An angle grinder is a handheld power tool that uses a rotating abrasive or diamond disc to cut, grind, sand, or clean metal, stone, concrete, and masonry. It is one of the most versatile — and most hazardous — tools on any worksite. Choosing the right size, fitting the correct disc, and using proper technique are not optional extras; they are the difference between a controlled cut and a serious injury.

This guide covers grinder sizes from 115 mm to 230 mm, every major disc and attachment type, how to select the right grinder for the job, step-by-step operating technique, kickback prevention, and Australian PPE requirements.

Browse AIMS Industrial’s angle grinder range →

What Is an Angle Grinder?

An angle grinder (also called a side grinder or disc grinder) is a power tool in which an electric, battery, or pneumatic motor drives a spindle at high speed. The spindle sits at a right angle to the motor body — hence the name. A threaded spindle accepts a wide range of discs, wheels, and attachments secured by a clamping flange and lock nut.

Angle grinders are used across fabrication, construction, automotive, mining, and maintenance work. Common applications include cutting steel bar and sheet, grinding weld seams, removing rust and paint, cutting concrete and tile, and polishing metal surfaces.

How an Angle Grinder Works

The motor drives a pair of bevel gears that transfer power from the motor axis to the spindle axis at 90°. This gear set also steps down the motor’s high RPM to the rated no-load spindle speed, which varies from roughly 13,300 RPM on a 115 mm grinder to 6,650 RPM on a 230 mm machine. Abrasive disc standards specify a maximum surface speed of 80 m/s; the different RPM ratings for each disc diameter are calculated from this limit. A wheel guard covers the upper half of the disc and must remain in place during operation — removing it is illegal under Australian workplace health and safety law.

Angle Grinder vs Bench Grinder vs Die Grinder

Angle Grinder Sizes — 115 mm to 230 mm

Angle grinder size refers to the maximum disc diameter the tool accepts. A larger disc means more cutting depth and surface coverage, but also more weight, greater stored energy, and a higher consequence if something goes wrong. The rule is simple: choose the smallest disc that comfortably completes the job.

115 mm (4½ inch) Angle Grinder

The 115 mm grinder is the most compact and lightest in the range, typically weighing 1.6–2.0 kg. Maximum no-load speed is around 13,300 RPM (calculated at the 80 m/s disc speed limit). Cutting depth is limited to roughly 25 mm in mild steel, making it best suited to light metalwork, bodywork, and tasks in confined spaces where a larger machine won’t fit. Disc choice is narrower than for 125 mm, though the two sizes share many accessories. The 115 mm is also the easiest grinder to control, which makes it a good choice for operators who are less experienced with the tool.

125 mm (5 inch) Angle Grinder

The 125 mm is the industry standard for tradespeople across Australia. Maximum no-load speed is approximately 12,250 RPM. It offers around 30 mm of cutting depth, the widest range of compatible discs and attachments available, and an excellent balance between performance and manageability. The vast majority of cutting wheels, grinding discs, and flap discs sold in Australia are in 125 mm format. If you are buying one grinder for general trade use, 125 mm is the answer.

180 mm (7 inch) Angle Grinder

The 180 mm sits between the compact 125 mm format and the large 230 mm machine, with a maximum no-load speed of approximately 8,500 RPM. It is less common than the two most popular sizes and is used primarily for heavier steel fabrication and large-area grinding tasks where a 125 mm disc is too slow but a 230 mm machine is prohibited by site policy. Weight is typically 4.0–5.0 kg. Disc selection is narrower than for 125 mm or 230 mm.

230 mm (9 inch) Angle Grinder

The 230 mm is the largest common angle grinder size, with a maximum no-load speed of approximately 6,650 RPM. It provides cutting depth of up to 65 mm and is used for heavy structural steel, concrete cutting, and large-area surface grinding. These machines typically weigh 5.0–6.5 kg and require considerably more operator strength and attention than smaller grinders. Their mass and stored energy mean a disc burst or kickback event carries a significantly higher consequence. Many Australian worksites prohibit 230 mm grinders entirely — check site-specific SWMS requirements before bringing one to site.

Are 9-Inch Angle Grinders Banned in Australia?

230 mm angle grinders are not banned by national legislation in Australia. However, they are the subject of specific hazard alerts from multiple state safety regulators, and many companies, industries, and individual worksites have banned or restricted their use through internal policy.

