium diamond — for porcelain tile, marble, granite. Wet cutting recommended Saber diamond hole saw Diamond Saber Diamond Holesaw Saber diamond — value tier diamond for occasional tile work Diamond set (8-piece) Sutton diamond kit Sutton H1150011 Diamond 8pc Kit 8-piece diamond segmented kit — common tile sizes For Annular Cutters (Magnetic Drill Press) Job Type AIMS recommendation Why this one Mag drill annular cutter (HSS) HSS annular Sutton H180 Annular Cutter HSS Standard HSS annular cutter for magnetic base drill machines (mag drills) Mag drill annular cutter (TiAlN coated) HSS TiAlN annular Sutton H182 M2Al HSS TiAlN TiAlN-coated for steel beam + structural drilling on mag drill Euroboor annular cutter Weldon HSS Euroboor 30mm Weldon HSS Euroboor brand — workshop favourite for mag drill operators. Weldon shank standard Buying tip from AIMS: Match the hole saw teeth to the material. Bi-metal cobalt (M42) = workshop default for mild steel up to 5mm + sheet. TCT carbide = step up for hardened steel, cast iron, stainless production, or anything >5mm thick. Diamond = tile, concrete, masonry only (don't use on metal). For impact drivers, use impact-rated bi-metal (Sutton H119) — standard bi-metal teeth fracture under impact load. Always lubricate steel cutting with cutting fluid for 3-5× longer disc life — see the Tap Magic Cutting Fluids Guide.Hole Saw Types — Bi-Metal, TCT, Diamond, Masonry — Quick Reference Four core types cover the full range of materials a hole saw realistically cuts. Bi-metal HSS hole saws (the workshop default) Bi-metal hole saws have a body of low-carbon spring steel with high-speed steel (HSS) teeth electron-beam-welded to the cutting edge. Material Right hole saw Tool / cooling Wood, plasterboard Bi-metal HSS Standard rotary drill, dry Mild steel up to 6 mm Bi-metal HSS Cutting fluid, slow speed Stainless steel TCT Cutting fluid, very slow speed Cast iron, hardened steel TCT Cutting fluid, very slow speed Fibre cement (Hardiplank) TCT (multi-purpose) Standard drill, dust mask, dry Aluminium, brass, copper Bi-metal HSS Cutting fluid optional, moderate speed Tile, porcelain, glass Diamond grit Water cooling mandatory, slow speed Brick, concrete, blockwork Masonry tungsten carbide Hammer drill, dry What a Hole Saw Actually Is — Technical Definition A hole saw is a cylindrical drilling tool that cuts a circular hole by sawing the perimeter rather than removing all the material in the hole. The cup-shaped saw has cutting teeth around its open mouth and a centre pilot drill that locates the cut. As the tool spins, the teeth saw a circular kerf around the circumference; the material inside the kerf — the "core" or "slug" — comes out intact when the cut breaks through. The cut diameter equals the hole saw's outside diameter, less the kerf thickness (typically 1.5–2 mm). Compared to a twist drill bit cutting the same diameter: Far less material removed — only the kerf is cut, not the entire hole volume. A 75 mm hole saw removes about 5% of the material a 75 mm twist drill would. Lower power required — sawing a thin kerf needs a fraction of the torque that drilling the full diameter would. Larger diameters practical — 50–200 mm holes that would be impractical with twist drills are routine with hole saws. For the comparison across all drill bit types and applications, see our Drill Bit Types Guide. Limited depth — cut depth is limited to the cup's internal length (typically 38–50 mm). Deeper holes need step-cutting or annular cutters. Hole saws span four main types defined by the cutting tooth material — bi-metal HSS, tungsten carbide-tipped (TCT), diamond grit, and tungsten masonry. Each type has a defined material range, cutting speed envelope, and service life. Mismatching the hole saw type to the material is the most common cause of premature tooth wear and the second most common cause of "the hole saw didn't work" complaints (the first being wrong RPM, covered later). This guide is written for trade and industrial users — electricians, plumbers, fabricators, sheet-metal workers, and maintenance technicians cutting holes in metal, plastic, wood, and masonry as part of their daily work. The principles apply equally to DIY use; the brand and grade recommendations skew toward professional-grade tools that survive repeated use. Hole Saw Types — Bi-Metal, TCT, Diamond, Masonry Four core types cover the full range of materials a hole saw realistically cuts. Bi-metal HSS hole saws (the workshop default) Bi-metal hole saws have a body of low-carbon spring steel with high-speed steel (HSS) teeth electron-beam-welded to the cutting edge. Cobalt content (typically 8% in M42 grade HSS) increases hardness and heat resistance. Properties: Cuts: wood, plasterboard, plastic, mild steel up to ~6 mm, stainless steel (with reduced speed), aluminium, copper, brass Doesn't cut: hardened steel, cast iron above 200 HB, masonry, tile, glass, ceramic Service life: hundreds of holes in mild steel; thousands in plasterboard or wood Cost: mid-range — typical 60 mm bi-metal $30–60 trade price Bi-metal is the AU workshop default. The Sutton H125 series (cobalt bi-metal) stocked at AIMS is a representative professional-grade range covering 14–127 mm diameters. Tungsten carbide-tipped (TCT) hole saws TCT hole saws have hardened tungsten carbide cutting edges brazed onto the saw body. The carbide is significantly harder than HSS and survives in materials that would dull bi-metal teeth quickly. Properties: Cuts: stainless steel (any grade), hardened steel, cast iron, fibre cement (Hardiplank, Villaboard), abrasive composites, multi-purpose use across mixed materials Doesn't cut: wood at high speed (TCT teeth are brittle and chip on impact), masonry (different carbide grade and tip geometry needed) Service life: 3–5× bi-metal in stainless steel and abrasive materials Cost: 2–3× bi-metal price for the same diameter TCT is specified when bi-metal won't cut the material (stainless, hard steel, fibre cement) or when the application is high-volume production cutting where the longer life pays back the higher cost. Diamond grit hole saws Diamond hole saws have a steel body with industrial diamond grit bonded to the cutting edge — no individual teeth. The diamonds abrade the material rather than sawing it. Properties: Cuts: ceramic tile, porcelain, glass, stone, marble, fibreglass, ceramic-composite materials Doesn't cut: metal (diamonds graphitise on iron at cutting temperature), wood (cutting action is wrong) Critical requirement: water cooling. Diamond hole saws must be flooded with water during cutting to prevent diamond loss and substrate cracking. Dry cutting destroys the saw in minutes. Service life: 30–80 holes in tile depending on tile hardness Cost: mid-to-high; small diamond hole saws are inexpensive but wear fast Tungsten carbide masonry hole saws Distinct from TCT metal hole saws — masonry hole saws use a different tungsten carbide grade (toughness optimised over hardness) and a hammer-action cutting geometry. Properties: Cuts: brick, concrete, mortar, blockwork, cement render Doesn't cut: reinforcing steel within the masonry — hits rebar and stops; need a metal hole saw to clear it Drilling mode: hammer drill or rotary hammer required; standard rotary drill not enough Cost: mid-range; comparable to TCT Material Right hole saw Tool / cooling Wood, plasterboard Bi-metal HSS Standard rotary drill, dry Mild steel up to 6 mm Bi-metal HSS Cutting fluid, slow speed Stainless steel TCT Cutting fluid, very slow speed Cast iron, hardened steel TCT Cutting fluid, very slow speed Fibre cement (Hardiplank) TCT (multi-purpose) Standard drill, dust mask, dry Aluminium, brass, copper Bi-metal HSS Cutting fluid optional, moderate speed Tile, porcelain, glass Diamond grit Water cooling mandatory, slow speed Brick, concrete, blockwork Masonry tungsten carbide Hammer drill, dry Cutting Speed (RPM) — The Most-Missed Specification Hole saw RPM is the single biggest factor in cut quality, tooth life, and successful completion. Wrong RPM kills hole saws. Cuts come from each tooth taking a controlled bite of material — too fast and the teeth skate on heated chips; too slow and the teeth grind without cutting. The relationship between hole saw diameter and target RPM is inverse: larger diameter = slower RPM. Why RPM matters Hole saws are specified by surface cutting speed (SFM in imperial, m/min in metric) — the speed of the cutting edge measured at the tooth tip. Bi-metal hole saws cut mild steel at approximately 25 m/min surface speed. A 25 mm bi-metal cutting at 25 m/min calculates to 318 RPM; a 100 mm bi-metal at the same surface speed calculates to 80 RPM. Same surface speed, very different drill RPM. For the broader cutting speed reference covering drill bits, taps, and lathe operations across HSS, cobalt and carbide tools, see our Drill Speed Chart and Cutting Speeds Reference. Hole saw diameter Mild steel (bi-metal) Stainless steel (TCT) Wood (bi-metal) 20 mm ~400 RPM ~150 RPM ~1500 RPM 30 mm ~270 RPM ~100 RPM ~1000 RPM 50 mm ~160 RPM ~60 RPM ~600 RPM 75 mm ~110 RPM ~40 RPM ~400 RPM 100 mm ~80 RPM ~30 RPM ~300 RPM 150 mm ~50 RPM ~20 RPM ~200 RPM These are starting figures; refer to the specific hole saw manufacturer's data sheet for the cutting saw being used. The trend matters more than the exact numbers — most users run hole saws far too fast. The single most common hole saw mistake: running on full drill speed regardless of diameter. A cordless drill on full trigger spins 2,000+ RPM. A 75 mm hole saw at 2,000 RPM will glaze its teeth in 30 seconds — the saw is destroyed before it has cut through. Slow the drill to half-trigger