If you could only add one tool to your shop, an angle grinder would make a strong argument for the slot. A 4.5” or 5” angle grinder with the right disc can cut metal, tile, concrete, and stone; grind welds flat; remove rust; sharpen blades; strip paint; and polish metal surfaces. Here’s a practical breakdown of what angle grinders can do and which discs you need for each job.
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The tool itself
Angle grinders come in 4.5”, 5”, 6”, and 7” disc sizes. For most DIY and light professional work, 4.5” is the standard — discs are cheaper, more varied, and the tool is lighter. A 5” or 7” grinder is better for sustained heavy metal cutting or large stone work.
Corded vs. cordless: A corded grinder (4-13 amps) gives you unlimited runtime and consistent power. Cordless grinders (18V or 20V platforms) have caught up in recent years and are genuinely useful for work away from outlets, but they’re heavier and a fresh-cut disc on thick steel will drain a battery fast. For shop work: corded. For site work or trim-out: cordless is viable.
Key specs to look for:
- RPM: 10,000-12,000 for 4.5” (match disc RPM rating)
- Amp draw: 6+ amps for general use, 9-11 for heavy metal cutting
- Spindle lock and guard: not optional — use them
- Paddle switch vs. side switch: paddle (requires constant pressure) is safer; releases if you drop it
What you can do with it
1. Cut metal
The most common use. A metal cut-off wheel (thin, ~1/16” thick) cuts rebar, angle iron, bolts, pipe, sheet metal, and structural steel. This is faster than a hacksaw by an order of magnitude and more maneuverable than a cold cut saw in tight spots. You can notch, trim, and cut to length.
Disc to use: Aluminum oxide cut-off wheel (type 1 or type 41), rated for the tool’s RPM.
2. Grind welds
After welding, welds need to be ground flush — either for aesthetics or before painting. A grinding disc removes the excess weld material quickly. Start with a grinding disc (1/4” thick, aggressive) and finish with a flap disc for a smoother surface.
Disc to use: Aluminum oxide grinding disc (type 27), then 40-60 grit flap disc.
3. Remove rust
A wire wheel or wire cup brush on an angle grinder removes surface rust, mill scale, and old paint faster than anything except a needle scaler. Works on steel, iron, and cast iron. Prep bare metal for paint, primer, or weld.
Disc to use: Knotted wire wheel or wire cup brush. Wear face shield, not just glasses — wires break off at high speed.
4. Cut tile and stone
A diamond blade on an angle grinder cuts ceramic tile, porcelain, stone, brick, and concrete block. Great for cuts that don’t warrant a wet tile saw: notching around outlets, trimming field tile that doesn’t fit, cutting pavers. The cut is dry and dusty — mask up and work outside or with ventilation.
Disc to use: Continuous-rim diamond blade for tile; segmented diamond blade for concrete/brick/stone.
5. Cut concrete
Cutting expansion joints, removing concrete, cutting pavers and CMU block. A segmented diamond blade handles this. Multiple passes for deeper cuts. Generates significant silica dust — N95 minimum, P100 respirator is better.
Disc to use: Segmented diamond blade rated for angle grinders.
6. Sharpen tools
An angle grinder sharpens axes, hatchets, lawnmower blades, shovels, hoes, and mattocks quickly. Not for chisels or plane blades (too aggressive, generates too much heat), but for garden tools and coarse-edge equipment it’s ideal. One pass with a grinding disc or sharpening stone accessory restores a working edge in under a minute.
Disc to use: Grinding disc or dedicated sharpening stone attachment.
7. Strip paint
A flap disc or paint stripping disc removes old paint and primer from metal surfaces. Faster than chemical strippers for large areas, less toxic if you’re working outdoors. Also useful for stripping painted concrete or removing old mastics and adhesives.
Disc to use: 40-grit flap disc for aggressive removal; paint stripping disc (nylon abrasive mesh) for lighter work.
8. Smooth metal surfaces
After grinding or cutting, a flap disc leaves a much cleaner surface than a grinding wheel. Step down through grits: 40 → 60 → 80 → 120 for a progressively smoother finish. Essential if you’re painting, powder coating, or want a clean appearance on exposed steel.
Disc to use: Aluminum oxide or zirconia flap disc, progressively finer grits.
9. Cut rebar
Before pouring concrete, rebar typically needs to be cut to length. An angle grinder with a cut-off wheel handles rebar up to #5 (5/8”) quickly. For #6 and larger, a chop saw or reciprocating saw with a metal blade is more practical.
Disc to use: Metal cut-off wheel.
10. Mortar removal and tuckpointing
A tuckpointing blade (two-diamond-blade setup with a gap between) removes deteriorated mortar from brick joints before repointing. An angle grinder makes this work feasible for a DIYer. More controlled than a cold chisel.
Disc to use: Tuckpointing blade specifically designed for mortar joints.
11. Polish metal
With a polishing pad and compound, an angle grinder can buff and polish steel, stainless, and aluminum to a high shine. Useful for restoration work, fabrication finishing, and metal art.
Disc to use: Felt polishing pad with polishing compound, or flap discs progressing through 120-400 grit.
12. Cut fiberglass and composites
A metal cut-off wheel or diamond blade cuts fiberglass panels, carbon fiber, and other composites. Works for boat work, bodywork, and custom fabrication. Use a thin wheel and wear respiratory protection — fiberglass and carbon fiber dust is a serious lung hazard.
Disc to use: Metal cut-off wheel or fine-tooth diamond blade.
Safety: what actually matters
An angle grinder spins at 10,000+ RPM. A disc that shatters or kicks back will cause serious injury. The rules aren’t optional:
- Never remove the guard. The guard is there for disc failures and kickback, not just to be in the way. If a disc position requires removing the guard, use a different tool.
- Match disc RPM to tool RPM. A disc rated for 10,000 RPM shouldn’t run on a tool doing 12,000 RPM. RPM rating is printed on the disc.
- Inspect discs before use. A cracked or chipped disc should be discarded. Grinding discs can shatter with no warning.
- Clamp your workpiece. Trying to hold work in place with your hand while using an angle grinder causes kickback and contact injuries.
- Use full face protection. Safety glasses alone are insufficient for angle grinder work. A face shield over safety glasses is the minimum for cutting and grinding.
- Two-handed grip, correct stance. Both hands on the tool. Position yourself to the side of the disc rotation plane, not directly behind the disc.
What an angle grinder is not for
- Cutting wood. Never use a grinding disc or cut-off wheel on wood. Friction can cause fire, and kickback behavior is unpredictable. Use a circular saw.
- Fine finishing work. For chisels, plane blades, and precision edge tools, use a bench grinder or wet sharpener. The angle grinder is too aggressive and fast.
- Precise cuts. For cuts that need to be accurate to 1/32”, use a miter saw, table saw, or cold cut saw. The angle grinder is a roughing-in and metalwork tool.
A note on disc compatibility
Not all discs fit all grinders. The mounting thread (5/8”-11 for most U.S. grinders), disc diameter, and arbor hole size all need to match. Always buy discs rated at or above your tool’s RPM. The disc is the expendable part — buy quality discs from recognized brands (Norton, Weiler, Dewalt, Bosch, Metabo) rather than no-name multi-packs.