An angle grinder cuts, grinds, polishes, cleans, and sharpens metal, masonry, and wood when paired with the right disc and safe technique.
What an angle grinder does in plain terms
An angle grinder is a handheld power tool that spins a disc at high speed. Swap the disc and you change the job. With a thin wheel it slices steel bar. With a grinding wheel it knocks down welds and bevels edges. Fit a flap disc and you can smooth metal to a paint-ready sheen. A diamond blade turns it into a tile or masonry cutter. Add a wire cup and rust comes off fast. It even shapes wood when used with the right carving disc and a light touch.
The core idea stays the same. The motor spins. The guard shields you. Your hands guide the tool along a marked line, a weld bead, or a rusty patch. Let the disc do the work and keep the edge square to the task. Small moves beat force every time.
Core angle grinder jobs and the right disc
| Job | Best disc or wheel | Why it works |
|---|---|---|
| Cut steel bar, bolts, sheet | Type 1/41 cut-off wheel | Thin kerf runs cool and tracks straight |
| Trim stainless or alloy | Inox cut-off wheel | Sulfur-free bond protects the finish |
| Grind welds, bevel edges | Type 27 grinding wheel | Hard bond removes metal fast with control |
| Smooth metal for paint | Flap disc (40–80 grit) | Conforms to curves and leaves a clean scratch |
| Remove rust or paint | Wire cup or wire wheel | Clears flakes without heavy stock removal |
| Cut tile or pavers | Diamond blade (continuous rim) | Cleans cuts with less chipping |
| Score and break concrete | Diamond blade (segmented) | Gaps cool the rim during long cuts |
| Tuckpoint mortar | Tuckpoint blade set | Matched width clears joints cleanly |
| Polish stainless | Non-woven surface conditioning disc | Blends scratches for a brushed look |
| Sharpen mower blades | Grinding wheel or flap disc | Forms a crisp bevel with control |
| Shape hardwood | Carving disc with limiters | Teeth with guards reduce bite and kick |
| Clean mill scale | Flap disc (60–80 grit) | Removes oxide while keeping flat |
Safety rules you never skip
Two things keep you safe: the guard and the match between wheel and speed. The guard must stay on and set to block sparks. The wheel must be rated higher than the tool’s no-load RPM. That is not a guess. See the U.S. rules for abrasive wheels in the OSHA 1910.215 standard. If you work in the UK, the HSE guide to abrasive wheels in HSG17 gives clear practice for mounting, guards, and training.
Wear eye and face protection, hearing protection, gloves that grip, long sleeves, and leather shoes. Clamp the work. Keep bystanders out of the spark path. Check the disc for chips and a cracked sound. Spin up in free air before each cut. Let the wheel stop before you set the tool down. These habits prevent most mishaps.
One more rule: line up the flange, blotter, and arrow marks when you mount a wheel. Tighten by hand with the wrench, not a pipe. Replace wheels that wobble. A steady wheel cuts straight and holds size.
Angle grinder uses and applications across materials
Metal work tops the list. You can lop off a bolt that fused to a nut. You can trim rebar flush with a slab. You can grind a bevel on plate for a full-penetration weld. After welding, you can blend the bead to a smooth seam that vanishes under paint. Switch to a flap disc and the scratch pattern fades to a satin finish.
In masonry, a diamond blade scores a control joint, notches a block, or cuts tile to fit around a valve. Keep dust down with a shroud and a vac. Make a shallow pass, then deepen the cut. That keeps the rim cool and the line true.
On wood, a carving disc scoops and rounds. Think bowls, seats, or live-edge slabs. Keep the cut light and keep both hands on the tool. Sanding discs also fit, though a random-orbit sander leaves a finer finish.
Prep work is where the grinder shines. Mill scale, spatter, and old paint come off fast. A wire cup cleans threads and corners that a scraper misses. The tool reaches into tight spots, so you can get to clean metal before primer or weld.
What you use an angle grinder for at home and on site
Home shops use a 4-1/2 inch model for most cuts and clean-ups. It is light, common, and fits many discs. Job sites add 5 inch and 6 inch tools for deeper cuts and faster removal. The bigger tools carry more torque and hold speed under load.
Use cut-off wheels for fast, straight cuts on stock up to their rated depth. Use grinding wheels to knock down high spots and shape edges. Use flap discs when you want a smooth finish without deep scratches. Use diamond blades on tile, stone, and concrete. Use wire cups for rust and scale. Each setup has a clear role.
Angle grinders also stand in for bench tools in a pinch. With a jig you can dress a chisel or a mower blade. With a guide you can cut tile on a balcony where a saw will not fit. With a dust shroud you can chase a crack for epoxy repair. It is a flexible kit in one body.
Technique that makes cuts clean
Grip and stance
Stand off to the side of the wheel, not in line with it. Keep two hands on the tool. Use the side handle. Plant your feet and lock your elbows. A steady stance keeps the wheel square and the cut smooth.
Wheel angle and pressure
For grinding, hold a 10–15° tilt so the outer edge contacts the work. For cut-off, run the wheel square to the line and let it draw a thin spark stream. Feed with light pressure. If the motor bogs, back off and let speed recover.
