What Is Threaded Rod?
Threaded rod is a length of metal bar stock threaded continuously along its full length, from one end to the other. Unlike a bolt, which has a formed head and a specific shank length, threaded rod has no head — it's just thread, all the way through. That makes it endlessly adjustable: you can cut it to any length, run nuts and fittings anywhere along it, and use it for applications a standard bolt simply can't reach.
In the trade, threaded rod gets called a lot of different things. If someone asks you for allthread, stud rod, studding, Booker rod, hanger rod, or threaded bar — they're all talking about the same product. The terminology varies by industry, region, and how long the person has been in the game. We'll cover all the names below.
AIMS Industrial supplies threaded rod in a full range of grades, materials, and metric sizes — from M6 through to M36 in stock, with larger sizes and cut lengths available to order. If you need a specific grade or finish that isn't showing online, get in touch.
All the Names for Threaded Rod
This is one of those products that has accumulated more names than almost anything else in the fastener world. Here's the full list, and when you'll hear each one:
Threaded Rod
The universal standard term. Used by engineers, designers, and fastener suppliers worldwide. If you're specifying on a drawing or purchase order, this is what to write.
All Thread / Allthread / ATR
Short for all-thread rod — meaning threaded from end to end, as opposed to a stud bolt that has a plain shank in the middle. ATR is the written abbreviation you'll see on supplier datasheets. "Allthread" is common in the electrical, plumbing, and HVAC trades across Australia.
Threaded Bar
Common in the construction and civil trades, particularly for concrete anchor applications. "Threaded bar" often implies a longer length — 1 m or 2 m stock — rather than a short fastener.
Studding
The UK trade term, and still used in Australia by plumbers, electricians, and building services contractors. "A length of studding" means a section of fully threaded rod cut to suit the job.
Stud Rod
Common in the mechanical, electrical, and plumbing (MEP) sector. Often used alongside strut channel systems (Unistrut, OzStrut, EzyStrut) for suspending pipework, cable tray, and HVAC ducting from structural steel or concrete soffits.
Hanger Rod
The HVAC and fire protection term. When contractors hang duct, air handling units, or sprinkler pipework from a slab, they do it with hanger rods — typically M10 or M12 galvanised, fixed with a concrete anchor above and a clevis hanger or rod hanger bracket below.
Anchor Rod
The civil and structural term. Anchor rod is threaded bar chemically set (epoxied) into core-drilled holes in concrete — used for base plates, handrails, structural connections, and post-installed anchors. Typically specified as Grade 8.8 or stainless, not Grade 4.6.
Booker Rod (Australian Trade Term)
If you're in the Australian building and construction trade, you'll hear "Booker rod" used interchangeably with threaded rod or allthread. It's a fully genericised trade term — like "Biro" for a ballpoint pen or "Crescent spanner" for an adjustable wrench — where a brand name has become the common name for the product category. The name is most likely derived from Booker Bros, a major Australian building materials distributor that was widespread in the mid-20th century. You'll also see it spelled "Brooker rod" — that's the same thing, different spelling. Both circulate in the trade. If a sparky or plumber asks for Booker rod, hand them M12 HDG allthread and you'll be right.
Ready Rod / Redi-Rod
North American trade terms that occasionally appear in Australian catalogues and online searches. Same product — fully threaded rod, typically zinc-plated or HDG, sold in 1 m or 3 m lengths.
Coil Rod / Coil Thread Rod
A specific variant with a different thread profile — round crests rather than the standard V-form. Coil rod is used in formwork tie systems, rebar tying, and some proprietary concrete accessories. It is not interchangeable with standard metric threaded rod.
What Is Threaded Rod Used For?
Threaded rod is one of those products that appears on virtually every commercial building site and in most industrial maintenance workshops. The common thread across all applications is the same: you need something suspended, anchored, braced, or clamped at a precise position, using a fastener you can adjust and cut to length. Here's how each trade uses it.
HVAC
Suspending rectangular and circular ductwork from concrete soffits or structural steel. Fan coil units, air handling units (AHUs), and duct runs are hung on M10 or M12 HDG rod, passed through a concrete anchor above and terminated with a nut and vibration isolator below. For heavier AHUs and mechanical plant, M16 high-tensile rod is standard.
