Safety Tips

Grinding Wheel Safety: Selection, Mounting & AS 1788

Angle grinders sit at the top of Safe Work Australia's serious-injury list every year. Most of the harm comes from wheel selection mistakes, missing or removed guards, wrong RPM, or operators not bracing for kickback. None of those failure modes are mysteries — they all sit inside AS 1788.2 Abrasive products — Safety requirements for the use of abrasive products, which is the controlling standard for grinding wheel use in Australia. This guide walks through how to choose the right wheel, inspect it before mounting, match it to the grinder's RPM, mount it correctly, operate it safely, and what PPE is non-negotiable. It's written for fabricators, mechanical fitters, automotive workshops, plumbers, electricians, maintenance teams, and the DIYer doing more than the occasional cut. If you cut concrete, stone or stainless steel, the silica and manganese dust sections are essential reading. For wheel selection by spec code, type and grit, our companion Grinding Discs & Wheels: Types, Spec Code & Selection Guide covers the product side in depth. This guide is the safety hub. Grinding Wheel Quick Safety Checklist Run this checklist before every cut or grind: # Check 1 Wheel max RPM ≥ grinder rated RPM. Never the other way around. 2 Wheel diameter, thickness and bore match the grinder spec. 3 Wheel is the right type for the job (cut-off vs grinding vs flap). 4 Visual inspection: no cracks, chips, blotter damage, or moisture marks. 5 Ring test on vitrified wheels — clear ringing tone, not a dull thud. 6 Correct flanges and blotters fitted. Locking nut firm — never over-tightened. 7 Guard fitted, positioned between the wheel and operator. 8 Workpiece secured in a vice or with clamps. Never hand-held. 9 Full PPE on: face shield + safety glasses, P2 minimum respirator, hearing, leather gloves and apron, enclosed boots. 10 Area clear of flammables. Hot work permit in place if required. 11 Two-handed grip. Side handle fitted and in use. 12 Let the wheel reach full speed before contact. Let it stop fully before setting down. The AS 1788.2 Framework AS 1788.2 Abrasive products — Safety requirements for the use of abrasive products is the Australian Standard that governs how grinding and cutting-off wheels must be selected, mounted, used and stored. It applies to depressed centre wheels, cutting-off wheels, straight wheels, and bonded abrasive products used on portable and bench grinders. The standard sits alongside several other AS/NZS standards that all apply when grinding work is happening: AS/NZS 1336 — Eye and face protection — Guidelines: selection guidance for face shields, goggles and glasses. AS/NZS 1337 series — Eye protectors: performance and marking. Look for the AS/NZS 1337.1 mark on safety glasses and AS/NZS 1337.6 for prescription versions. AS/NZS 1270 — Acoustics — Hearing protectors: SLC80 Class system for muffs and plugs. AS/NZS 1715 — Selection, use and maintenance of respiratory protective equipment and AS/NZS 1716 — Respiratory protective devices: the P1/P2/P3 filter classifications. AS/NZS 2161 series — Occupational protective gloves: general requirements and mechanical hazards (EN 388 family). AS 1788.2-1987 (the grinding wheels application/operation standard remains in force). AS/NZS 1337.1:2010+Amdt 2:2018, AS/NZS 1716:2012 (R2024), AS/NZS 1270:2002 (R2014). WHS legislation in every Australian state and territory makes compliance with these standards a duty for PCBUs (Persons Conducting a Business or Undertaking). Practically that means: train operators, supply the right wheels and PPE, maintain the tools, and keep records. Wheel Types — At a Glance Pick the wrong wheel type and you've broken the standard before you've even started. The four common bonded abrasive types you'll meet on a portable grinder are: Type Profile Use Common bonded thickness Type 1 Straight, flat Cutting-off (bench cut-off saws, some portables) 1.6–3.2 mm Type 27 Depressed centre Grinding (most common on 4½–9″ angle grinders) 6.0–6.4 mm Type 41 Flat cut-off, reinforced Cutting-off ONLY — never use on the side 1.0–3.2 mm Type 42 Depressed centre cut-off Cutting + light grinding on the edge — still primarily a cutting wheel 2.5–4.5 mm Flap disc Overlapped abrasive flaps on backing plate Grinding + finishing in one — gentler on the workpiece than a Type 27 n/a For the deeper selection logic (grit, bond, application by metal type), see our Grinding Discs & Wheels Selection Guide. For flap disc-specific selection, see the Flap Disc & Abrasive Sanding Guide. Browse current stock: Cutting Wheels, Grinding Wheels & Accessories, Flap Discs, or the full Abrasives