Start, path, and exit
Score a shallow line first. Then open the cut with short strokes. Keep the line just in view under the guard. Near the end, ease up so the last web does not snap. Brace both sides of the cut to avoid pinch and kick.
Heat and burr control
Heat builds fast in thin stock. Pause to cool the part. On steel, a quick dip in water helps. After a cut, a light pass with a flap disc breaks the burr and saves a cut finger later.
Picking the right size, disc, and power
Tool size and depth
Common sizes are 4-1/2 inch, 5 inch, and 6 inch. A 4-1/2 inch grinder cuts near 1-1/4 inches deep. A 5 inch model reaches about 1-3/8 inches. A 6 inch model nears 2 inches. Pick the smallest tool that reaches the cut while staying easy to hold for the time you need.
Motor type
Brushless motors run cool and hold speed. Brushed tools cost less and still cut well with care. Either way, match the disc RPM rating to the tool’s top speed. The label on the disc shows this rating.
Disc bonds and grits
Hard bonds suit soft metal. Soft bonds suit hard metal. For flap discs, 40 grit eats welds; 60 or 80 grit prepares for primer; 120 grit blends stainless. Inox wheels protect stainless from brown streaks. Diamond blades come in continuous rim for tile and segmented for concrete and block.
Guards, flanges, and blotters
Keep the guard matched to the wheel type. Flat wheels need full rim guard. Depressed center wheels need side guard. Match flange sizes to the wheel and keep blotters in place to spread load. The OSHA grinder checklist at osha.gov is a handy reference for setup checks.
Troubleshooting angle grinder results
| Symptom | Likely cause | Fix |
|---|---|---|
| Wheel binds or kicks | Cut closed and pinched the kerf | Brace both sides; widen the first pass |
| Cut wanders | Too much pressure or flex | Score first; lighten feed; use a stiffer wheel |
| Blue edge on steel | Heat from heavy feed | Back off; use fresh wheel; cool between passes |
| Rapid wheel wear | Wrong bond for the metal | Switch bond; let the wheel self-sharpen |
| Rough finish | Grit too coarse | Step down to a finer flap disc |
| Vibration at speed | Damaged or off-center wheel | Replace wheel; check flanges and blotters |
| Excess sparks | Edge too steep on grinding | Set 10–15° tilt; lighten the pass |
| Tile chips | Segmented blade on glaze | Use a continuous rim and a slow feed |
| Dust clouds | No shroud or vac | Fit a shroud and connect a class M vac |
| Stainless discoloration | Wheel with iron or sulfur | Use Inox wheels and clean pads |
Using an angle grinder for cutting and grinding on real projects
Gate repair in steel
Cut the rusted hinge bolts with a 1 mm cut-off wheel. Grind the weld area clean to bright metal. Fit the new hinge, tack it, and check swing. Weld in short runs, then blend the bead with a 60 grit flap disc. A quick wipe with solvent and the steel is ready for primer.
Tile trim around pipes
Mark the center, then plunge a diamond blade to form a cross. Nibble the corners until the round fits the pipe escutcheon. A light rub with a diamond hand pad smooths the edge.
Deck screws and flush cuts
When a screw strips and sits proud, score a tight circle with a thin wheel and pop the head. Pull the board, grab the stub with pliers, and remove it clean.
Mower blade tune-up
Clamp the blade. Grind the bevel to match the factory angle. Keep strokes even so the edge stays straight. Balance the blade on a nail. If one side drops, take a touch off the heavy end. A balanced blade runs smooth and keeps bearings happy.
Care that keeps the grinder ready
Blow dust out of the vents. Check the cord or battery pack for wear. Spin the guard collar and clean out grit so it moves freely. Replace the backing flange if it grooves. Keep a spare side handle in the case. Small parts keep the tool safe and easy to run.
Store wheels flat in a dry spot. Do not stack heavy items on them. Mark the date on each pack and rotate stock. Before mounting, tap a vitrified wheel and listen for a clear ring. A dull thud means damage and that wheel goes in the bin. The HSE notes the need for sound storage and mounting practice in HSG17, which pairs well with the OSHA rules linked earlier.
Noise, dust, and vibration control
Use a vac and shroud for concrete and mortar. Wet cutting also works on tile and stone in open areas. Pick low-vibration wheels where possible and keep your grip light. Take breaks on long jobs. Your hands and ears will thank you.
Route the cord over your shoulder so it stays off the wheel. On battery tools, keep packs cool and swap before they sag. Good control starts with a tool that runs smooth and steady.
Mind the spark path. Aim sparks at a clear, fire-safe zone, never toward fuel cans, solvents, or glass. Keep a fire extinguisher nearby when cutting or grinding indoors. After hot work, do a watch for smoldering dust or chips. A five minute pause saves headaches. On site, cordon off the work area so others do not walk through the sparks.
Quick start routine for clean, safe work
1) Plan
Pick the disc for the material. Mark the line. Clamp the work. Clear the area.
2) Prep
Check the wheel and guard. Set the guard to block sparks. Fit PPE and connect dust control if needed.
3) Cut or grind
Score first. Keep a steady feed. Watch the spark stream and adjust pressure to hold speed.
4) Finish
Deburr with a flap disc. Wipe the part clean. Let the wheel stop before you set the tool down. Put the grinder back in the case with the cord coiled loose.