or less; the cut should sound like sawing, not whining. Variable-speed drills with electronic speed control hold the lower RPM under load. Fixed-speed drills don't — for serious metal cutting, a low-RPM drill press or a drill with a 2-speed gearbox in low gear is the right tool. Common Hole Saw Sizes and What They're Used For Hole saws come in graduated diameters; certain sizes are far more common than others because they match standard fittings, fixtures, and openings. Diameter Common application 17–25 mm Conduit entries (20 mm conduit), cable glands, small electrical fittings 25–32 mm Cable glands (25 mm), Cat6 wall plates, small downlights 32–40 mm Larger conduit, electrical socket boxes, plumbing pipe entries 40–54 mm Door lock cylinder bores, pipe through-holes, small recessed lights 54–70 mm Door knob latches (54 mm bore + 25 mm latch), exhaust fan openings 70–80 mm Standard downlight openings (70 mm and 76 mm AU standard sizes) 80–92 mm Larger downlights, sub-floor vents, switchboard cable entries 92–100 mm Recessed light fittings, vent ducts, conduit entries 100–127 mm Large vents, range hood ducting (100 mm), spa pipe through-holes 127–200 mm Large duct work, industrial pipe through-holes, specialty applications The downlight standard Australian recessed downlight fittings standardise on a small set of cut-out sizes — predominantly 70 mm and 76 mm for residential downlights, with 90 mm and 92 mm common in commercial. Electricians fit-out new homes cutting hundreds of these holes; specifying the downlight before specifying the hole saw is faster than the reverse. Conduit-to-hole-saw sizing for electricians The hole-saw size for an AU electrical conduit is not simply the conduit diameter — gland nuts and conduit fittings need clearance. Common AU electrical conduit sizes and the matching hole-saw diameter: Conduit nominal size Conduit OD (mm) Hole-saw diameter 16 mm ~16 20 mm 20 mm ~20 25 mm 25 mm ~25 32 mm 32 mm ~32 40 mm 40 mm ~40 50 mm 50 mm ~50 60 mm The hole-saw size matches the gland-nut OD plus small clearance, not the conduit OD. Always confirm against the specific gland-nut manufacturer data sheet — a few millimetres difference between brands is common. Selecting a Hole Saw for Your Material The four-factor selection process: Identify the material exactly. "Steel" isn't enough. Mild steel, stainless 304, stainless 316, hardened tool steel, cast iron, and Galvalume all need different hole saws or speeds. "Wood" isn't enough either — softwood, hardwood, treated pine, MDF, and plywood respond differently. Identify the material thickness. Hole saw cup depth (typically 38–50 mm) limits the maximum cut depth. Thicker material requires multi-step cutting from both sides or a different tool (annular cutter, plasma). Match hole saw type to material. Use the table earlier: bi-metal for wood/mild steel, TCT for stainless and hard steel, diamond for tile/glass, masonry-grade for brick/concrete. Specify the diameter. Match the application — fitting standard, fixture standard, or mating part dimension. For mixed-material applications (multi-purpose TCT), pick the hardest material in the mix as the limiting factor. A TCT multi-purpose hole saw handles wood, fibre cement, and stainless in succession; a bi-metal would dull on the stainless cut. Hole Saw Arbors and Mandrels The hole saw itself doesn't fit a drill chuck — it threads onto an arbor (also called a mandrel) which holds the pilot drill and connects to the drill chuck. The arbor is often forgotten in first-time hole saw purchases. Arbor types and compatibility Universal arbor — fits a range of hole saw sizes via a threaded back. Sutton's H112UA2 universal arbor at AIMS fits hole saws 32–54 mm; smaller arbors handle 14–30 mm; larger arbors above 54 mm. Most users own two arbors covering the small and large size ranges. Quick-change / quick-fit arbor — proprietary connection allowing fast hole saw swapping without unthreading. Convenient for high-volume work; locks the user into one brand's hole saw range. Hex shank / SDS arbor — for use in impact drivers (hex) or rotary hammers (SDS). Less common; check drill compatibility first. Pilot drill The pilot drill in the arbor centre locates the hole saw cut and prevents the saw from "walking" across the surface before the teeth engage. Standard pilot drills are HSS twist drills 6–10 mm diameter. They wear out with heavy use; replacement pilot drills are available separately. Use a short pilot drill — screw-machine-length or stub-length, not a standard jobber-length. Long pilot drills wander off-centre as the saw begins cutting, especially in cordless drills with hand-held alignment. Short pilots stay rigid and on-mark. For production-volume work, drill-guide bushings (a hardened steel sleeve clamped to the workpiece, pilot drill running through the sleeve) eliminate wander entirely — the right setup for cutting hundreds of identical holes. For one-off and small-batch workshop cuts, clamping the workpiece in a bench vice is the standard approach. A vice provides solid, hands-free stability and eliminates the spinning-plate hazard that occurs when a hole saw catches in unsecured sheet or thin plate material. Cutting Technique — Pilot Drill, Pressure, Cooling A correctly-specified hole saw cuts cleanly when used correctly. Common technique steps: Step 1 — Mark the centre and pilot Mark the cut centre with a punch (centre punch on metal, awl on wood, marking pen on tile). Position the pilot drill on the mark. Confirm the hole saw is square to the surface. Step 2 — Start at low RPM Begin cutting at the slowest reasonable RPM — pilot drill engages, hole saw teeth start kerf. Once the kerf is established (visible groove), maintain that RPM through the cut. Don't speed up. Step 3 — Apply moderate, steady pressure Push hard enough that each tooth takes a chip. Too light = teeth skate, glazing the cut. Too heavy = teeth break or the drill stalls. The right pressure makes a steady cutting noise (sawing sound, not whine, not chatter). The single most damaging mistake — excessive feed pressure. Manufacturer data from Morse, Starrett and others consistently identifies excessive feed pressure as the number-one cause of damaged hole saws. Push hard enough that each tooth takes a chip; not so hard that the drill stalls or chatters. If the drill is bogging down or you are putting your weight behind it, you are over-feeding — broken teeth follow within seconds. Step 4 — Cool the cut on metal For mild steel, stainless, and aluminium, apply cutting fluid (CRC Tap-X, Trefolex, or equivalent) directly into the kerf. The fluid cools the teeth, lubricates the chip, and prevents tooth glazing. For diamond hole saws on tile, water cooling is mandatory — flooding the cut. Counter-intuitive on stainless: stainless steel needs FIRM feed pressure despite the slow RPM. Light pressure on stainless lets the hard chromium-bearing surface work-harden under the tooth tips, glazing both the workpiece and the saw. Push enough to keep each tooth biting fresh material; the cut should produce continuous chips, not glittery dust. Step 5 — Clear chips regularly Withdraw the saw every few millimetres of cut depth to clear chips from the kerf. Trapped chips cause heat build-up, glazing, and slug-jamming inside the cup. On metal, chip clearing every 30 seconds is reasonable. Step 6 — Slow down at break-through As the saw approaches the back surface, reduce pressure. Punching through at full pressure causes burr-out on the exit side and risk of breaking the pilot drill or rim teeth. Step 7 — Eject the slug The cut "slug" is held inside the saw cup. Eject through the saw's slot or with a punch through the rear hole; never with a hammer on the saw teeth. Common Failure Modes — and How to Avoid Them Glazed teeth (smooth, polished, won't cut) Cause: too high RPM, insufficient cutting pressure, no cutting fluid on metal. Once teeth glaze, the saw is finished — re-sharpening hole saws isn't economic. Fix: replace the saw; for the next cut, slow the RPM, increase pressure, and apply cutting fluid. Broken teeth (chunks missing from rim) Cause: too high cutting pressure, hitting embedded fastener or rebar mid-cut, dropping the saw. Fix: replace the saw; check the cut path for hidden fasteners or hardened inclusions; reduce pressure if drill is stalling. Slug stuck in the cup Cause: heat-welded, swarf-jammed, or normal interference fit on a clean cut. Three removal techniques in order of preference: (1) run the drill briefly in reverse — half a second of reverse rotation often breaks the slug free without any other intervention; (2) tap with a punch through the rear hole on the arbor — for hot-stuck slugs (welded), let cool first then tap; (3) for repeat sticking on the same job, install a slug-ejection spring inside the cup — pushes the slug out automatically as the saw withdraws. Walking / pilot drill skipping Cause: pilot drill blunt or worn; surface too smooth (polished steel, glazed tile); insufficient centre punch. Fix: replace pilot drill; punch a deeper centre dimple before cutting; use a bushing jig for production work. Smoke and burning at cut Cause: temperature too high — usually wrong RPM (too fast) or no cooling fluid. Fix: stop, let the saw cool, slow the RPM, apply cutting fluid before resuming. When NOT to Use a Hole Saw An honest specification guide should call out where hole saws are the wrong tool. Six situations where another method is correct: Material thicker than the cup depth (typically >50 mm). Hole saws can't cut deeper than their internal cup length. For deeper holes, use an annular cutter (purpose-built for thicker steel up to 100 