SafeWork NSW, SafeWork SA, the Queensland Office of Industrial Relations, WorkSafe WA, and NT WorkSafe have all issued angle grinder safety alerts specifically referencing 230 mm machines following fatalities. The combination of high stored energy in the spinning disc, a no-load speed of 6,650 RPM, and the tool’s substantial mass means a burst or severe kickback event can be fatal. The disc’s kinetic energy at operating speed is orders of magnitude greater than for a 125 mm machine running comparable work.

Where a site or employer has banned 230 mm grinders, that ban is legally enforceable under the Work Health and Safety Act 2011 (Cth) or its state and territory equivalents. Workers are required to comply regardless of whether a national prohibition exists. If your site or SWMS restricts 230 mm grinders, use a 125 mm machine instead.

Types of Angle Grinder

Corded (Electric) Angle Grinder

Corded grinders run on 240 V single-phase power and are the standard for workshop and site use where power access is available. They deliver consistent power output regardless of a battery’s state of charge, making them better suited to sustained heavy grinding over extended periods. Rated power typically ranges from 700 W (115 mm light duty) to 2,400 W (230 mm heavy duty). Weight tends to be lower for a given power output than cordless equivalents because there is no battery pack.

Key features to look for on a corded grinder: soft-start (reduces startup torque shock on the disc and operator), electronic speed control (maintains speed under load to prevent bogging), anti-restart (prevents the grinder restarting automatically after a power interruption — required in many workplace policies), and an auto-stop brake (stops the disc quickly when the switch is released).

Cordless (Battery) Angle Grinder

Cordless grinders run on 18 V, 36 V, or dual-18 V (nominally 36 V) battery platforms. For 125 mm cutting and grinding, 36 V or dual-18 V is the practical choice — a single 18 V battery bogs under sustained load with larger discs. Battery capacity matters: 5.0 Ah is a practical minimum for productive cutting work; 6.0 Ah or higher is recommended for sustained grinding. Modern brushless-motor cordless grinders rival corded models for short-duration cutting tasks.

Cordless grinders are ideal for site work, locations without convenient power access, and jobs requiring freedom of movement around large structures. The trade-offs are weight (battery packs add 600 g–1.0 kg) and the need to manage battery charge across a working day. Keeping a second battery charged and on hand is standard practice on productive sites.

Pneumatic (Air-Powered) Angle Grinder

Pneumatic grinders are driven by compressed air, typically at 90 PSI / 6.2 bar with a flow requirement of 300–400 L/min depending on the tool’s rated consumption. They are lighter than corded or cordless equivalents for the same power output and have no motor windings to overheat during sustained use, making them the preferred choice in automotive, manufacturing, foundry, and shipyard environments where compressed air is already plumbed throughout the facility.

Air grinders deliver excellent power-to-weight ratios and tolerate dusty, wet, and high-temperature environments better than electric tools. The practical limitation is the air supply — the grinder must be within hose reach of the compressor, and the compressor must produce sufficient volume to sustain the tool at rated speed. A compressor that is undersized for the grinder’s flow requirement will cause the tool to lose speed under load.

Angle Grinder Discs and Attachments

The disc or attachment determines what an angle grinder can do. Fitting the wrong disc for the material or task is one of the most common causes of angle grinder accidents. Always verify that the disc’s rated maximum RPM meets or exceeds the grinder’s no-load speed before fitting. Never fit a disc rated for a smaller, slower grinder to a larger, faster machine.

See the AIMS cutting disc guide for detailed disc selection by material and application. For metal cutting where a cutting disc is too slow for the material thickness, or where complex profiles, stainless steel, and aluminium need to be cut efficiently, see the AIMS plasma cutter guide.

When hot-work restrictions, confined spaces, or the need for a quieter, spark-free cut rule out a cutting disc, a hacksaw is often the right tool. See the AIMS Hacksaw Blade Guide to match blade TPI and tooth type to your material.

Cutting Wheels

Cutting wheels (also called cut-off wheels) are thin — typically 1.0–1.6 mm for metal and 2.5–3.0 mm for masonry — and are designed for plunge and traverse cutting only. They must not be used for side grinding or any form of lateral pressure. Side loading on a thin cutting wheel dramatically increases the risk of a burst. Type 41 wheels are flat across the face; Type 42 wheels have a depressed centre that allows the clamping nut to sit below the cutting plane, providing a small increase in cutting depth.

Cutting wheels are available in formulations for mild steel, stainless steel, aluminium, and concrete or masonry (bonded abrasive or diamond-tipped). Always match the wheel to the material being cut. Using a steel wheel on concrete, or a masonry wheel on steel, destroys the disc rapidly and creates a burst risk.