Plumbing
Pipe hangers for copper, stainless, PVC, and press-fit pipework. Threaded rod sets the drop from structural steel or slab to the pipe hanger bracket, allowing fine height adjustment with two nuts. M10 is the workhorse size for commercial plumbing hangers; M8 suits light-duty residential.
Electrical
Cable tray support, conduit runs, and switchboard base frames. Electrical contractors buy large quantities of M10 zinc-plated or HDG rod for supporting cable management systems throughout commercial fitouts and industrial switchrooms.
Fire Protection
Sprinkler pipe hangers to AS 1530. Fire contractors use HDG or stainless rod for sprinkler hangers and brace rods, with strict requirements on spacing, rod diameter, and anchor type. M12 HDG is typical for standard commercial sprinkler installations.
Construction and Civil
Post-installed anchor bolts: M16 or M20 Grade 8.8 rod is chemically set into core-drilled holes in concrete using two-component epoxy (Loctite 5088, Ramset HIT-RE 500 V4, or similar) for base plates, guardrail posts, mezzanine columns, and structural connections. Concrete formwork uses proprietary coil rod (not standard allthread) to tie form faces.
Workshop and Industrial Maintenance
Machinery bases and levelling feet, press frames, jig and fixture construction, custom clamps, structural shelf uprights, and industrial workbench legs. M12 is the most common size for workshop use — strong enough for most loads, easy to cut with a hacksaw, and compatible with standard hex nuts and coupling nuts.
DIY and Furniture
Industrial-style furniture — bookcase uprights, table legs, shelving systems — using M10 or M12 rod with washers and hex nuts as exposed fasteners. It's a popular look in commercial fitouts and home workshops, and threaded rod is cheap, strong, and adjustable.
CNC and Hobby Machining (Acme Thread)
When people search for threaded rod for CNC leadscrews, lathe repairs, or workbench vise screws, they typically need acme thread rod — not standard V-thread allthread. See the Acme Thread section below.
Grades and Strength Classes
Not all threaded rod is the same strength. Getting the grade wrong on a structural anchor or load-bearing hanger rod is a genuine safety issue — so this matters.
Grade 4.6 — Mild Steel (General Purpose)
The workhorse grade. Grade 4.6 has a minimum tensile strength of 400 MPa and a yield strength of 240 MPa. It's suitable for general construction, MEP suspension, light structural work, and most non-safety-critical applications. When someone says "standard allthread" in Australia, they usually mean Grade 4.6 galvanised.
Manufactured to DIN 976 / AS 2451. Available in zinc-plated, hot-dip galvanised (HDG), and plain (bare steel) finishes.
Grade 8.8 — High Tensile
For structural anchors, high-load assemblies, and applications where you need significantly more clamping force or tensile capacity. Grade 8.8 has a minimum tensile strength of 800 MPa and a yield strength of 640 MPa — more than double Grade 4.6. When a structural engineer specifies "high tensile rod" for an anchor bolt or moment connection, they mean 8.8.
Do not substitute 4.6 for 8.8 in structural applications. The strength difference is material. Manufactured to DIN 976 / AS 3501. Available in zinc-plated and HDG.
Stainless Steel — Grade A2 (304) and A4 (316)
For corrosion-resistance where galvanising isn't adequate. Grade 304 (A2) handles most industrial and general outdoor environments well. Grade 316 (A4) adds molybdenum, which significantly increases resistance to chlorides — it's the grade to specify for coastal, marine, food processing, pharmaceutical, and chemical plant environments.
Stainless rod is slightly lower in tensile strength than Grade 8.8 — 304 runs around 500 MPa UTS, 316 slightly less — but far outperforms galvanised in corrosive environments over time.
Brass
For electrical applications requiring non-magnetism, light corrosion resistance, or aesthetic finish. Brass rod is used in marine fittings, electrical panel grounding studs, and decorative furniture. Not for structural use.
Nylon
For electrical isolation, chemical resistance, and applications where a fastener must be non-conductive. Used in circuit boards, chemical plant, and food-grade equipment. Significantly lower strength than steel — not structural.