mm) or step-cut from both sides. Production-volume metal cutting. Annular cutters are 3–5× faster than hole saws in steel and last longer. For high-volume hole drilling on the same machine, annular cutters with magnetic-base drill rigs are the right tool. Holes smaller than 14 mm. Small hole saws exist but twist drill bits are simpler, faster, and longer-lasting at small diameters. For graduated 4 mm to 35 mm holes in thin sheet metal, step drill bits are usually the right tool — see our Step Drill Bit Guide. Holes in living rebar-reinforced concrete. Diamond core drills with water cooling, or impact-rated SDS bits with hammer action, handle reinforced concrete. Masonry hole saws stop at the rebar. Cutting holes in safety glass, tempered glass, or laminated glass. These materials shatter or delaminate under hole saw pressure. Specify a glass-specific drill or have the holes cut by the glass supplier before tempering. Cutting through electrical cables, water pipes, or unknown services within walls/floors. Use a stud finder, wire detector, or cable scanner first. Hole saws cut blind into services with serious consequences — flooded floors, electrocution risk. Hole Saw Brands in Australia The AU hole saw market spans four broad tiers. Match the brand to the use intensity. Tier Brands Best for Premium engineered Starrett, Lenox, Milwaukee Hole Dozer, Bosch Pro High-volume professional work; specialist applications (extremely hard steel, exotic materials) Industrial / trade Sutton (AU brand), Irwin, DeWalt, Makita Daily trade and workshop use — electricians, plumbers, fabricators Mid-range / DIY Toolpro, Tactix, house brands Occasional DIY use, light renovations Consumer / supermarket Generic imports Single-use applications; one-off home jobs Sutton Tools is an Australian-manufactured cutting tool brand based in Melbourne — bi-metal cobalt hole saws (the H125 series) are stocked across the AU industrial supply chain and are the trade default for electricians, plumbers, and HVAC fitters. The Australian manufacture means consistent metallurgy, short supply chain, and AU-standard sizing. Premium brands (Starrett, Lenox, Milwaukee) earn their price in high-volume professional work — site-installation crews cutting hundreds of downlight openings per week, or fabricators in heavy stainless. For mid-volume trade work, Sutton or equivalent industrial-grade is the right balance. AIMS Industrial Hole Saw Range AIMS stocks hole saws and accessories across the Sutton bi-metal cobalt range plus arbors and pilot drill replacements. The full range — H125 series in 14–127 mm diameters, universal arbors, accessories — is in the Hole Saws & Accessories collection. For sourcing larger diameters, TCT or diamond grit hole saws not in stock, or arbors matched to specific drill chucks, contact the AIMS team. Companion guides: for the broader drill bit range and selection, see our Drill Bit Types Guide; for graduated sheet-metal holes in 4–35 mm sizes, see the Step Drill Bit Guide; for cutting speed and feed reference across drill bits, taps and lathe operations, see the Drill Speed Chart; for drill bit sizing in metric and imperial, see the Drill Bit Size Chart. Related AIMS Selectors This hole saw guide pairs with AIMS's other drilling and cutting selectors: Drill Bit Size Selector — for hole sizes below 16mm (where twist drills work best), every metric drill diameter linked to AIMS SKU. Drill Bit Selection Guide — broad guide on drill bit selection by material. Cobalt Drill Bit Guide — for stainless steel drilling, cobalt drills outperform bi-metal hole saws on smaller diameters. Tap Drill Size Selector — for threading work after drilling. Cutting Speeds & Feeds Reference — RPM by hole diameter and material. Cutting Tool Materials — HSS, bi-metal, TCT, diamond grades compared. Cutting Tool Troubleshooting — wandering, vibration, premature tooth wear. Or browse the full hole saws + accessories range — 130 products including Bordo XP kits, Sutton single hole saws, arbors, pilot drills and diamond holesaws. Next-day Australia-wide dispatch from our Milperra warehouse.Frequently Asked Questions What is a hole saw? A hole saw is a cylindrical drilling tool that cuts a circular hole by sawing the perimeter rather than removing all the material in the hole. The cup-shaped saw has cutting teeth around its open mouth and a centre pilot drill that locates the cut. As the tool spins, the teeth cut a circular kerf; the material inside the kerf — the core or slug — comes out intact when the cut breaks through. Hole saws cut diameters from 14 mm to 200+ mm in materials including wood, mild steel, stainless steel, aluminium, plastic, fibre cement, tile, glass, and masonry — using different cutting tooth materials (bi-metal HSS, tungsten carbide, diamond grit, masonry carbide) matched to the substrate. What's the difference between a bi-metal and a carbide hole saw? Bi-metal hole saws have HSS teeth on a spring-steel body — the workshop default for wood, plasterboard, mild steel up to 6 mm, aluminium, and brass. Tungsten carbide-tipped (TCT) hole saws have hardened carbide cutting edges brazed to the saw body — used for stainless steel, hardened steel, cast iron, fibre cement, and abrasive composites where bi-metal teeth dull quickly. TCT costs 2–3× bi-metal but lasts 3–5× longer in stainless and abrasive materials. Choose bi-metal for general workshop and trade use; specify TCT when bi-metal can't cut the material or when production volume justifies the longer life. What RPM should I run a hole saw at? Hole saw RPM is inversely proportional to diameter — bigger diameter, slower RPM. Bi-metal in mild steel: 20 mm = ~400 RPM, 50 mm = ~160 RPM, 100 mm = ~80 RPM, 150 mm = ~50 RPM. Stainless steel TCT: roughly half those RPMs (slower for harder material). Wood with bi-metal: roughly 4× the steel RPMs (faster for softer material). The single most common mistake is running a hole saw at full drill speed regardless of diameter — a 75 mm hole saw at 2000 RPM glazes its teeth in 30 seconds. Slow the drill; the cut should sound like sawing, not whining. What hole saw cuts stainless steel? Stainless steel needs tungsten carbide-tipped (TCT) hole saws — bi-metal HSS teeth dull on stainless within a few cuts. Use cutting fluid (CRC Tap-X, Trefolex, or equivalent) directly in the kerf for cooling and lubrication. Run very slow RPM — for a 50 mm hole in stainless, 50–60 RPM is the right range. Apply firm steady pressure (light pressure causes glazing on stainless). Withdraw to clear chips every few millimetres of cut depth. The same TCT hole saws that work on stainless also handle mild steel and aluminium — over-spec but no performance penalty. What hole saw cuts tile? Diamond grit hole saws cut ceramic tile, porcelain, glass, and stone. The diamond grit abrades the material rather than sawing it. Critical: diamond hole saws must be flooded with water during cutting — dry cutting destroys the saw within minutes by causing diamond loss and substrate cracking. Run slow RPM (typically 200–600 RPM depending on diameter and material). Use light pressure — let the diamond grit do the work. Tile cuts can be made dry with very small diameter saws and short cuts but professional tile work flood-cools every cut. How long does a hole saw last? Service life varies enormously by hole saw type, material being cut, and operator technique. Bi-metal hole saws in plasterboard or wood: thousands of cuts. Bi-metal in mild steel: 100–500 cuts depending on grade. Bi-metal in stainless: 5–20 cuts before glazing. TCT in stainless: 50–200 cuts. Diamond in tile: 30–80 cuts depending on tile hardness. Operator technique (correct RPM, cutting fluid, chip clearing) can double or triple these figures; running too fast or dry can cut them by 90%. Budget plan: bi-metal as service item replaced at noticeable performance drop; TCT and diamond as longer-lived but specialist tools. Can I cut concrete with a hole saw? Yes — with a tungsten carbide masonry hole saw and a hammer drill or rotary hammer. Standard rotary drills don't have enough impact action to cut masonry effectively; the drill must hammer as it rotates. Masonry hole saws are distinct from TCT metal hole saws — different carbide grade, different tip geometry. They cut brick, concrete, and blockwork but stop at reinforcing steel — hitting rebar requires a separate metal hole saw to clear. For deep holes through reinforced concrete, diamond core drills with water cooling are the professional answer. What size hole saw for a downlight? Australian recessed downlight fittings standardise on a small set of cut-out sizes — predominantly 70 mm and 76 mm for residential downlights, with 90 mm and 92 mm common in commercial fittings. Always confirm the cut-out size from the specific downlight manufacturer's data sheet before cutting — wrong size means the fitting either falls through or doesn't fit. Most electricians keep a Sutton or equivalent bi-metal hole saw in 70 mm, 76 mm, 90 mm, and 92 mm in their van for residential and commercial fit-outs. What is a pilot drill on a hole saw? The pilot drill is the small twist drill bit at the centre of the hole saw arbor. It locates the hole saw cut on the surface and prevents the saw from "walking" across the surface before the teeth engage. Standard pilot drills are HSS 6–10 mm diameter; they cut a small centre hole that the hole saw teeth then enlarge to full diameter. Pilot drills wear out with heavy use — replacement pilot drills fit standard arbors. Without a working pilot drill, the hole saw drifts off-centre at start; the resulting hole isn't where the centre punch was. What is a hole saw