Browse cutting wheels at AIMS Industrial →

Grinding Discs

Grinding discs (Type 27, depressed-centre) are 4–6 mm thick and are designed for surface grinding at an angle of 15–30° to the workpiece. Because of their thickness, they can tolerate the lateral loads involved in grinding work — unlike thin cutting wheels. They remove material aggressively and are the correct tool for weld dressing, cleaning up bevel preparations, removing excess material from fabrications, and general surface conditioning on steel.

Do not use a grinding disc for cutting. The thickness wastes material, and a rotating grinding disc forced into a narrow kerf can bind violently.

See the AIMS grinding disc guide for grit and bond selection by material and application. Browse grinding discs at AIMS Industrial →

Flap Discs

A flap disc consists of overlapping abrasive cloth “flaps” bonded to a fibre or plastic backing plate. As the outer flaps wear, fresh abrasive is progressively exposed, giving a more consistent performance across the disc’s life than a rigid grinding disc. Flap discs are used for blending, finishing, and controlled stock removal on steel, stainless steel, and aluminium. They leave a smoother surface than a grinding disc for the same material removal rate, which reduces the time spent on finishing before coating or inspection.

Type 27 flap discs are flat and used at low angles (10–15°) for flat-surface blending and finishing. Type 29 flap discs are conical and engage at higher angles (15–25°), giving more aggressive stock removal and working well on curved surfaces and in corners. For grit selection: 40–60 grit for heavy blending and weld removal, 80 grit for intermediate work, 120 grit for pre-paint finishing. Zirconia and ceramic abrasive flap discs cut cooler and last significantly longer than aluminium oxide types on steel.

See the AIMS flap disc guide for full grit and abrasive type selection. Browse flap discs at AIMS Industrial →

Wire Brushes and Cup Brushes

Wire brushes and cup brushes remove rust, scale, weld spatter, and loose paint from metal surfaces without removing significant base material. Twist-knot wire brushes are more aggressive and longer-lasting, suited to heavy deposits and tight mill scale. Crimped-wire brushes give a finer finish on lighter contamination and are less likely to leave deep scratch marks on softer substrates. For the full knotted vs crimped decision matrix, cup vs wheel vs end brush geometry, RPM safety limits and the Pferd Combitwist range, see the Wire Brush & Wire Wheel Guide. Cup brushes cover a wider surface area than flat disc brushes and are the practical choice for flat surfaces and the faces of weld seams.

Wire brush work generates wire fragments and particles that travel at high velocity in the direction of rotation. A full face shield — not just safety glasses — is mandatory. Wear long sleeves to protect arms from wire fragments. Check for loose, broken, or protruding wires before each use and discard the brush immediately if any are found.

Stripping and Cleaning Discs

Non-woven abrasive stripping discs (similar in construction to industrial Scotch-Brite pads) remove paint, adhesive residue, and light surface coatings without cutting into the base metal beneath. This makes them the correct choice for surfaces that need coating removal while preserving the substrate — for example, removing underseal from vehicle panels, stripping old paint from fabricated steel prior to re-coating, or cleaning rust bloom from precision surfaces where grinding would alter dimensions.

Stripping discs run at lower cutting rates than bonded abrasive discs and generate less heat, making them safer on thin sheet and tube. Standard PPE requirements apply.

Browse stripping and cleaning discs at AIMS Industrial →

Polishing Pads and Backing Plates

Foam or wool polishing pads, attached via a hook-and-loop or threaded backing plate, turn an angle grinder into a surface polisher. This application strictly requires a variable-speed grinder set to a low speed — typically 3,000–5,000 RPM. Running a polishing pad at full grinding speed burns the paint, destroys the pad, and risks injury. Polishing is generally done with the guard set in a position that suits the work, requiring extra care about body positioning and disc exposure.

How to Choose an Angle Grinder

Five decisions drive the right grinder choice: disc size, power source, rated power, features, and ergonomics.

Disc size: Start with the smallest disc that will comfortably complete the job. For general trade use, 125 mm covers 90% of applications. The 230 mm format is warranted for structural steel fabrication or large concrete work and should only be used by experienced operators with appropriate site approval.

Power source: Corded for sustained heavy use, fixed-location workshop work, or where consistent power delivery is critical. Cordless (36 V) for site mobility and areas without convenient power access. Pneumatic where compressed air is already available and a lightweight sustained-use tool is preferred.