Grade Comparison Table
| Grade | Material | Min Tensile (MPa) | Min Yield (MPa) | Typical Finish | Best For |
|---|---|---|---|---|---|
| 4.6 | Mild steel | 400 | 240 | Zinc plate, HDG | General construction, MEP hangers |
| 8.8 | High tensile steel | 800 | 640 | Zinc plate, HDG | Structural anchors, high-load |
| A2 / 304 | Stainless steel | ~500 | ~210 | Brushed/natural | General corrosion resistance |
| A4 / 316 | Stainless steel | ~500 | ~210 | Brushed/natural | Marine, coastal, food, chemical |
| Brass | Brass alloy | ~380 | — | Natural | Electrical, decorative |
| Nylon | Polyamide | ~80 | — | Natural | Electrical isolation, chemical |
Finishes — Zinc Plated vs Galvanised vs Stainless
Even within Grade 4.6, the finish you choose makes a significant difference to how long the rod will last in the environment it's going into.
Plain / Bare Steel
No coating. Cheapest option. Suitable only for dry, indoor, protected environments — it will rust quickly in any moisture. Typically used in shop settings or as a temporary fastener.
Zinc Plated (Electro-Galvanised)
A thin electroplated zinc layer — typically 5–12 µm. Good for dry to mildly damp indoor environments. Standard for most light commercial and residential fitout work. Not suitable for outdoor or humid environments over the long term.
Hot-Dip Galvanised (HDG)
Zinc coating applied by immersion in molten zinc — typically 45–85 µm, much thicker than electroplated. Provides good long-term corrosion protection for outdoor and semi-exposed environments. This is the standard spec for commercial construction, HVAC, plumbing hangers, and most outdoor structural applications in Australia. The coating adds a small amount of bulk to the thread — use an appropriate nut that accommodates HDG rod, or the fit will be tight.
Stainless Steel 304
No separate coating — the alloy itself provides corrosion resistance through a chromium oxide passive layer. Suitable for general outdoor, marine proximity, wet areas, and mild chemical exposure. Doesn't require ongoing maintenance. Preferred for food-grade and pharmaceutical applications.
Stainless Steel 316
The marine-grade option. Molybdenum content (2–3%) provides meaningfully better chloride resistance than 304. Specify 316 for anything within a few kilometres of the coast, anything submerged or regularly wet in salt water, or any chemical/food processing application involving chlorine compounds. The price premium over 304 is significant — use it where it's genuinely needed, not as a blanket upgrade.
Metric Sizes and Standard Lengths
In Australia, threaded rod is sold in metric coarse thread as the standard. Metric fine thread is available but rarely stocked — it's a special order item for most suppliers.
Most Common Sizes in Trade Use
If you're buying threaded rod for MEP, construction, or workshop use, these four diameters cover the vast majority of applications:
- M8 — Light-duty hangers, residential plumbing, light cable tray, furniture
- M10 — Commercial plumbing hangers, medium cable tray, electrical conduit supports
- M12 — HVAC duct hangers, structural bracing, workshop and machinery applications
- M16 — Heavy HVAC plant, AHUs, structural base plates, heavy-duty anchor rods
Full Metric Range
Standard stock sizes typically run from M6 through to M30 or M36. Larger sizes — M39, M42, M48, M52, M56, M64 — are available but are usually special order from fastener specialists. The full metric coarse range is: M3, M4, M5, M6, M8, M10, M12, M14, M16, M18, M20, M22, M24, M27, M30, M33, M36, M39, M42, M48, M52, M56, M64.
Standard Lengths
Most suppliers stock threaded rod in 1 m and 3 m lengths. Some suppliers offer 2 m stock. Cut-to-length is available from most fastener specialists — useful when you need a precise length and want to avoid site waste.
Size and Load Guide
| Diameter | Pitch (coarse) | Tensile Stress Area (mm²) | Indicative SWL Grade 4.6 (kN) | Common Use |
|---|---|---|---|---|
| M8 | 1.25 mm | 36.6 | ~6.2 | Light hangers, furniture |
| M10 | 1.50 mm | 58.0 | ~9.8 | Plumbing, cable tray |
| M12 | 1.75 mm | 84.3 | ~14.3 | HVAC, workshop, general construction |
| M16 | 2.00 mm | 157 | ~26.7 | Heavy plant, structural anchors |
| M20 | 2.50 mm | 245 | ~41.7 | Heavy structural, base plates |
| M24 | 3.00 mm | 353 | ~60.0 | Large structural connections |
SWL values are indicative for Grade 4.6 rod in axial tension. Always consult a structural engineer for load-critical applications. Grade 8.8 values are approximately 2.7× higher at the same diameter.