arbor? The arbor (also called a mandrel) is the connector between the drill chuck and the hole saw — the saw threads onto the arbor at one end, and the arbor's hex shank fits the drill chuck at the other end. The pilot drill mounts in the arbor centre. Universal arbors fit a range of hole saw sizes via standard threads; quick-change arbors use proprietary connections for fast swapping. Arbors are sized for hole saw diameter ranges — small (14–30 mm), medium (30–54 mm), and large (54+ mm) typical. Most workshops own two or three arbors covering the diameter ranges they use; buying a hole saw without checking arbor compatibility is a common first-time purchase mistake. Why does my hole saw smoke / burn? Smoke from a hole saw means temperature too high — usually wrong RPM (running too fast for the diameter) or no cooling fluid on metal cuts. Stop immediately, let the saw cool, slow the drill speed, and apply cutting fluid (CRC Tap-X or equivalent) before resuming. Continued cutting with a smoking saw glazes the teeth (smooth polished cutting edges that won't cut) — once glazed, the saw is finished. The cut should sound like steady sawing, not whining; smell the cut — burning smell means something is wrong. Why is my hole saw stuck — slug won't come out? The cut slug stuck in the saw cup is normal — interference fit on a clean cut, swarf-jammed on metal, or heat-welded on hot cuts. Eject through the rear hole on the arbor with a punch tap (tap, don't hammer hard, against the slug from behind). For hot-welded slugs, let cool fully first; trying to eject a hot slug warps the saw cup. For repeat sticking on the same job, install a slug-ejection spring inside the cup — pushes the slug out automatically as the saw withdraws. Can I sharpen a hole saw? Bi-metal hole saws can technically be sharpened on a tooth grinder, but it's rarely economic — the labour to sharpen a 60 mm bi-metal hole saw professionally costs more than a new one. TCT hole saws can be re-tipped at specialist tool sharpening services; only justified for premium-grade saws used in specialist applications. Diamond hole saws aren't sharpened — when the diamond grit is worn, the saw is replaced. For the vast majority of hole saw users, replacement at end-of-life is faster and cheaper than re-sharpening. What's the difference between a hole saw and an annular cutter? Both cut circular holes by sawing the perimeter. Hole saws use teeth all around the cup mouth; annular cutters have a different tooth geometry (chip-clearing slots and a precise rim) plus a coolant-fed centre. Annular cutters cut faster in steel (3–5× a hole saw), produce a cleaner edge, last 10–20× longer, and handle thicker material (up to 100 mm depth versus hole saw's 50 mm limit). Trade-offs: annular cutters need a stronger drill (typically a magnetic-base drill rig), cost more per cutter, and aren't suitable for wood. For high-volume metal cutting, annular cutters; for general workshop and trade use, hole saws. Where can I buy hole saws in Australia? AIMS Industrial stocks the Sutton (Australian-manufactured) bi-metal cobalt hole saw range across 14–127 mm diameters, plus universal arbors and accessories. The dedicated Hole Saws & Accessories collection covers the full Sutton range. For premium brands (Starrett, Lenox, Milwaukee) specialist tool retailers and Total Tools / Sydney Tools stock the range. For consumer DIY use, Bunnings and similar carry house-brand and Toolpro / Tactix grade saws. Match the brand tier to the use intensity — daily trade and workshop use justifies the Sutton industrial tier; one-off home jobs are fine on consumer-grade. Cross-reference our Pulley Speed Ratio guide for the V₂ = V₁ × (D₁ ÷ D₂) formula and worked examples. People Also Ask — Hole Saws Q: How do I cut a hole deeper than my hole saw's cutting depth? Standard hole saws have a limited cutting depth — typically 38mm to 51mm — which is not enough for thick timber, multiple laminated sheets, or deep sections. For deeper cuts, a step-cutting technique is used: make the initial cut to the hole saw's full depth, remove the plug (if it hasn't fallen free), flip the workpiece over and complete the cut from the other side using the pilot hole as a guide. For material that cannot be flipped, an arbor extension can sometimes be used to increase reach, though this reduces rigidity. Purpose-made deep-cut hole saws with taller cups are also available for timber applications where extra depth is regularly needed. Q: What arbor and pilot drill size do I need for a large hole saw? Hole saw arbors come in standard sizes matched to hole saw thread sizes — most hole saws up to approximately 152mm (6") use a standard arbor, while larger hole saws often require a heavy-duty arbor with a larger shank. The pilot drill (also called a mandrel drill) on most arbors is 6mm diameter, suitable for marking and guiding the hole saw through most materials. Larger arbors for big hole saws often use an 8mm or 10mm pilot. When selecting an arbor, check that the shank size matches your drill chuck (typically 3/8" or 1/2" chuck capacity) and that the arbor thread is compatible with your hole saws. Q: Should I use cutting fluid when cutting with a hole saw in metal? Yes — cutting fluid or oil is strongly recommended when using hole saws on mild steel, stainless steel, and other metals. The hole saw generates significant heat at the cutting teeth due to the large contact area, and without lubrication the teeth can overheat, lose their set, and blue or weld to the workpiece. Applying cutting oil to the tooth ring before and during cutting extends tooth life significantly. For thin sheet metal, a light oil or even a spray lubricant can be applied; for heavier plate, brush-on cutting fluid or paste compounds work well. Aluminium benefits from cutting fluid to prevent chips from welding to the teeth. Q: Why does the plug keep getting stuck inside my hole saw? Plug ejection from hole saws is a common frustration. Most hole saws have side slots that allow a screwdriver or rod to be inserted to lever the plug out — this is the intended removal method. To prevent sticking, avoid cutting all the way through the material with continuous pressure; instead, withdraw the hole saw periodically to clear chips. Some arbors include a spring-loaded plug ejector that pushes the slug out when the arbor button is pressed. For timber, the plug tends to jam more firmly than in metal due to wood fibre compression; working it loose by rocking the saw slightly before withdrawal reduces the problem. Q: What hole saw size should I use for electrical conduit? The correct hole saw size for electrical conduit depends on whether you are cutting for the conduit to pass through (clearance hole) or to mount a conduit fitting flush. Conduit is specified by nominal trade size, and the actual outside diameter differs from the nominal size. For example, 20mm nominal conduit typically has an OD of approximately 25mm, requiring a 32mm hole saw for a clearance pass-through. Conduit fittings specify the required knockout or hole diameter on their packaging. When in doubt, measure the conduit or fitting OD directly and add 2 to 3mm clearance — using a hole saw that is too small requires enlarging the hole; slightly too large is generally acceptable. Related AIMS Industrial Engineering References Pair this guide with the AIMS engineering reference cluster for material identification, cutting parameters and tool material selection. Phase 4 master references (universal engineering data): Workpiece Material Cross-Reference Chart — SAE / AISI / DIN / JIS / AS/NZS equivalents across 20 material groups Cutting Speeds & Feeds Reference — RPM and feed rate by material and tool type — drilling, milling, tapping, reaming Cutting Tool Materials Guide — HSS, HSS-Co, PM-HSS, solid carbide, PCBN and PCD explained Cutting Tool Coatings Guide — TiN, TiCN, TiAlN, AlCrN and premium coatings with application matrix Cutting Tool Troubleshooting Guide — 33 symptoms diagnosed across drills, taps, endmills, reamers and bandsaw blades Metric to Imperial Conversion Chart — mm, inches, drill # and gauge cross-reference Sister selection guides in the AIMS application cluster: AIMS Drill Bit Selection Guide — HSS / cobalt / carbide / masonry / tile selection by material and application AIMS Tap & Die Selection Guide — Hand, spiral point, spiral flute and forming taps — metric and imperial For purchase advice, technical questions or items not currently listed, ring AIMS Industrial on (02) 9773 0122 or use the contact page. Trade accounts and bulk pricing available. Need carbide drill bits? Browse the AIMS range at carbide drill bits. For sutton tools, see our sutton tools range stocked across Australia.
Read moreCutting Disc Guide: Types, Sizes & How to Choose for Steel, Stainless, Aluminium, Concrete & Wood