range. Wheel Specifications — Diameter, Thickness, Bore Every wheel is stamped with three physical numbers that must match the grinder you're putting it on. Get any of the three wrong and the wheel either won't fit or will fail in service. Diameter The wheel's outside diameter — 100 mm (4″), 115 mm (4½″), 125 mm (5″), 180 mm (7″), 230 mm (9″) are the common Australian sizes. The grinder's guard is sized for a specific diameter range. A 4½″ guard cannot safely cover a 5″ wheel. Thickness Cut-off wheels are typically 1.0–3.2 mm. Grinding wheels (depressed centre) are 6.0–6.4 mm. A 1 mm cut-off wheel will cut faster and waste less metal but is more fragile under side load — and side load on a cut-off wheel is forbidden anyway (see below). Bore The centre hole. The Australian standard bore for angle grinder wheels is 22.23 mm (sometimes labelled 7/8″). Some bench wheels use 31.75 mm (1¼″) or 25.4 mm (1″). Never bore out, ream, or shim a wheel to fit a spindle it wasn't manufactured for. Matching Wheel RPM to Grinder RPM This is the single most ignored safety rule in workshops. The wheel's maximum operating RPM must always equal or exceed the grinder's rated speed. Run a wheel above its rated RPM and the centrifugal stresses can exceed the bond strength — the wheel breaks apart. Grinder size Typical no-load RPM Wheel RPM required 4″ (100 mm) 13,500–15,300 ≥ rated grinder RPM 4½″ (115 mm) 11,000–13,300 ≥ rated grinder RPM 5″ (125 mm) 11,000–12,200 ≥ rated grinder RPM 6″ (150 mm) 9,000–10,000 ≥ rated grinder RPM 7″ (180 mm) 8,000–8,500 ≥ rated grinder RPM 9″ (230 mm) 6,500–6,650 ≥ rated grinder RPM The maximum operating speed is stamped on the wheel itself and printed on the blotter (the paper washer bonded to the wheel face). If you can't read either, do not mount the wheel. Pre-Use Inspection — Visual and Ring Test Visual inspection Before every mount, look at the wheel for: Hairline cracks running from the bore outward (the most dangerous fault — these propagate under load) Chips on the edge greater than ~3 mm Damaged or partly detached blotters Moisture stains (water weakens vitrified bond — wheel is compromised) Date code or batch markings — some resin-bonded wheels carry an expiry date because resin degrades over time The ring test (vitrified wheels only) Suspend the wheel through the bore on a wooden dowel or screwdriver shaft. Tap the wheel gently with a non-metallic implement (the wooden handle of another tool) at about 45° from each side. A sound wheel rings clearly. A cracked wheel produces a dull or flat thud. Repeat from four positions around the wheel. The ring test does not work on organic (resin or rubber) bonded cut-off wheels — they always sound dull. Visual inspection plus the date code is the assessment method for those. Wheel Storage Wheels are not consumables you toss in a drawer. Store them properly and they last; store them badly and they fail in service. Keep them in the original packaging until first use Store flat (stacked carefully with thin separators) or vertical on edge in a rack Never stack heavy items on top — even cardboard boxes Keep them dry. Humidity attacks vitrified wheels and corrodes the metal reinforcement on cut-off wheels Keep them away from solvents, fuels and oils — these attack resin bonds Storage temperature 5–30 °C. Sub-zero or above 40 °C accelerates resin degradation First-in-first-out rotation — use the older stock before the newer when both are within date A simple wall-mounted timber or steel rack with vertical slots is the standard workshop solution. Browse Abrasives for current stock if your wheels are aged past their date code. Mounting the Wheel Mounting is where small mistakes become serious failures. The procedure: Unplug or remove the battery — never change a wheel on a live tool Press the spindle lock (most angle grinders), or hold the spindle with a pin spanner Loosen the locking flange with the manufacturer's pin spanner. Use the right spanner — pliers will round the flange Remove the existing wheel. Wipe the spindle, inner flange and locking flange clean of swarf and debris Inspect the new wheel (visual + ring test) Place the inner flange on the spindle Place the wheel against the inner flange — orientation depends on wheel type (Type 27 depressed centre faces outward) If a blotter or paper washer is supplied bonded to the wheel, leave it in place; if it's loose, fit it between the wheel and the locking flange Fit the locking flange and tighten with the pin spanner — firm only, not over-tight. Over-tightening distorts the flanges and pre-stresses the wheel, weakening it Refit the guard and confirm it covers at least 180° of the wheel between the wheel