How to Cut Threaded Rod
Cutting threaded rod is straightforward, but the method matters — a badly cut end with a crushed or burred thread makes it frustrating to run a nut on, and a thread that's too short means the nut won't develop full engagement. Here's how to do it cleanly.
The Nut Trick (Recommended)
This is the trade-standard method for getting a clean thread end every time:
- Thread two nuts onto the rod and run them past the intended cut point.
- Jam the two nuts against each other by turning them in opposite directions — this locks them in place.
- Slide the locked pair back to your cut mark. The nut face nearest the cut gives you a straight guide for your saw blade.
- Cut through the rod using a hacksaw or angle grinder, using the nut face as a guide to keep the cut square.
- After cutting, back the two nuts off past the cut end — as they unwind over the fresh cut, they reform and clean up any minor burring on the thread.
The result is a clean, usable thread end with minimal fuss. It's the same trick used by every experienced sparky, plumber, and rigger in the country.
Tool Options
- Hacksaw: Ideal for one-off cuts, softer materials (brass, stainless up to M16), or when you need a quiet, spark-free method. Clamp the rod in a vise for a straight cut. Use a bi-metal blade with 18–24 TPI for steel. See the hacksaw blade guide for TPI selection.
- Angle grinder (cutting disc): Fast for volume cutting and larger diameters. Leaves a burr that needs cleaning — use the nut trick, or dress the end with a bench grinder. See the cutting disc guide for disc selection.
- Metal chop saw: Best for workshop settings cutting multiple lengths. Gives a clean square cut. Use a metal-rated abrasive disc or cold saw blade.
- Reciprocating saw: Workable in tight spaces on site. Use a metal-rated bi-metal blade. Not as clean as a hacksaw or chop saw.
- Bolt cutters: Don't. They crush the thread end and make it unusable without re-tapping or grinding.
After Cutting
Always run a nut over the cut end before putting the rod into service. If the nut won't pass smoothly, dress the end with a fine file, bench grinder, or thread die to remove any remaining burr.
How to Join Threaded Rod (Coupling Nuts)
When you need to extend a length of threaded rod — to reach from a slab anchor to a low duct, or to join two cut lengths — the tool for the job is a coupling nut. It's also called an extension nut, long nut, rod joiner, or barrel nut.
A coupling nut is a hex nut machined to a much longer length than a standard nut — typically 3× to 5× the diameter. Both ends are fully threaded to the same pitch as the rod, so you simply thread one rod end in from each side and tighten with two spanners, jamming the rods against each other inside the nut.
For clean connections:
- Make sure both cut ends are clean and deburred before threading into the coupling nut.
- Achieve full thread engagement — the rod end should bottom out at or past the centreline of the nut.
- Use two spanners to tighten — hold the nut body, turn the rod. Don't trust finger-tight joints under load.
- For vibration environments, apply a thread-locking compound such as Loctite 222 (low-strength, removable) to the rod thread before assembly.
Reducer coupling nuts are available for joining two different diameters — for example, M12 on one end and M10 on the other. These are useful when transitioning between a structural anchor rod (M16) and a lighter hanger rod (M12).
Acme Thread — When Standard Allthread Won't Do
If you're searching for threaded rod for a CNC leadscrew, lathe repair, workbench vise, or scissor jack — standard metric allthread is the wrong product. What you need is acme thread rod.
What Is Acme Thread?
Acme thread is a trapezoidal thread form — the thread profile is a trapezoid rather than the V-shape of standard metric threads. The flank angle is 29° (compared to 60° for metric V-threads). The Australian/international equivalent is ISO trapezoidal thread (30° flank angle), which is functionally very similar and often used interchangeably in practice.
Why Acme Thread, Not Standard Allthread?