A cutting disc is the right tool for parting cuts — slicing through bar stock, angle iron, pipe, and sheet metal in a single pass. But reaching for the wrong type, the wrong thickness, or a disc that is past its service life can turn a routine job into a serious incident. This guide covers every decision: material selection, abrasive grain, thickness, tool compatibility, how to read the spec code, and the real relationship between price and quality. AIMS Industrial stocks cutting discs from PFERD and Klingspor — two of the most trusted names in bonded abrasives. See the full range at Discs & Wheels. What Is a Cutting Disc? A cutting disc is a thin, bonded abrasive wheel designed exclusively for parting cuts — separating material in a single straight pass at 90° to the workpiece surface. Cutting discs are typically 1–3mm thick. They rely on abrasive grains shearing through the material, not removing stock from a surface. Once the cut is made, the disc comes out — it is never dragged sideways. This is fundamentally different from the other two disc types used on angle grinders, and understanding the distinction is the single most important thing to know before picking a disc off the shelf: Disc type Thickness Working angle Purpose Cutting disc 1–3mm 90° (perpendicular to material) Parting cuts — slicing through material in a single pass Grinding disc 4–8mm 0–15° (nearly flat to surface) Stock removal, weld dressing, surface shaping Flap disc N/A (overlapping abrasive flap construction) 0–20° Surface blending, finishing, light removal Using a cutting disc as a grinding disc — applying lateral pressure to the face of the wheel — is the single most common cause of catastrophic cutting disc failure in the field. The thin construction is designed purely for axial load at 90°. It has no tolerance for side loading. For grinding and stock removal, see the AIMS Grinding Disc Guide. For surface blending and weld finishing, see the AIMS Flap Disc Guide. How a cutting disc is constructed Every bonded abrasive cutting disc is built from three elements pressed and cured under heat: Abrasive grain — the mineral that does the cutting (aluminium oxide, zirconia alumina, ceramic, or silicon carbide depending on the application) Phenolic resin bond — the matrix that holds grains in place while allowing them to fracture and release as they dull, continuously exposing fresh cutting edges Fibreglass reinforcement mesh — woven glass fibre layers (typically 2–4) that provide structural integrity and prevent the disc from disintegrating if it is loaded beyond its design limits The reinforcement layers are the primary safety feature. Quality cutting discs have at least two full layers of fibreglass mesh — you can see the grid pattern on both faces of the disc. Budget discs often have one layer or none at all, which is precisely why they disintegrate rather than wear down when they fail. This is not a performance issue; it is a structural safety issue. Cutting Disc Types by Material The material you are cutting dictates the disc you need. This is not just a performance consideration. Using the wrong disc on stainless steel will permanently compromise the metal's corrosion resistance. Using the wrong disc on aluminium will cause the disc to load and run hot within seconds. The selection table below covers the most common applications. Material to cut Disc specification Abrasive grain Critical requirement Mild steel, carbon steel General purpose metal cutting disc Aluminium oxide (A) or zirconia (Z) Standard metal disc — the widest range available; zirconia preferred for volume work Stainless steel INOX-rated stainless disc Zirconia (Z) — iron-free, sulphur-free, chlorine-free bond Must carry the INOX designation — confirmed on the disc, not just the packaging Aluminium Aluminium-specific cutting disc Aluminium oxide — open grain, soft bond formulation Non-loading bond is essential — standard discs clog almost immediately on aluminium Concrete, masonry, brick Masonry abrasive disc or diamond blade Silicon carbide (SiC) or diamond segment Abrasive SiC discs wear fast on hard concrete — diamond blades are more economical for volume work Tiles, ceramics Diamond cutting blade Diamond segments Abrasive discs will not cut tile cleanly or economically Mixed material / occasional use Multi-purpose metal disc Aluminium oxide or zirconia blend A legitimate compromise for occasional mixed-material cutting; not optimal for any single material Stainless steel — why a standard disc will cause rust Standard abrasive cutting discs contain iron and sulphur compounds in their bond matrix. When used on stainless steel, these contaminants embed in the cut surface under the heat and pressure of the cut. The result is surface rust, discolouration along the cut edge, and — in structural or food-grade applications — the risk of joint contamination that can cause corrosion failure over time. An INOX-rated disc is manufactured with an iron-free, sulphur-free, and chlorine-free bond. The term "INOX" comes from the French for stainless steel (acier inoxydable) and is the standard designation used by European abrasive manufacturers — PFERD, Klingspor, Tyrolit, and Flexovit all use it. In Australia, INOX discs are widely stocked and are the non-negotiable choice for any stainless work. Look for the INOX stamp on the disc itself. Do not rely on the box alone — packaging can be mixed in bulk storage. Aluminium — the loading problem Aluminium is soft and ductile. Under cutting conditions with a standard disc, aluminium particles heat, melt at the grain surface, and resolidify in the pores of the abrasive — a process called loading or glazing. A loaded disc stops cutting efficiently, the friction-generated heat increases rapidly, and the disc can seize in the kerf. Aluminium-specific cutting discs use a softer, more open bond formulation that releases loaded aluminium before the pores close. The grain releases before it glazes. The result is a clean, cooler cut with no risk of disc binding or thermal damage to the workpiece. For occasional thin-sheet cuts, some operators use a standard zirconia disc with a cutting fluid — this can reduce loading but is not a substitute for the correct disc in sustained aluminium work. Masonry and concrete Silicon carbide abrasive discs will cut masonry, concrete, and brick. They wear rapidly in these materials compared to metal cutting use, but they are adequate for occasional cuts — chasing a wall, cutting a block, trimming brick. For regular or production concrete cutting, a diamond blade is more economical despite the higher unit cost. Diamond blades are a fundamentally different product (industrial diamonds bonded in a metal segment matrix, not a consumable abrasive), and their selection — segment type, wet vs dry, continuous vs segmented rim — is outside the scope of this guide. Wood — a direct safety warning Standard abrasive cutting discs do not cut wood. The fibres shred and clog the abrasive grain within the first second of contact. TCT (tungsten carbide tipped) wood-cutting blades designed for angle grinders do exist — but they carry a significant kickback risk because the angle grinder's high RPM (10,000–12,000 RPM) combined with the circular blade's tooth geometry produces a grab-and-throw response when the blade catches. Under no circumstances should a standard wood circular saw blade be mounted on an angle grinder. A circular saw blade is rated for 4,500–5,500 RPM; an angle grinder runs at twice that speed or more, and the blade will disintegrate. Abrasive Mineral: What Determines Cut Quality The abrasive grain is the primary determinant of a cutting disc's performance and service life. Three grain types account for the vast majority of cutting discs sold for metal fabrication and industrial maintenance. Understanding what each does — and why — is the prerequisite for the price/quality question answered later in this guide. Aluminium oxide (marked A) Aluminium oxide is the standard entry-level abrasive mineral. It cuts by macro-fracture — as grains dull under load, they break off at random planes to expose fresh (but not necessarily sharp) cutting edges. The fracture event is unpredictable, and the resulting new edge is inconsistent in sharpness. Aluminium oxide performs adequately on mild steel in light-duty and occasional use. In sustained cutting of harder steels, stainless, or high-alloy material, the macro-fracture mechanism means the grain dulls quickly between fracture events, generating more heat and slowing the cut. Aluminium oxide is the dominant grain in budget and entry-level cutting discs. It is not a bad abrasive — it is simply the baseline. For cutting mild steel a few times a week, an aluminium oxide disc from a reputable brand with EN 12413 certification is a perfectly reasonable choice. The issue arises when budget manufacturers combine aluminium oxide grain with inadequate bond systems and insufficient fibreglass reinforcement — at that point the grain quality becomes irrelevant because the disc is structurally unsafe. Zirconia alumina (marked Z or ZA) Zirconia alumina is a blended mineral: typically 25–40% zirconia, balance aluminium oxide, combined at the grain level rather than as a simple mixture. Under cutting load, zirconia grains micro-fracture — breaking at the sub-grain level rather than at the full grain. Each micro-fracture event exposes a sharp, fresh cutting edge without releasing the grain entirely. The result is a disc that continuously self-sharpens under load, maintaining a sharper cutting edge for far longer than aluminium oxide. In practice: faster cut initiation, cooler running temperature, and substantially longer service life — typically 3–5 times more cuts per disc compared to equivalent aluminium oxide in the same application on steel. Zirconia is the correct choice for sustained metal cutting, stainless, and any application where disc life and cut quality are the primary concerns. It is available from all major manufacturers (PFERD, Klingspor, Flexovit, Norton) in standard sizes and at a price point that makes it the pragmatic recommendation for most Australian trade and industrial use. Ceramic alumina (marked CA or C) Ceramic alumina is the premium abrasive grain. The fracture mechanism is similar to zirconia but finer and more controlled — each micro-fracture event releases a smaller fragment and exposes a consistently sharper edge. Ceramic discs cut faster, run cooler, and