Rated power: For 125 mm, 900–1,200 W covers most applications comfortably. For 230 mm, 2,000–2,400 W is typical. An underpowered grinder bogs under load, increases kickback risk by causing the disc to slow and catch, and reduces disc life through overheating.

Features that matter:

• Anti-kickback brake: Detects sudden disc deceleration (indicating a catch or bind) and cuts motor power. Significantly reduces the severity of kickback events. Recommended for any sustained or overhead application.
• Soft-start: Ramps to operating speed rather than slamming to full RPM on switch activation. Reduces startup torque shock on both the disc and the operator’s wrists.
• Electronic speed control: Actively maintains the set speed under varying load. Prevents bogging in sustained heavy grinding and reduces the risk of disc catch at the moment of breakthrough.
• Anti-restart: Prevents the grinder restarting automatically after a power interruption or accidental switch activation while carrying the tool. Required by many workplace safety policies.
• Paddle switch: Must be actively held for the grinder to run. Safer than a lock-on slide switch for most applications because the tool stops the moment it leaves the operator’s hand.

Ergonomics: If possible, hold the grinder in both hands before purchasing. The auxiliary handle should be positionable for both horizontal and vertical use. Declared vibration levels (in m/s² under the EU Machinery Directive / ISO 20643) are a useful comparator for operators who will use the tool for extended periods — high vibration exposure contributes to hand-arm vibration syndrome (HAVS) over time.

How to Use an Angle Grinder — Technique and Setup

Pre-Use Inspection

Before every use, inspect the disc for cracks, chips, delamination, or any sign of damage. For bonded abrasive grinding wheels, perform the ring test: suspend the wheel on a finger through the arbour hole and tap lightly with a non-metallic implement. A clear ringing tone indicates an intact wheel; a dull thud indicates an internal crack — discard the wheel. Check that the guard is secure, correctly positioned, and oriented to cover the upper half of the disc. Verify the disc’s rated maximum RPM meets or exceeds the grinder’s no-load speed. Confirm the disc is the correct type for the material being worked. Secure the workpiece so it cannot move during cutting or grinding.

Fitting a Disc

Isolate power before changing discs — unplug the cord, or remove the battery. Remove the old disc and clean both flanges; debris trapped between a flange and a disc causes vibration and uneven loading that accelerates disc wear and burst risk. Fit the correct backing flange for the disc type. Place the disc on the spindle, fit the outer clamping flange with the correct face against the disc, and tighten using the pin spanner supplied with the grinder. The disc should be firmly clamped but not over-torqued. If the disc carries a rotation direction arrow, confirm it matches the grinder’s spindle rotation direction (marked on the guard or label).

Working Angles

Correct working angle depends on the task and disc type:

• Cutting with a cutting wheel: Hold the disc at 90° to the workpiece surface (perpendicular). Do not tilt or twist during the cut. The only motion is traverse along the cut line.
• Grinding with a Type 27 grinding disc: 15–30° to the surface. A steeper angle removes material faster; a shallower angle produces a smoother surface. Start at 20–25° and adjust.
• Blending with a Type 27 flap disc: 10–15° for flat surface blending. This angle engages most of the flap surface and gives the smoothest finish.
• Stock removal with a Type 29 flap disc: 15–25° for more aggressive engagement, useful on contoured surfaces and in corners.

Avoiding Kickback

Kickback occurs when the disc catches, binds, or pinches in the workpiece and the grinder is thrown back toward the operator in a sudden, uncontrolled movement. It is the most common cause of serious angle grinder injuries. The following measures reduce kickback risk:

• Keep both hands on the grinder at all times — the dominant hand on the trigger body, the other on the auxiliary handle. A grinder held with one hand cannot be controlled if kickback occurs.
• Position your body to one side of the cutting line rather than directly behind the disc.
• Keep the wheel guard between you and the disc at all times during operation.
• Never twist, lever, or pivot a cutting wheel within the cut. If the cut drifts, stop and restart from the edge — do not steer the disc back onto line.
• Support the workpiece so that both sides of the cut are supported and the kerf does not close and pinch the disc.
• Let the disc’s speed and weight do the cutting; do not force it by applying heavy downward pressure.
• Use a grinder with an electronic anti-kickback brake for sustained, overhead, or high-consequence applications.

