Short answer: Yes, an angle grinder cuts metal: mild steel, stainless, rebar, sheet metal, aluminum, copper and brass. Let the disc cut at full speed with light pressure, keep it square to the work, and never lean on it. Most people burn through discs because they push, and pushing is what makes a wheel shrink, glaze and eventually shatter.
Which wheel is best for cutting metal?
Three kinds of disc end up on grinders in a metal shop, and only two of them are made to cut.
| Disc | How it works | What happens over time | Use it for |
|---|---|---|---|
| Abrasive cut-off wheel | Grinds itself away to cut | Shrinks with every cut, gets slower and more fragile | The odd cut, when price matters more than lifespan |
| Diamond disc | Diamond grit cuts, the steel body stays | Keeps its diameter, so the last cut is as fast as the first | Regular cutting in steel, stainless, aluminum, copper and brass |
| Flap disc | Sands the surface | Wears down layer by layer | Grinding welds and deburring edges, not cutting |
Why do cut-off wheels disappear so fast?
An abrasive cut-off wheel works by sacrificing itself. Every cut grinds away part of the wheel, which is why it starts at 4 inches and ends up the size of a coin. That is normal for abrasives, and it is why a box of them empties so quickly.
There are two problems with that. A shrinking wheel loses cutting speed at the rim, so each cut takes longer than the last. And a thin, worn wheel is fragile: it is the one most likely to come apart under side load. More on that in Why Do Cutting Discs Break?
A diamond disc works differently. The grit cuts, the steel body stays. It keeps its diameter, which means the last cut runs at the same speed as the first. That is what the Indestructible Disc 2.0 is built around: a turbo rim on a diamond steel body, made for steel, aluminum, copper and brass.
How to cut metal with an angle grinder, step by step
- Mark the line. Use a marker or soapstone, thick enough to see through the sparks.
- Clamp the work and support both sides of the cut. A bench vise or two clamps. The offcut should not sag and pinch the disc as it separates.
- Fit the guard and put on your gear. Safety glasses, gloves and ear protection go on before the tool is plugged in.
- Let the disc reach full speed before it touches metal. Starting a cut against the workpiece kicks the tool and stresses the disc.
- Use light pressure and keep the disc square. Your job is to guide, not to press. If the disc is not cutting, the fix is never more force. Cutting discs are strong in the direction they spin and weak sideways, and twisting in the cut is the single most common way to break one.
- Cut in a straight line. If the line needs to curve, make a series of straight relief cuts instead of steering the disc through the arc.
- Give thin material a break. Let the tool stop between cuts on sheet metal. Heat builds fast and warps it.
- Clean up the edge. A fresh cut leaves a sharp burr. Take it off with a file or a flap disc before anyone handles the part.
Does the metal type change anything?
| Metal | What to expect | What to do |
|---|---|---|
| Mild steel and rebar | Straightforward, lots of sparks | Steady pressure, sparks away from you, cut all the way through instead of snapping the last bit off |
| Stainless steel | Cuts hotter and work-hardens if you dwell in one spot | Keep moving. Do not stop halfway and restart in the same groove |
| Aluminum, copper, brass | Soft and gummy, loads up abrasive wheels | Take lighter passes and back out often to clear the cut |
| Sheet metal | Flexes, grabs and warps from heat | Clamp close to the cut line, make short cuts with pauses |
How do you cut stainless steel sheet with an angle grinder?
Stainless sheet combines the two tricky parts of metal cutting: it holds heat and it flexes.
Clamp it tight. Clamp the sheet to the bench right next to the line, or between two boards, so it cannot vibrate.
Tape the line. Masking tape on the visible side protects the finish from stray scratches and gives you a line you can see.
Keep the disc moving. Stainless work-hardens where the disc dwells, and heat tints the surface around the cut. One steady pass along the line beats stopping and starting.
Deburr both sides. Stainless burrs are especially sharp.
Can you cut rebar, aluminum and brass with an angle grinder?
Rebar: yes. Support the bar on both sides of the cut and cut all the way through. Snapping the last bit off leaves a jagged end and can pinch the disc.
Aluminum: yes, but it clogs abrasive wheels quickly. Light passes keep the cut clear, and the Indestructible Disc 2.0 is built for aluminum as well as steel.
Copper and brass: yes. Same approach as aluminum: light pressure, back out now and then, and clamp pipe so it cannot spin.
Why does the disc grab and kick back?
Kickback happens when the disc binds in the cut. Metal closes on the wheel, the wheel stops, and the tool has to go somewhere: usually toward you.
Prevent it by supporting both sides of the cut. When you cut a bar in two, the offcut should not sag and pinch the wheel as it separates. Support it, or let the cut end where the piece can fall free.
Also keep both hands on the tool and stand out of the plane of the disc, not directly behind it.
What does the guard actually do?
If a disc comes apart at 12,000 RPM, the guard decides where the fragments go. It is the difference between a bang and an injury.
Plenty of people take it off because it gets in the way. It takes seconds to fit a quick-lock guard, and there is no cut worth the alternative.
Add safety glasses for the sparks and fragments, cut resistant gloves because a fresh steel edge is a blade, and ear protection because a grinder on steel runs well past 100 dB.
Will this disc fit my grinder?
The Indestructible Disc 2.0 is 4 inch outer diameter with a 5/8 inch arbor hole and 0.04 inch thickness, which is the standard size for common angle grinders. It runs up to 12,225 RPM, so check that your tool does not exceed that. How to check your grinder in ten seconds: Will This Disc Fit My Grinder?
The short version
Light pressure, square to the work, full speed before contact, and both sides of the cut supported. Do that and the disc lasts, the cut stays clean, and nothing comes apart.
Get the disc built for metal: Indestructible Disc 2.0