Standard V-thread (metric coarse) is designed for fastening — clamping two things together. It has a steep thread form that grips well under static load but has high friction when rotated under load, generates heat, and wears relatively quickly if used as a power-transmission screw.
Acme thread is designed for movement — converting rotation into controlled linear motion. The wider, flatter tooth profile:
- Reduces friction under load compared to V-thread
- Handles higher axial loads with less thread wear
- Self-cleans in dusty or debris-laden environments
- Supports multi-start thread configurations (2-start, 4-start) for faster linear travel per revolution
Where Acme Thread Is Used
- CNC router and mill leadscrews
- Lathe cross-slide and carriage screws
- Woodworking face vice and leg vice screws
- Scissor lifts and mechanical jacks
- Gate and valve actuator stems
- Linear actuators and positioning stages
Sourcing Acme Thread Rod in Australia
Standard metric allthread is stocked everywhere. Acme thread rod is considerably harder to find — most hardware stores and general fastener suppliers don't carry it. For AU sourcing, contact AIMS Industrial or specialist fastener suppliers. Multi-start acme rod (2-start, 4-start) is a special order item — allow lead time.
Threaded Rod vs Bolts — When to Use Each
Threaded rod and bolts solve different problems. Here's a quick guide to when each makes sense:
| Situation | Use Threaded Rod | Use a Bolt |
|---|---|---|
| Length needed exceeds standard bolt sizes | ✓ | |
| Position of nut needs to be adjustable along the fastener | ✓ | |
| Suspending from above (hanger application) | ✓ | |
| Connecting two surfaces without a head clearance | ✓ | |
| Chemical anchor / epoxy set into concrete | ✓ | |
| Standard through-bolt, flange bolt, or machine fastening | ✓ | |
| Quick assembly where head clearance exists | ✓ | |
| Tightening with a single tool from one side | ✓ |
Buying Guide — What to Specify
When ordering threaded rod, specify these four things and you'll get the right product every time:
- Diameter: M8, M10, M12, M16, M20 etc.
- Grade: 4.6 (general), 8.8 (structural/high load), A2-304 (corrosion resistance), A4-316 (marine/coastal)
- Finish: Zinc plated (dry indoor), HDG (outdoor/construction), Stainless (corrosive environments)
- Length: 1 m, 2 m, 3 m stock, or cut to length
If you're not sure which grade or finish suits your application, contact the AIMS team with a description of the environment and load — we'll point you in the right direction.
Browse the AIMS Industrial allthread range, including Grade 4.6 galvanised, Grade 8.8 high tensile, and stainless steel threaded rod.
Accessories and Hardware for Threaded Rod
Threaded rod rarely works alone — it's part of a system. Here's the hardware you'll need alongside it, and when each piece is used.
Hex Nuts
The standard nut for threaded rod. Use two hex nuts per connection point — one to locate the fitting or bracket, one as a jam nut to lock the first in place and prevent it from working loose under vibration or load. For HDG rod, use HDG nuts (the zinc coating slightly increases the rod's effective diameter — standard zinc-plated nuts will be tight). Match grade: use Grade 4 or 5 nuts on Grade 4.6 rod; use Grade 8 nuts on Grade 8.8 rod.
Nyloc Nuts (Nylon Insert Lock Nuts)
A nylon insert in the top of the nut grips the thread and resists loosening under vibration — without needing a second jam nut. Ideal for dynamic or vibrating applications: HVAC fans, machinery mounts, motor bases. Nyloc nuts are single-use by design — the nylon compresses on first use. Don't re-use a nyloc nut that's already been run down a thread. See the fastener reference guide for full nut type coverage.
Flat Washers
Used wherever a nut bears against a surface that might deform under load — timber, softer metals, fibreglass, rubber gaskets. The washer distributes the clamping load over a larger area. Use hardened flat washers on Grade 8.8 rod to prevent the nut from pulling through the surface. DIN 125 flat washers (metric) are the standard.
Spring Washers
A split ring washer that applies a spring load against the nut and surface, reducing the tendency to loosen under vibration. Used in machinery, engine mounts, and vehicle applications. Less effective than a Nyloc or double-nut arrangement for heavy vibration — but fast to assemble and good for moderate conditions.