What Not to Do

• Never use a cutting wheel for grinding. Side loading on a thin cutting wheel creates a burst risk.
• Never remove the wheel guard for any reason during operation. The guard is the primary barrier between a disc burst and the operator. Its removal is illegal under Australian WHS law.
• Never use a cracked, chipped, delaminated, or expired disc. Bonded abrasive discs carry an expiry date on the label; resin bonds degrade over time even on stored, unused discs. Check and discard as required.
• Never exceed the disc’s rated maximum RPM. Fitting a 125 mm disc rated to 12,250 RPM on a 115 mm machine running at 13,300 RPM overspeeds the disc beyond its design limit.
• Never use a disc designed for a larger, slower machine on a smaller, faster grinder.
• Never use standard metal or masonry abrasive cutting discs on wood.
• Never set the grinder down before the disc has stopped completely. A spinning disc resting against a surface can cause an uncontrolled movement.

Using an Angle Grinder on Concrete and Masonry

Concrete and masonry cutting or surface grinding requires a diamond cup wheel (for surface work) or a diamond-segmented or bonded abrasive masonry cutting disc — see the Diamond Blade Guide for the full segmented vs continuous rim vs turbo selection by material (concrete, masonry, tile, porcelain, asphalt). Wet cutting with continuous water suppression is the preferred method wherever practicable; it eliminates most airborne dust and extends diamond tooling life significantly.

Where dry cutting is unavoidable, respirable crystalline silica (RCS) dust control is not optional. Concrete, sandstone, brick, and mortar all contain silica. Inhalation of RCS causes silicosis — an irreversible, progressive, and potentially fatal lung disease. A P2 particulate respirator (AS/NZS 1716) is the minimum for any dry grinding of concrete or masonry. P3 or powered air-purifying respirators (PAPR) are required for high-exposure tasks. Work outdoors or with forced extraction ventilation. Comply with the SafeWork Australia Managing the Risks of Silica Code of Practice.

For a complete guide to P1/P2/P3 filter classes, respirator types, and AS/NZS 1716 selection — including silica dust protection — see our Respirator & Dust Mask Guide.

PPE for Angle Grinder Work

Angle grinders are high-energy tools. Sparks, swarf, disc fragments, and noise levels well above 85 dB(A) are inherent hazards. The following PPE is required — not optional — for angle grinder operation in Australian workplaces.

For eye and face protection selection guidance, see the AIMS safety glasses guide. For worksite hi-vis clothing requirements and standards, see the AIMS hi-vis vest guide.

Frequently Asked Questions

What is an angle grinder used for?

Angle grinders cut metal bar, sheet, and pipe; grind and dress welds; remove rust, scale, and paint; cut concrete, tile, and masonry; sharpen blades; and polish metal and painted surfaces. The specific task determines which disc or attachment to fit: a cutting wheel for cuts, a grinding disc for weld dressing, a flap disc for blending and finishing, a wire brush for surface cleaning, and a diamond cup wheel for concrete grinding.

Why are 9-inch angle grinders banned in Australia?

230 mm angle grinders are not banned by national legislation, but SafeWork NSW, SafeWork SA, the Queensland Office of Industrial Relations, WorkSafe WA, and NT WorkSafe have all issued hazard alerts following fatalities involving 230 mm machines. Many companies, industries, and worksites have banned or restricted them through internal policy. Where a site ban exists, it is legally enforceable under Australian WHS legislation. The risk comes from the disc’s high stored energy at 6,650 RPM — a burst or severe kickback event at that energy level can be fatal.

Which is better, a 115 mm or 125 mm angle grinder?

For most tradespeople, a 125 mm grinder is the better everyday choice. The larger disc gives more cutting depth and surface coverage with only marginally more weight and a disc speed of 12,250 RPM versus 13,300 RPM for 115 mm. A 115 mm grinder is slightly easier to manoeuvre in very confined spaces. Both sizes share many disc formats. If you are buying one grinder for general trade use, 125 mm is the practical standard.

Can an angle grinder cut through anything?

No. Angle grinders cut materials matched to the disc fitted: a metal cutting wheel cuts metal; a diamond disc cuts concrete and tile; a masonry disc cuts masonry. Using a metal cutting disc on concrete, or a masonry disc on metal, destroys the disc rapidly and creates a burst risk. Angle grinders are not suitable for wood with standard abrasive discs, flexible plastics, or reinforced rubber. Always confirm the disc is rated for the specific material before cutting.

What should you not use an angle grinder for?

Do not use a cutting disc for side grinding, use an angle grinder to cut wood with standard abrasive discs, operate with the guard removed, use cracked or expired discs, try to stop the disc by pressing it against a surface, or use a disc rated for a larger machine on a smaller, faster grinder. Do not attempt to steer a cutting wheel mid-cut by twisting — stop, back out, and re-enter.

Can I use an angle grinder to cut wood?