and the operator Restore power. Run the grinder at full speed (with the wheel pointed away from the operator) for at least 30 seconds before first use — listen for vibration, wobble, or unusual noise Safe Operation — Cut-Off vs Grinding Cut-off wheels Warning: Cut-off wheels (Type 1 and Type 41) are only safe to use on the edge. Never load them on the flat side. The wheel is engineered to take radial compression, not side loading. Side loading a cut-off wheel will break it. The fragments leave the wheel at the wheel's surface speed — for a 4½″ wheel at 13,000 RPM that's around 250 km/h. Cut-off technique: Mark the cut line clearly Secure the workpiece in a vice or with clamps so the offcut won't pinch the wheel Let the wheel reach full speed Apply the wheel to the work at 90° to the cut line, only on the edge Light pressure — let the wheel cut at its own speed. Forcing the wheel slows it and overheats the bond If the wheel starts to pinch in the cut, stop and re-secure the offcut Withdraw before letting off the trigger; let the wheel coast down clear of the work Grinding wheels (Type 27) Grinding wheels are designed to work on their face at a shallow angle to the workpiece: Working angle: 15–30° face to workpiece (above 30° lifts the wheel; below 15° tries to use the wheel like a cut-off — both wrong) Sweep the wheel across the work; don't rest it in one spot Light pressure — heat builds quickly and discolours both wheel and workpiece Two-handed grip with the side handle fitted Workpiece secured in a vice or clamped — never hand-held Flap discs Flap discs are more forgiving than Type 27 wheels. The flap structure lays flat against the work so the working angle can be 5–15° (gentler grind, smoother finish). They're a good choice for finishing welds and removing surface rust. See the dedicated Flap Disc Guide for selection. Kickback Hazards Warning: Kickback is the most common cause of serious angle grinder injury. The wheel grabs the workpiece — either because the wheel binds in a cut, hits a hard inclusion, or you angle it into a corner — and the grinder is thrown back violently at the operator. With a 4½″ grinder this can put the spinning wheel into the operator's face or throat in a fraction of a second. What causes kickback: The wheel pinches in the cut as the offcut sags Plunge-cutting into corners or against a step where the wheel binds Using the wrong section of the wheel (top half of the wheel grabs more than the bottom) Twisting the grinder out of the cut line Working with a damaged wheel that catches in the cut How to prevent it: Two-handed grip, always. Side handle fitted to the threaded port — not optional Position your body to the side of the wheel's rotation plane, not in line with it Brace your stance — feet shoulder-width, knees soft Cut on the underside of the wheel (the part rotating away from you) on free work; cut on the topside when the work is fixed Plan the cut so the offcut falls away clean, not pinches For deep cuts, multiple shallow passes — not one deep one Keep both hands on the tool until the wheel has fully stopped Wheel Breakage — Why Face Protection Matters Warning: A 4½″ wheel at 13,000 RPM has a surface speed of approximately 78 m/s — about 280 km/h. Fragment velocity in a wheel break is in that order. Safety glasses alone do not stop a wheel fragment to the face. AS/NZS 1336 guidance is face shield + safety glasses combined. Wheels can break from: Exceeding the rated RPM Side loading a cut-off wheel Mounting a cracked or moisture-damaged wheel Over-tightening the locking flange Pinching in the cut Striking the workpiece or another hard object at speed Fragments travel in the plane of the wheel — which is why the guard MUST be positioned between the wheel and the operator. The guard contains roughly half the wheel's plane; the rest is contained by distance, body positioning, and PPE. PPE — What's Required The PPE stack for grinding work, working from head down: Body part PPE Standard Eyes Safety glasses with side shields (medium impact rating minimum) AS/NZS 1337.1 Face Full face shield over the safety glasses AS/NZS 1337.1 / AS/NZS 1336 guidance Hearing Class 4 or 5 earmuffs OR earplugs depending on tool noise (4½″ grinders typically 95–105 dB(A)) AS/NZS 1270 Respiratory P2 disposable minimum; P3 for stainless, concrete, stone, or extended dusty work AS/NZS 1715 / 1716 Hands Leather rigger gloves OR heavy mechanical cut-resistant gloves (Cut Level C or D under EN 388) AS/NZS 2161 series Body Cotton drill or leather welding-style jacket. No synthetics (melt risk from sparks) — Legs Cotton drill workwear or leather chaps for heavy work. Cuff inside the boot — Feet Enclosed