Coupling Nuts (Extension / Joiner Nuts)
Long hex nuts threaded along their full length, used to join two lengths of threaded rod end-to-end. Also called extension nuts, rod joiners, or barrel nuts. Standard metric coupling nuts run 3–5× the nominal diameter in length. When joining rod in a hanger application, ensure the coupling nut is rated for the load in tension — not all coupling nuts are tested for structural applications. See the dedicated section above for joining technique.
Wing Nuts
Hand-tightenable nuts — no tool required. Used for panels, covers, guards, and other components that need to be removed regularly. Not for structural or high-load use. M6 and M8 wing nuts are common in cabinet and enclosure work.
T-Nuts and Square Nuts
Used in applications where the nut must resist rotation — wood joints, strut channel (where a square nut slides into the channel profile), and T-slot aluminium extrusion. Square nuts are the standard for most strut channel systems used with threaded rod.
Rod Hanger Clamps and Beam Clamps
Beam clamps bolt to structural steel flanges and provide an attachment point for hanger rod — used in HVAC and fire protection installations where there's no concrete soffit above. A range of clamp sizes suits different beam flange thicknesses. Most accept M10 or M12 rod directly through a threaded eye or clevis hole.
Concrete Anchors and Wedge Anchors
For attaching hanger rod to concrete soffits, mechanical wedge anchors or chemical anchor systems are used. Wedge anchors (also called expansion anchors) are fast to install — drill hole, insert anchor, tighten nut. Chemical anchors (epoxy anchors) give higher loads and work in cracked concrete or close to edges where expansion anchors fail. The threaded rod is either part of the wedge anchor assembly, or is set separately into a chemical anchor system. For structural applications, specify the anchor to the concrete strength and required load — don't guess.
Installation Tips and Common Mistakes
Most threaded rod installation problems are simple to avoid if you know what to watch for. Here are the common ones.
Not Using a Jam Nut
A single nut run onto threaded rod will loosen under vibration over time. Always use two nuts at each connection point, or a Nyloc nut. Thread the first nut to position, then wind the second nut down against it and hold the first nut with one spanner while tightening the second with another. This locks the pair — they can't turn independently. The two-nut method is faster and cheaper than discovering a dropped duct fitting six months later.
Using Grade 4.6 Where 8.8 Is Specified
Grade 4.6 is fine for MEP hangers, shelf uprights, and general non-structural work. It is not a substitute for Grade 8.8 where an engineer or standard has specified high tensile rod — in anchor bolts, structural connections, or load-rated hanger systems. The strength difference is more than 2:1. If the spec says 8.8, use 8.8.
Wrong Nut for HDG Rod
Hot-dip galvanised rod has a thicker, more irregular thread surface than zinc-plated rod. Standard zinc-plated nuts can bind — or the threads can strip — if forced onto HDG rod. Use HDG nuts (or specify "HDG oversize") with HDG rod. They're tapped slightly larger to account for the coating. The fitting should still be firm, not sloppy — if it's too loose, you have a mismatch.
Insufficient Thread Engagement
A nut needs adequate thread engagement to develop its full rated load. The rule of thumb: minimum thread engagement equals the nominal diameter — so an M12 nut needs at least 12 mm of rod engagement, and preferably more. On a coupling nut joint, make sure each rod end runs at least to the centreline of the coupling nut. Short engagement is one of the most common causes of nut strip-out under load.
Burred or Damaged Thread End
A cut or knocked thread end that hasn't been cleaned up will cause a nut to jam partway, which either cross-threads the nut or causes you to strip it while trying to force it. Clean every cut end before assembly. Run a nut over it first — if it catches, use a thread file, die, or the nut trick to clean it before it becomes your problem inside a hanger assembly in the ceiling.
Mixing Metric and Imperial Thread
Metric and imperial (UNC/UNF) threaded rod look almost identical to the naked eye, and you will occasionally get both on site. A metric nut will not fit an imperial rod and vice versa — forcing it strips both. When you're unsure, use a thread gauge, or count the threads per 25 mm against a known pitch chart. The most common confusion is M12 (1.75 mm pitch) vs 1/2" UNC (12.7 TPI / 2.0 mm pitch) — similar diameter, different pitch.