Not with standard abrasive cutting discs. Specialised wood-cutting discs rated for angle grinder RPM exist, but most Australian safety authorities and worksite policies prohibit their use because the tool’s high speed and lack of riving knife or blade guard make kickback incidents common and severe. A circular saw or jigsaw is the correct tool for wood. If a wood-cutting disc must be used, it requires a disc specifically rated for angle grinder RPM, an experienced operator, and a task-specific risk assessment.

What are the dangers of using an angle grinder?

The primary hazards are disc burst (fragments expelled at high velocity, capable of causing penetrating injuries), kickback (sudden violent tool movement when the disc catches or binds), burns from sparks and hot swarf, noise-induced hearing damage (95–108 dB(A) typical), hand-arm vibration syndrome (HAVS) from sustained use, eye and face injuries, and dust inhalation — particularly respirable crystalline silica from concrete and masonry grinding. Angle grinders account for a disproportionate share of serious tool-related injuries in Australian workplaces.

What PPE do I need when using an angle grinder?

At minimum: a full face shield (AS/NZS 1337.1:2010), hearing protection with SLC80 ≥ 24 (AS/NZS 1270), a P2 respirator (AS/NZS 1716) for grinding or concrete work, heavy leather or impact-resistant gloves (AS 2161.3 / EN 388), and steel-capped safety footwear (AS/NZS 2210.3). Safety glasses alone are insufficient — disc fragments can travel around the lens edge. Long-sleeved clothing protects arms from spark burns and swarf contact.

How do I avoid angle grinder kickback?

Keep both hands on the grinder at all times. Position your body to the side of the cutting line, not directly behind the disc. Keep the guard between you and the disc throughout the operation. Never twist or pivot a cutting wheel within the cut. Support the workpiece so the cut cannot close and pinch the disc. Let the disc’s speed do the cutting; do not force it. Use a grinder with an electronic anti-kickback brake for sustained or high-consequence work.

Do you need training to use an angle grinder?

Australian WHS regulations class angle grinders as high-risk tools. Formal site induction is required in most workplaces, and many sites require a documented competency assessment before unsupervised use. At minimum, every user must read the manufacturer’s manual, comply with the applicable Safe Work Method Statement (SWMS) for the task, and have received a hands-on demonstration from a competent person. Some industries require formal training certificates.

Is a corded or cordless angle grinder better?

Corded grinders deliver consistent power regardless of battery state and are generally lighter for the same wattage output — better for sustained heavy grinding in a fixed location. Cordless grinders (36 V or dual 18 V) provide freedom of movement for site work and remote locations and are capable enough for most cutting and grinding tasks. For sustained heavy grinding over extended periods, corded remains the practical choice. For site mobility or working away from power, modern cordless grinders are highly capable.

What is the difference between a Type 27 and Type 29 disc?

Type 27 is a flat disc designed for surface grinding and blending at low working angles (10–20° to the workpiece). Type 29 has a conical shape that allows more aggressive engagement at higher angles (15–25°), providing faster stock removal and better performance on curved surfaces and contours. Both disc types are common in the flap disc format: Type 27 suits finishing and blending; Type 29 suits faster material removal and contour work.

What grit flap disc should I use for steel?

For heavy stock removal or weld grinding, use 40–60 grit. For intermediate blending, use 80 grit. For a smooth finish prior to painting or coating, use 120 grit. Zirconia and ceramic abrasive flap discs cut cooler, last longer, and maintain consistent performance across the disc’s life better than aluminium oxide types on steel. See the AIMS flap disc guide for full selection guidance.

Can I use an angle grinder to level concrete?

Yes, with a diamond cup wheel — a double-row cup wheel for aggressive levelling and high spot removal, or a single-row or turbo cup wheel for finer surface work. Concrete grinding generates respirable crystalline silica dust. A P2 respirator (AS/NZS 1716) is the minimum. Wet grind where practicable to suppress dust. Work outdoors or with forced extraction ventilation. Comply with the SafeWork Australia Managing the Risks of Silica Code of Practice.

How long do angle grinder discs last?

It depends on disc type, material, and operator technique. Thin metal cutting wheels typically deliver 30–50 cuts in mild steel under normal use before wearing down. Grinding discs and flap discs last considerably longer — often several hours of intermittent work. Diamond cup wheels can last tens of hours with correct use and water suppression. Discard any disc showing cracks, chips, delamination, or glazing regardless of apparent wear, and always check the expiry date on the disc label — bonded abrasive discs degrade over time even when stored unused.