safety boots with steel or composite toe cap, AS/NZS 2210.3 marked AS/NZS 2210.3 Browse current PPE stock: Eye Protection, Face Protection, Ear Protection, Respiratory Protection, Welding Gloves, Cut-Resistant Gloves, Hand Protection, Workwear, and the broader Safety range. For the deep-dive on glove selection and cut levels, see the Work Gloves Guide. For respirator P1/P2/P3 selection, see the Respirator Guide. For lens types and lens ratings, see the Safety Glasses Guide. Silica Dust — The Silent Killer Warning: Cutting concrete, brick, stone, render, tile, fibre cement, or composite stone releases respirable crystalline silica (RCS). Long-term exposure causes silicosis — irreversible lung scarring — and increases lung cancer risk. The Safe Work Australia workplace exposure standard for RCS is 0.05 mg/m³ over 8 hours. Dry-cutting concrete with a 4½″ grinder can produce RCS concentrations many times that level within minutes. If you cut any silica-bearing material with a grinder: Use wet cutting wherever possible. Diamond blades with water feed suppress dust at source If dry cutting is unavoidable, attach on-tool dust extraction (M or H class vacuum) with a shrouded guard Minimum respirator: P2 half-face. For extended dry cutting: P3 half-face or full-face PAPR Wet down the work area before, during and after — don't sweep dry; HEPA vacuum Change out of dusty clothing before leaving site; don't take dust home Australian state regulators are auditing silica compliance hard since 2024 — keep records of training, dust controls, and air monitoring where applicable Manganese dust on stainless Grinding or cutting stainless steel releases manganese, chromium and nickel oxides. Manganese has a respirable WES of 0.02 mg/m³ TWA — extremely low. P2 minimum, P3 or PAPR preferred. Adequate ventilation or local exhaust is essential for extended stainless work. Hot Work Considerations Grinding sparks travel further than people expect — typical 8–10 m, further with high-carbon steel or stainless. Sparks at the end of their flight can still ignite paper, sawdust, oily rags, solvent vapour, or LPG/petrol vapour. Before any grinding work: Clear flammables and rags within a 10 m radius of the grinding position Cover or wet down any flammables that can't be moved (timber framing, paint stores) Confirm fire extinguishers are within reach — ABE or water mist depending on what's nearby If working in a permit area (refineries, fuel storage, confined spaces, hot work zones, industrial sites), get the hot work permit in writing first Brief any fire watch on what to do and where the extinguisher is Inspect the area 30+ minutes after work finishes — embedded sparks can smoulder before they ignite Our dedicated guide: When You Need a Hot Work Permit. Companion welding safety standards: Welding Safety Guide: PPE, Fume, Hot Work & AS Standards. Run-Up & Coast-Down Two simple discipline rules that prevent the majority of wheel-engagement injuries: Run-up After mounting a new wheel, run the grinder at full no-load speed for at least 30 seconds with the wheel pointed away from the operator and any other people. Listen for vibration, wobble, unusual noise. If the wheel is going to fail from a manufacturing defect, undetected crack, or moisture damage, this is when it does — and you want that energy going into the guard, not into your work. Coast-down When work is finished: Lift the wheel clear of the workpiece BEFORE releasing the trigger Let the wheel coast to a complete stop in the air Do not set the grinder down with the wheel still spinning — wheels grab into benches, fly off corners, and snag clothing or cables Keep both hands on the tool until the wheel is stopped Most grinders coast for 8–15 seconds. Patience here is free; broken wheels and damaged work are not. When NOT to Use the Grinder Stop and reassess if any of these apply: Wrong wheel for the job — never grind on a cut-off wheel, never cut on a Type 27 grinding wheel's side Wheel rated below grinder RPM Damaged wheel — any crack, chip > 3 mm, blotter damage, or moisture mark Past date code on resin-bonded wheels Guard missing, broken, or modified — removing the guard to "see better" is a frequent fatality cause; do not Side handle missing — kickback control fails without the second grip Trigger or lock-on switch sticking or modified Power cable damaged or cord switch faulty Battery showing damage, swelling or excessive heat on cordless tools Operator untrained, fatigued, or under medication that affects co-ordination Workpiece unable to be secured — never hand-hold work Flammable atmosphere nearby — fuel station, solvents, dust risk — without a permit and controls AIMS' Note