Ignoring Corrosion Requirements
Zinc-plated rod installed outdoors, in roof spaces, near the coast, or in humid environments will rust within months. The corrosion spreads from the cut ends first — zinc plating is damaged when the rod is cut, and the bare steel underneath is immediately exposed. Either use HDG or stainless, or apply cold galvanising compound to cut ends at minimum. For coastal or marine applications, 316 stainless is the only acceptable long-term solution.
Standards and Compliance
For most trade and construction applications in Australia, the relevant standards for threaded rod are:
- AS 2451 — Metric hex nuts, including those used with threaded rod. Sets dimensional and mechanical requirements.
- AS 3501 — Metric bolts, screws, and studs, including high-tensile threaded rod specifications.
- DIN 975 / DIN 976 — German industry standards widely referenced by Australian fastener suppliers for threaded rod dimensions, thread pitch, and mechanical properties. Most Australian threaded rod is manufactured to DIN 976 specifications.
- AS 3569 — Not directly for threaded rod, but relevant when threaded rod is used in wire rope or rigging assemblies.
- National Construction Code (NCC) / Building Code of Australia (BCA) — Sets requirements for fastener grades in structural applications. Where threaded rod is used as a structural element, NCC compliance requires it to be specified and installed to the relevant structural engineering standard.
For any application where threaded rod forms part of a structural connection, load-rated hanger system, or fire protection assembly — get the engineering right. Threaded rod is cheap; engineering failures are not.
Frequently Asked Questions
What is the difference between threaded rod, allthread, and studding?
They're all the same product — a length of metal bar stock threaded along its full length with no unthreaded shank or head. Threaded rod is the standard engineering term. Allthread (or all thread rod / ATR) is the common trade abbreviation. Studding is the UK trade term widely used in Australian plumbing and electrical work. All three mean fully threaded bar — the name varies by trade and region, not by product.
What is Booker rod? Is it the same as Brooker rod?
Yes — Booker rod and Brooker rod are the same thing, just two spellings of the same Australian trade term. Both refer to standard fully threaded rod (allthread). The term is believed to derive from Booker Bros, a major Australian building materials distributor, whose branded threaded rod became so ubiquitous that the name stuck as the generic trade term for the product — similar to how 'Biro' became the word for a ballpoint pen. If someone asks for Booker or Brooker rod, give them standard galvanised allthread in the diameter they need.
What is the difference between Grade 4.6 and Grade 8.8 threaded rod?
Grade refers to strength. Grade 4.6 is mild steel with a minimum tensile strength of 400 MPa — suitable for general construction, MEP hangers, and non-structural fastening. Grade 8.8 is high tensile steel with a minimum tensile strength of 800 MPa — more than double the strength of 4.6 — and is specified for structural anchor bolts, high-load clamping, and any application where failure would have safety consequences. Do not substitute Grade 4.6 for Grade 8.8 in structural or load-rated applications.
Should I use galvanised or stainless threaded rod outdoors?
It depends on the environment. Hot-dip galvanised (HDG) rod is adequate for most Australian outdoor construction environments — exposed but not directly coastal. For coastal locations (within a few kilometres of the ocean), food processing, pharmaceutical plants, or chemical environments involving chlorides, specify stainless steel Grade 316 (A4). Grade 304 stainless is a good middle ground for general corrosion resistance without the cost of 316. For dry, protected indoor environments, zinc-plated rod is sufficient.
What size threaded rod do I need for pipe hangers?
M10 is the standard size for most commercial plumbing pipe hangers — it provides adequate strength for typical pipe diameters and is compatible with most hanger bracket systems. M8 is suitable for light-duty residential pipework. For larger pipe diameters (150 mm and above) or heavy services, M12 is common. Always check the hanger bracket manufacturer's specification for the required rod diameter and grade.
How do you cut threaded rod without ruining the thread?
Use the nut trick: thread two nuts onto the rod and lock them against each other (jam nut technique) at the cut mark. Use the nut face as a guide for your hacksaw or angle grinder. After cutting, back the locked nuts off past the cut end — as they unwind over the freshly cut thread, they reform and clean any minor burring. Always run a loose nut over the finished end to confirm it threads smoothly before putting the rod into service.