last significantly longer than zirconia in the same application. They also generate less heat input into the workpiece — which matters when cutting stainless or heat-treated alloys where thermal damage at the cut edge affects mechanical properties. The performance premium is real. The cost premium is also real. For a maintenance workshop doing 10–30 cuts per week on mild steel and structural sections, the cost-per-cut difference between zirconia and ceramic narrows but rarely disappears. For a fabrication shop running grinders 4–8 hours daily, cutting stainless or high-alloy material, ceramic is the correct choice — the productivity and surface quality gains compound into measurable output over time. Silicon carbide (marked SiC or SC) Silicon carbide is harder and more brittle than aluminium oxide. It fractures readily — which makes it effective on hard, brittle materials like concrete, stone, and ceramics where impact-fracture cutting is appropriate. It is not suitable for metal cutting — it is too brittle to handle the ductile fracture mechanism of metal at the abrasive grain level and wears rapidly. Silicon carbide discs are the correct choice for masonry and light concrete cutting where diamond blades are not available or not warranted by the volume of work. How to Read a Cutting Disc Spec Code Every quality cutting disc carries a stamped specification. This is not decorative — it is the complete technical description of the disc and defines how it can safely be used. Being able to read the code takes 60 seconds to learn and is the most reliable way to confirm you have the right disc for the job. Dimensional specification: diameter × thickness × bore The first three numbers are always in the same format: outer diameter × thickness × bore diameter, all in millimetres. Examples: 125 × 1.0 × 22.23 — 125mm diameter, 1mm thick, 22.23mm bore (standard angle grinder arbour) 115 × 2.5 × 22.23 — 115mm diameter, 2.5mm thick, 22.23mm bore 230 × 2.0 × 22.23 — 230mm diameter, 2mm thick, 22.23mm bore (large angle grinder) 76 × 1.0 × 9.53 — 76mm diameter, 1mm thick, 9.53mm bore (die grinder) The 22.23mm bore is the international standard for angle grinder arbours. Die grinders most commonly use 9.53mm (3/8") or 6.35mm (1/4") bores. Never use a reducing or enlarging adaptor to fit a disc with a different bore diameter — the disc's rated RPM is specified for a given diameter at a given bore configuration, and adaptors change the dynamic load distribution in ways that can compromise that rating. Maximum RPM rating Every cutting disc is stamped with a maximum operating speed. This must not be exceeded. The tool's no-load RPM (listed in the tool's specifications) must be equal to or less than the disc's rated maximum RPM. Disc diameter Imperial equivalent Typical max rated RPM Surface speed (m/s) 115mm 4.5" 13,300 80 125mm 5" 12,250 80 150mm 6" 10,200 80 230mm 9" 6,650 80 76mm (die grinder) 3" 25,000–30,000 100 The surface speed at the disc rim is the underlying safety parameter — 80 m/s is the standard rated maximum for most bonded abrasive cutting discs. The RPM figure is derived from this at a given diameter. A larger disc at the same surface speed runs at a lower RPM; a smaller disc at the same surface speed runs at a higher RPM. This is why die grinder discs have maximum RPM ratings two to three times higher than angle grinder discs of the same surface speed rating. Abrasive type and grit code Following the dimensional spec is an alphanumeric abrasive identification code: A — Aluminium oxide (e.g., A46 = aluminium oxide, 46 grit) Z or ZA — Zirconia alumina CA or C — Ceramic alumina SiC or SC — Silicon carbide The grit number for cutting discs typically falls between 24 and 60. A lower grit number (coarser grain) cuts faster with a rougher kerf. A higher number cuts slower but cleaner. Most general-purpose metal cutting discs are 36–46 grit — an acceptable compromise between speed and kerf quality for structural and fabrication work. Date code and the 3-year shelf life rule This is the most commonly overlooked marking on a cutting disc — and potentially the most safety-critical. Abrasive cutting discs have a rated shelf life of three years from the date of manufacture. The phenolic resin bond degrades over time, even in unopened storage. Exposure to moisture, solvents, UV light, or temperature cycling accelerates degradation. A disc that has exceeded its shelf life can appear and feel completely intact but has reduced structural integrity under operating load — it fails without visible warning. The manufacture date appears as a quarter/year stamp on the disc face. Format: Q/YY — for example, 3/23 means manufactured in Q3 2023, with a rated use-by date of Q3 2026. Any disc without a visible date code should not be used. Any disc past its stamped date should be removed from service, regardless of how much of the abrasive face remains. Certification marks: EN 12413 and oSa Two independent marks tell you the disc has been manufactured and tested to a verified standard: EN 12413 — European standard for bonded abrasive products. Specifies dimensional tolerances, bond and grain quality requirements, burst-speed testing at 1.5× rated maximum, and marking requirements. EN 12413 is the standard referenced in Australian industrial safety procurement specifications and WorkSafe guidance on abrasive wheel use. oSa (Organisation for the Safety of Abrasives) — Independent third-party certification. The oSa mark indicates the manufacturer has undergone auditing of the manufacturing process, not just product batch testing. It is a higher bar than self-declared EN 12413 compliance. Budget and unbranded discs frequently carry neither mark. A disc without EN 12413 has not been burst-tested to a verified standard. In a procurement context, EN 12413 compliance is the minimum acceptable specification for any disc used in an Australian workplace governed by WHS legislation. Disc Thickness: 1mm, 1.6mm, 2mm, 3mm — When to Use Which Thicker does not mean stronger or safer for cutting discs. Thickness determines kerf width, material removal rate, and heat generation — not the disc's structural integrity under operating conditions. The common instinct to reach for a thicker disc for "harder" jobs is usually wrong. Thickness Best for Advantages Limitations 1.0mm Sheet metal, thin-wall tube, stainless steel, precision cuts requiring minimal heat input Fastest cut initiation, least heat generated, narrowest kerf (least material wasted), cleanest edge on thin material More susceptible to lateral deflection if disc wanders in the kerf on deep cuts through heavy sections 1.6mm General purpose metal cutting — the most versatile thickness in the Australian market Good balance of cut speed and resistance to lateral deflection. Widest disc selection available in AU. Handles the majority of fabrication and maintenance cutting tasks Slightly slower initiation than 1mm; slightly more heat 2.0–2.5mm Medium structural sections, bar stock, angle iron, heavy-wall tube More stable in the kerf on deeper cuts in heavy material; less likely to drift Wider kerf, more heat, slower cut than 1mm or 1.6mm on the same material 3.0mm Heavy structural steel, very deep cuts in thick material where the thinner disc has noticeably deflected Maximum stability in the kerf under load Slowest cut, most heat generated, widest kerf — only justified where thinner discs are visibly drifting Why thin discs are preferred for stainless steel Stainless steel work-hardens when exposed to heat. The longer a cutting disc is in contact with stainless, the more heat it drives into the cut zone, and the more the material hardens ahead of the disc — slowing the cut further and creating a feedback loop. A 1mm disc cuts faster and exits the material sooner, limiting total heat input. The result is a cleaner cut edge, less discolouration, and less risk of work-hardening that affects the mechanical properties of the joint. For stainless work: 1mm INOX zirconia disc, no pausing mid-cut, no dawdling in the kerf. The deflection concern Disc deflection — where the disc bends laterally in the kerf rather than tracking straight — is more common with 1mm discs on deep cuts in heavy material. The fix is technique, not a thicker disc: let the disc do the work (don't force it), keep the cut line straight, and clamp the workpiece so it cannot close on the disc. Forcing a thin disc sideways is how side-load failures happen, regardless of thickness. Size Guide: Matching Disc to Tool The disc diameter must match the tool's guard size — not just the spindle diameter. Running an oversized disc on a smaller grinder, even if it physically clears the guard, means the disc is operating at a surface speed above its rated maximum for that tool's RPM. The guard is not an arbitrary clearance specification; it is part of the RPM-to-surface-speed rating system. Angle grinder disc sizes — Australia Disc diameter Imperial equivalent Typical tool no-load RPM Standard bore Typical application 115mm 4.5" 11,000–13,300 22.23mm Light fabrication, confined spaces, one-hand operation, detail cutting 125mm 5" 10,000–12,250 22.23mm The most common size for Australian trade and industrial use. Handles the widest range of cutting tasks with the largest disc selection 150mm 6" 9,000–10,200 22.23mm Less common — sits between the two standard sizes. Used where a 125mm disc lacks the depth for a full cut in heavy material 230mm 9" 6,000–6,650 22.23mm Heavy structural fabrication, large-diameter pipe, construction cutting. Two-hand operation required The 22.23mm bore is the international standard for angle grinder arbours across all