on Grinding Wheel Selection The hardest part of buying grinding wheels is matching the wheel to the job and the grinder you're using. When in doubt, ring us before you order — it's faster than returning the wrong product. What we'll ask: Grinder make, model and rated RPM Grinder size — 4″, 4½″, 5″, 7″ or 9″ Application — cutting steel, grinding welds, cutting stainless, cutting concrete, finishing fabrication Material being worked — mild steel, stainless, aluminium, concrete, masonry, hardwood, plastic Duty — occasional, daily production, heavy industrial From that we'll match wheel type, diameter, bore, thickness, grit, bond and brand. AIMS stocks Klingspor, Norton, Pferd, Flexovit, Hi-Tech and other Australian-distributed brands across cutting wheels, grinding wheels, flap discs and the wider abrasives range. Phone (02) 9773 0122 or use our contact page. Grinding Wheel Safety FAQ What is AS 1788.2 and why does it matter? AS 1788.2 is the Australian Standard that governs the safe use of abrasive products including cutting-off and grinding wheels. It sets the rules for selection, inspection, mounting, RPM matching, guarding, and storage. WHS legislation in every Australian state and territory makes PCBUs (employers and self-employed contractors) responsible for ensuring compliance — train operators, supply correct PPE, and maintain tools. Can I use a cut-off wheel for grinding if I'm careful? No. Cut-off wheels are engineered for radial loading only — applying side pressure (which is what grinding does) can break the wheel. A 4½″ wheel at 13,000 RPM throws fragments at around 250 km/h. Use a Type 27 depressed centre wheel or a flap disc for grinding. Type 42 is the only wheel rated for both cutting on the edge and light grinding, and even then it's primarily a cutting wheel. What RPM should my wheel be rated for? The wheel's maximum operating RPM must always be equal to or greater than the grinder's rated no-load speed. For a 4½″ angle grinder at 12,000 RPM, the wheel must be rated 12,000 RPM or higher. The wheel's maximum RPM is stamped on the wheel itself and printed on the blotter. If you can't read either, don't use the wheel. How do I do a ring test? Suspend the wheel through the bore on a wooden dowel or screwdriver shaft so it hangs free. Tap the wheel gently with a non-metallic implement (the wooden handle of another tool) at about 45° from each side. A sound wheel rings clearly. A cracked wheel produces a dull or flat thud. Repeat from four positions. Ring test works on vitrified wheels only — organic resin or rubber bonded cut-off wheels always sound dull, so they're assessed by visual inspection plus the date code instead. Why is over-tightening the locking flange a problem? Over-tightening distorts the flanges, which pre-stresses the wheel before it even starts spinning. That stress adds to the centrifugal stress in service and can take the wheel above its strength limit at normal operating RPM. Tighten the locking flange firm only — use the manufacturer's pin spanner, not pliers or a hammer. What PPE is essential for grinding? Safety glasses (AS/NZS 1337.1 medium impact minimum) plus a full face shield over them, hearing protection (Class 4 or 5 muffs or plugs), P2 respirator minimum (P3 for stainless, concrete, stone, or extended dry work), leather rigger gloves or heavy cut-resistant gloves (EN 388 Cut Level C or D), cotton drill or leather workwear, enclosed safety boots AS/NZS 2210.3. Safety glasses alone do not stop a wheel fragment — face shield is non-negotiable. Can I cut concrete with an angle grinder? Yes, with a diamond cut-off blade rated for the grinder's RPM and proper silica dust controls. Wet cutting is preferred — diamond blades with water feed suppress respirable crystalline silica at source. If dry cutting is unavoidable, use on-tool dust extraction (M or H class vacuum) with a shrouded guard, plus P2 respirator minimum (P3 preferred). Respirable crystalline silica has a workplace exposure standard of 0.05 mg/m³ over 8 hours — dry cutting with a 4½″ grinder can exceed that within minutes. What causes kickback and how do I prevent it? Kickback happens when the wheel grabs the workpiece — usually because the wheel pinches in a cut as the offcut sags, the wheel hits a hard inclusion, or you angle into a corner where the wheel binds. Prevention: two-handed grip with the side handle fitted, stand to the side of the wheel's rotation plane (not in line), brace your feet, plan the cut so the offcut falls away clean, and for deep cuts use multiple shallow passes rather than one deep one. How long do grinding wheels last in storage? Vitrified bonded wheels are dimensionally stable