What is a coupling nut and how do you use it to extend threaded rod?
A coupling nut (also called an extension nut, long nut, or rod joiner) is a long hex nut threaded along its full length. To join two lengths of threaded rod, thread one rod end in from each side of the coupling nut until both rods meet approximately at the centre, then tighten with two spanners — one holding the nut, one turning the rod. Ensure the cut ends are clean and deburred before assembly, and achieve full thread engagement for a reliable connection.
Can I use threaded rod as an anchor bolt in concrete?
Yes — post-installed anchor rods are a common application. The rod is set into a core-drilled hole using two-component epoxy adhesive (such as Loctite 5088 or Ramset HIT-RE 500) and allowed to cure before loading. The grade of rod must match the structural specification — Grade 8.8 is typically required for structural anchors. Always follow the adhesive manufacturer's installation instructions for hole diameter, embedment depth, cleaning procedure, and cure time, and consult a structural engineer for load-critical anchor design.
What is the difference between acme thread and standard metric threaded rod?
Standard metric threaded rod has a V-shaped thread profile (60° flank angle) designed for fastening — clamping two parts together under static load. Acme thread has a trapezoidal profile (29° flank angle) designed for power transmission — converting rotation into controlled linear motion with reduced friction and better wear characteristics. If you need a leadscrew for CNC, a lathe carriage screw, or a vise screw, you need acme thread rod, not standard allthread.
What does 'hanger rod' mean?
Hanger rod is the HVAC and fire protection industry term for threaded rod used to suspend ductwork, pipe, cable tray, and mechanical plant from structural steel or a concrete soffit. Hanger rod is typically Grade 4.6 HDG in M10 or M12, passed through a concrete anchor or beam clamp at the top and terminated with a nut and hanger bracket at the bottom. The length is adjusted by running the nut up or down the rod before locking in position.
What is stud rod?
Stud rod is another name for threaded rod — used primarily in the MEP (mechanical, electrical, and plumbing) trades. The term emphasises the rod's function as a suspension stud — passed through a strut channel fitting or hanger bracket — rather than its product form. It means the same product as allthread, studding, or threaded bar.
Can I use threaded rod instead of a bolt?
Yes, with two nuts — one on each side of the joint, tightened together to clamp. Threaded rod with two nuts is functionally equivalent to a bolt and nut, and is preferred when you need an adjustable length, when standard bolt lengths are insufficient for your joint thickness, or when you need a fastener that can be positioned anywhere along its length. For volume production, a headed bolt is faster to install. For adjustment, custom lengths, or through-bolt applications with no head clearance, threaded rod is the better choice.
What size threaded rod is used for HVAC duct hangers?
M10 and M12 are the most common sizes for commercial HVAC duct hangers in Australia. M10 HDG rod is standard for light to medium rectangular ductwork (up to around 600 mm wide). M12 is used for heavier duct runs, larger dimensions, and where spans between hanger points are greater. For heavy plant items — large AHUs, rooftop units — M16 or M20 Grade 8.8 rod may be required. Check the duct weight and hanger spacing against the hanger system manufacturer's load tables.
Is 316 stainless threaded rod worth the extra cost over 304?
Only if your environment genuinely requires it. Grade 304 handles most corrosive environments well — general outdoor, wet areas, food prep surfaces, mild chemical exposure. Grade 316's additional molybdenum provides meaningfully better chloride resistance, which matters in coastal or marine settings, salt water immersion, swimming pool environments, and food processing plants using chlorinated cleaning compounds. If you're more than a few kilometres from the coast and not dealing with chlorinated chemicals, 304 is usually adequate and significantly cheaper. When in doubt, go 316 — the cost difference is much smaller than a replacement job in a failed anchor.
Where can I buy threaded rod in Sydney?
AIMS Industrial stocks Grade 4.6 galvanised, Grade 8.8 high tensile, and stainless steel threaded rod in common metric sizes from our Milperra warehouse. Orders placed before our cut-off can be dispatched same day. We supply tradespeople, engineers, and procurement teams across Greater Sydney and Australia-wide. Browse our allthread range online or contact our team for cut-to-length, large quantities, or sizes not shown online.