major brands — Makita, DeWalt, Bosch, Milwaukee, Metabo, and Hikoki all use the same arbour specification. Disc compatibility across brands is universal at the same diameter and bore, subject to the RPM rating matching the tool. Die grinder cutting discs Die grinders operate at 20,000–30,000 RPM — two to three times the speed of a 125mm angle grinder. They use small cutting discs: typically 50mm, 65mm, or 76mm in diameter, with bores of 9.53mm (3/8") or 6.35mm (1/4"). These discs are rated to 25,000–30,000 RPM at their small diameter to maintain the same surface speed. Angle grinder cutting discs must never be used on a die grinder, regardless of whether an adaptor makes them physically fit. A 125mm disc rated to 12,250 RPM, spun at 25,000 RPM on a die grinder, is operating at more than twice its burst-test rated speed. Failure is not a risk — it is a certainty. For small cutting discs suited to die grinders, see the AIMS range at Discs & Wheels. Rotary tools (Dremel and equivalents) Rotary tools use very small cutting discs — typically 38mm (1.5") diameter — rated to 30,000–35,000 RPM with a 3.2mm bore. These are a distinct product: thin, reinforced mini-discs for detail cutting in soft metals, plastics, fibreglass, and PCB material. They are not interchangeable with angle grinder or die grinder discs in either direction. The RPM adaptor trap Reducing adaptors (fitting a large-bore disc to a smaller arbour) and enlarging adaptors (fitting a small-bore disc to a larger arbour) are both potential RPM rating violations. A reducing adaptor does not change the tool's RPM — if the disc's rated RPM for that diameter is lower than the tool's no-load speed, the disc is being over-revved regardless of the adaptor. Check the disc's maximum RPM against the tool's specifications before using any adaptor. Does Price Equal Quality? The Honest Answer Yes — but not linearly, and the relationship matters most at the lower end of the price range where cost-cutting in manufacturing directly affects structural safety, not just disc life. Three tiers, three different conversations Budget / unbranded (under $1.50 per disc) At this price point, the primary concern is not performance — it is safety. Budget cutting discs are frequently manufactured with inadequate fibreglass reinforcement, without EN 12413 certification, and without verified burst-speed testing. Some carry no date code. The failure mode of a structurally inadequate disc is not gradual wear — it is sudden disintegration at operating RPM, with fragments ejected radially at the disc's rotational velocity. At 12,000 RPM, the rim of a 125mm cutting disc is moving at approximately 80 metres per second. A fragment from a disc that disintegrates at that speed has the energy of a high-velocity projectile. Across trade forums in Australia and internationally, there are first-hand accounts of disc fragmentation causing penetrating injuries — shrapnel embedded in forearms, cuts requiring ER attention, one member who lost partial sight in one eye. SafeWork SA, WorkSafe WA, and Safe Work Australia all publish specific guidance on abrasive wheel failure risk. This is not theoretical. Beyond the safety concern, cheap discs are also the most expensive option per cut. A budget aluminium oxide disc on mild steel may yield three to five cuts before it is spent. A mid-range zirconia disc from a reputable brand yields 25–40 cuts in the same material. The economics work against budget discs even before the safety calculation. Mid-range from reputable brands ($2.50–$6.00 per disc) Flexovit, Klingspor, DeWalt, Bosch, Metabo, and Norton at this price point carry EN 12413 certification, verified multi-layer fibreglass reinforcement, consistent grain distribution, and date-stamped shelf life. The performance difference over unbranded budget discs is substantial. The cost-per-cut calculation strongly favours mid-range zirconia: typically two to four times more cuts per dollar spent on mild steel, with the safety certification that budget discs lack. For most trade and maintenance environments in Australia, a mid-range zirconia disc from a reputable brand — confirmed EN 12413 certified — is the correct recommendation. It is safe, it performs well, and it is available at any trade supplier and Bunnings. AIMS stocks Klingspor and PFERD in this tier. Premium industrial ($6.00–$15.00+ per disc) PFERD, Walter, Tyrolit, and premium Norton lines use ceramic abrasive grain and proprietary bond formulations. The performance advantage over mid-range zirconia is real: faster cut initiation, cooler running, longer service life, and more consistent cut quality across the disc's life. The cost per cut in high-volume production use is often comparable to or marginally better than mid-range zirconia — the longer life offsets the higher unit cost. The honest assessment: for a maintenance workshop doing 20–50 cuts a week on structural steel, the premium over mid-range zirconia is difficult to justify on economics alone. For a fabrication shop running grinders four to eight hours daily cutting stainless, high-alloy steels, or hardened material, the ceramic performance advantage compounds into measurable productivity and surface quality gains that justify the cost. Cost per cut — the metric that actually matters Buying on unit price is the wrong frame. The calculation that matters is cost per cut: Disc type Approx unit cost Cuts per disc (mild steel, 125mm) Cost per cut Safety certification Budget / unbranded aluminium oxide $0.80–$1.20 3–5 $0.18–$0.40 Frequently none Mid-range zirconia (Klingspor, Flexovit) $3.00–$4.50 25–40 $0.08–$0.18 EN 12413 ✓ Premium ceramic (PFERD, Walter) $7.00–$12.00 60–90 $0.09–$0.17 EN 12413 + oSa ✓ The budget disc is simultaneously the most expensive option per cut and the most dangerous. The mid-range zirconia disc costs less per cut than the budget disc and comes with safety certification. The premium ceramic disc is comparable or marginally cheaper per cut than mid-range in production use and appropriate for demanding applications. What to look for when buying — regardless of price Before purchasing any cutting disc, confirm these five things: EN 12413 stamped on the disc itself — not just the packaging, which can be mixed in storage oSa logo — indicates third-party manufacturing process audit, not just batch product testing Visible fibreglass mesh weave on both faces — at least two layers, visible as a regular grid pattern in the body of the disc Date code present — quarter/year format (e.g., 2/24). If there is no date code, there is no way to verify the disc is within its three-year rated service life Abrasive type clearly marked — A (aluminium oxide), Z or ZA (zirconia), CA (ceramic), SiC (silicon carbide). If it is not marked, you do not know what you are buying Safety: The Three Failure Modes Cutting disc injuries follow predictable patterns. Every angle grinder-related disc injury in Australian WorkSafe incident reports falls into one of three categories. Understanding them is the most direct route to avoiding them. 1. RPM exceedance Every cutting disc has a maximum rated RPM derived from its burst-speed test. The tool's no-load speed must not exceed this figure. RPM exceedance occurs when: A disc is fitted via an adaptor that changes the effective diameter or bore — changing the dynamic load on the disc in ways the rating does not account for A die grinder disc is used in an angle grinder, or an angle grinder disc is used in a die grinder An old disc has been stored past its shelf life and the resin bond has degraded — the rated burst speed no longer applies to the degraded disc At excessive RPM, centrifugal tensile forces at the disc rim exceed the structural capacity of the bond and reinforcement. The disc does not crack — it disintegrates outward at full rotational velocity. There is no intermediate failure state. The disc is intact one moment and shrapnel the next. 2. Side loading A cutting disc is engineered for axial load only — force directed perpendicular to the disc face, into the material at 90°. Any lateral force applied to the disc face — pressing the cutting disc sideways into material, using it to grind a surface, or twisting the grinder in the kerf — generates bending stress the thin construction cannot tolerate. Side loading is the single most common cause of cutting disc failure in practice. The scenario is usually this: the operator wants to clean up the edge of a cut or remove a small amount of material, the cutting disc is already in hand, and they apply it to the surface at an angle. The disc fractures and ejects a fragment. If a grinding or flap disc is needed, change the disc. Do not use a cutting disc for any task that requires lateral contact. 