for years if stored dry, away from solvents, and at 5–30 °C. Resin-bonded wheels (most cut-off wheels) typically carry a date code and should be used within 2–3 years of manufacture — resin degrades over time, even unused. Check the date code stamped on the wheel or printed on the blotter. Rotate stock first-in-first-out. Can I remove the guard to see the work better? No. Removing the guard is one of the most common causes of fatal angle grinder injuries. The guard contains roughly half the wheel's plane in a break event, and positions the wheel away from the operator's body. If you can't see the cut line clearly, change your body position, add lighting, or use a smaller wheel — never remove the guard. What's the difference between a P2 and P3 respirator? P2 respirators filter at least 94% of airborne particles down to 0.3 microns; P3 filters at least 99.95%. For most grinding on mild steel, a P2 disposable half-face is adequate. For stainless (manganese, chromium oxides), concrete (silica), or extended dry work, step up to P3 — half-face or full-face PAPR. Both must comply with AS/NZS 1716 and be selected per AS/NZS 1715 fit and use guidance. Full P1/P2/P3 selection in our Respirator Guide. Do I need a hot work permit to use an angle grinder? Depends on where you are. In refineries, fuel storage areas, confined spaces, gas pipeline corridors, or sites under a formal hot work program, yes — a permit is required. In a normal workshop or open site, no, but you still need a fire watch, cleared work area (10 m radius minimum), and extinguishers within reach. Our Hot Work Permit guide walks through where permits apply. How often should I replace my grinding wheel? When it's worn to the manufacturer's minimum diameter (usually marked or readable as a coloured ring inside the wheel), when it's been visually damaged, when the date code has passed (for resin-bonded), or when the cut quality has dropped to the point where you're forcing the wheel. Don't keep undersized wheels in service — the smaller the wheel, the higher the RPM relative to its strength margin. Are flap discs safer than Type 27 grinding wheels? Flap discs are easier and gentler to use — the overlapped abrasive flaps lay flat against the workpiece so the working angle can be 5–15° rather than 15–30°. They're also less prone to kickback. But the same PPE rules apply, the same RPM matching applies, and the same guard and side handle requirements apply. They're not a substitute for proper technique. Can apprentices use angle grinders? Yes, once trained and competent. WHS rules require apprentices and trainees to be trained, supervised, and assessed as competent before unsupervised use. PCBUs must keep training records. AIMS recommends each apprentice does at least 5–10 hours of supervised grinding work before being signed off, with progressive sign-off on cut-off, grinding, flap disc, and concrete cutting tasks separately. People Also Ask — Grinding Wheel Safety Q: What is the ring test and why is it mandatory before mounting a grinding wheel? The ring test involves gently tapping the wheel with a non-metallic mallet and listening for a clear ring. A dull thud indicates a crack — a cracked wheel must never be mounted. Centrifugal force can cause a cracked wheel to disintegrate at operating speed. Q: Why must the wheel's maximum rated RPM match or exceed the grinder's RPM? If a wheel's maximum RPM is lower than the grinder's operating speed, centrifugal force at speed exceeds what the wheel's bond is designed to withstand and can cause the wheel to burst — projecting fragments at very high velocity. Always check and match RPM ratings. Q: What is kickback and how is it prevented during grinding? Kickback occurs when the wheel catches in the cut and the grinder is violently thrown back toward the operator. It is prevented by maintaining a firm two-hand grip, keeping the angle correct for the application, using the guard, and never using the side of a cut-off disc for grinding. Q: Why must the angle grinder guard never be removed? The guard deflects wheel fragments away from the operator if a wheel disintegrates, and directs sparks away from the face. Removing it is a breach of safe work practice and violates the AS 1788.2 framework for abrasive wheel use. Many serious injuries are caused by unguarded grinders. Q: What PPE is required when using angle grinders and cutting discs? A full face shield worn over safety glasses, hearing protection, leather or cut-resistant gloves, and clothing that covers exposed skin to protect against sparks and fragments. When cutting masonry, concrete, or stone, a P2 dust mask or respirator is required for silica dust.