3. Expired, damaged, or improperly stored disc Cutting discs degrade in storage. The three-year shelf life is a rated limit, not a conservative guideline. Accelerated degradation factors include: Moisture — resin bond absorbs water, weakening the matrix Solvent exposure — oils, cleaning fluids, and cutting fluids attack the phenolic resin Temperature cycling — repeated heat/cool cycles cause micro-stress in the bond Physical damage — dropping a disc more than 1 metre onto a hard surface can create internal cracks invisible to visual inspection Inspection before mounting: Check the date code — confirm within three-year rated life Visually inspect for chips, cracks, or delamination at the bore or disc edge Do not use any disc that has been dropped onto a hard surface from working height — internal cracking cannot be visually confirmed Do not use discs stored loosely in a toolbox without protection — rim chips from contact with other tools compromise the structural margin PPE requirements Minimum PPE for any cutting disc use on an angle grinder: Full face shield rated to AS/NZS 1337 — safety glasses alone do not provide adequate protection against disc fragmentation. A fragment from a 125mm disc moving at 80 m/s will pass through unrated eyewear. Wear both a face shield and safety glasses underneath if preferred. Hearing protection — cutting operations with an angle grinder routinely exceed 100–105 dB at the operator position. Sustained exposure without protection causes permanent noise-induced hearing loss. Cut-resistant gloves — rated for material handling and disc changes. Gloves do not mitigate disc fragmentation injury risk but reduce lacerations from handling cut material and sharp disc edges. Long sleeves and close-fitting clothing — abrasive sparks cause surface burns; disc fragments can cause penetrating injuries at exposed skin. The disc guard must always be fitted — running an angle grinder without the disc guard is a prosecutable WHS breach in all Australian jurisdictions. The guard is not optional for comfort or visibility. If the guard impedes the cut, reposition the workpiece. Browse the full range of angle grinder cutting discs, including PFERD and Klingspor, at AIMS Discs & Wheels. Frequently Asked Questions What is the difference between a cutting disc and a grinding disc? A cutting disc is thin (1–3mm) and used at 90° to make parting cuts — slicing through material in a single pass. A grinding disc is thick (4–8mm) and used at 0–15° for stock removal, weld dressing, and surface shaping. The two are not interchangeable. Using a cutting disc for grinding — applying lateral pressure to the disc face — is the most common cause of cutting disc failure in practice. For grinding disc selection, see the AIMS Grinding Disc Guide. Can I use a cutting disc to grind metal? No. A cutting disc is not structurally rated for lateral load. Pressing the face of a cutting disc against a surface generates bending stress the thin bonded construction cannot tolerate. It will fracture without warning. If you need to remove stock, dress a weld, or smooth a surface, fit a grinding disc or flap disc — both designed specifically for that load orientation. What cutting disc do I use for stainless steel? A disc marked INOX — confirmed iron-free, sulphur-free, and chlorine-free. Standard cutting discs contain iron and sulphur compounds in their bond that contaminate the stainless surface under the heat and pressure of the cut, causing rust and potential joint failure. INOX-rated zirconia alumina discs are the correct choice. Use a 1mm thickness to minimise heat input and reduce work-hardening at the cut edge. What cutting disc do I use for aluminium? A disc specifically designed for aluminium — labelled "AL" or "Aluminium" on the packaging. These discs use a soft, open bond formulation that releases aluminium before it loads (glazes) the abrasive grain surface. Standard steel cutting discs clog almost immediately on aluminium, generating significant heat and risking the disc seizing in the kerf. Do not use a general-purpose metal disc on aluminium for any sustained cutting work. What do the numbers on a cutting disc mean? The primary spec is diameter × thickness × bore in millimetres (e.g., 125 × 1.0 × 22.23). Following that: the abrasive type code (A = aluminium oxide, Z = zirconia, CA = ceramic, SiC = silicon carbide) and grit number. The maximum RPM is stamped separately. The date code in Q/YY format (e.g., 3/23 = Q3 2023) sets the three-year use-by date. EN 12413 and oSa marks confirm independent safety certification. What is an INOX cutting disc? INOX is the designation for a disc with an iron-free, sulphur-free, and chlorine-free bond — the specification required for cutting stainless steel without contaminating the surface. The term comes from the French for stainless steel (acier inoxydable) and is used as a standard designation by European abrasive manufacturers. In Australia, INOX-rated discs from PFERD, Klingspor, and Flexovit are widely stocked. Look for the INOX stamp on the disc face, not just the box. Why do cheap cutting discs shatter? Budget cutting discs are frequently manufactured with inadequate fibreglass reinforcement and without EN 12413 burst-speed certification. The fibreglass mesh is the primary structural safety feature of a bonded abrasive disc — it is what holds a stressed or overloaded disc together long enough to be detected rather than disintegrating instantly. Without it, a disc under operating load fails catastrophically rather than wearing down progressively. At 12,000 RPM, the rim of a 125mm disc is moving at 80 metres per second. Fragments from that disintegration have the energy of high-velocity projectiles. This is the documented mechanism behind angle grinder disc injuries in Australian WorkSafe incident reports. How long does a cutting disc last before it expires? Abrasive cutting discs have a rated shelf life of three years from the manufacture date, regardless of whether they have been used. The phenolic resin bond degrades over time — exposure to moisture, solvents, or temperature cycling accelerates this. A disc past its rated shelf life can appear intact but has reduced structural capacity under load. The manufacture date appears as a quarter/year code stamped on the disc face (e.g., 3/23 = Q3 2023, use by Q3 2026). Do not use any disc without a visible date code, and do not use any disc more than three years past its stamped manufacture date. Can I use an angle grinder cutting disc on a die grinder? No. Die grinders operate at 20,000–30,000 RPM. A standard 125mm angle grinder cutting disc is rated to approximately 12,250 RPM maximum. Fitting it to a die grinder immediately exceeds this rating by a factor of two or more. Die grinders require cutting discs specifically designed for their speed and bore size — typically 50mm, 65mm, or 76mm diameter, rated to 25,000–30,000 RPM with a 9.53mm or 6.35mm bore. Is a thinner or thicker cutting disc better? Thinner is better for most cutting applications: faster cut, less heat, narrower kerf, less material wasted. A 1mm disc outperforms a 3mm disc on sheet metal, tube, and stainless steel. The main reason to choose a thicker disc is to reduce lateral deflection when cutting very deep sections in heavy structural steel where the disc is visibly drifting in the kerf. For general trade and maintenance work, 1mm or 1.6mm is the correct starting point. What size cutting disc do I need for a 125mm angle grinder? A 125mm cutting disc with a 22.23mm bore. This is the most common disc and grinder combination in Australian trade and industrial use. Confirm the disc's maximum rated RPM meets or exceeds your grinder's no-load speed — for a 125mm grinder this is typically 10,000–12,250 RPM. Do not fit a 115mm disc on a 125mm grinder via an adaptor — the guard configuration changes and the rated RPM relationship is altered. What PPE do I need when using a cutting disc? Minimum: a full face shield rated to AS/NZS 1337 (safety glasses alone are not adequate protection against disc fragmentation), hearing protection (angle grinder cutting exceeds 100 dB at the operator position), cut-resistant gloves for disc handling and material positioning, and long sleeves. The disc guard must always be fitted — operating an angle grinder without a guard is a prosecutable WHS breach in all Australian jurisdictions. If the guard obstructs the cut, reposition the workpiece. For a complete overview of angle grinder types, sizes, speed ratings, and safe operating technique — including kickback prevention and PPE requirements for cutting disc work — see the AIMS Angle Grinder Guide. For cutting thicker sections where a cutting disc is impractical, or where complex contour cuts on mild steel, stainless, or aluminium are needed, see the AIMS plasma cutter guide. For cuts where sparks are a hazard, access is restricted, or a disc is impractical — such as cutting pipe in a tight space — a hacksaw offers a controlled, spark-free alternative. See the AIMS Hacksaw Blade Guide for blade selection by TPI, tooth form, and material. Our Pulley Speed Ratio guide covers the speed-vs-diameter relationship for V-belt and timing-belt drives. Related AIMS Industrial Engineering References For the engineering background to cutting disc selection — material identification, surface speed by material, and disc wear troubleshooting — see the AIMS Phase 4 master references. Phase 4 master references (universal engineering data): Workpiece Material Cross-Reference Chart — SAE / AISI / DIN / JIS / AS/NZS equivalents across 20 material groups Cutting Speeds & Feeds Reference — RPM and feed rate by material and tool type — drilling, milling, tapping, reaming Cutting Tool Materials Guide — HSS, HSS-Co, PM-HSS, solid carbide, PCBN and PCD explained Cutting Tool Coatings Guide — TiN, TiCN, TiAlN, AlCrN and premium coatings with application matrix Cutting Tool Troubleshooting Guide — 33 symptoms diagnosed across drills, taps, endmills, reamers and bandsaw blades Metric to Imperial Conversion Chart — mm, inches, drill # and gauge cross-reference Sister selection guides in the AIMS application cluster: AIMS Drill Bit Selection Guide — HSS / cobalt / carbide / masonry / tile selection by material and application AIMS Tap & Die Selection Guide — Hand, spiral point, spiral flute and forming taps — metric and imperial For purchase advice, technical questions or items not currently listed, ring AIMS Industrial on (02) 9773 0122 or use the contact page. 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