The right abrasive cuts faster, lasts longer and is safer to use. The wrong one wears out in minutes — or worse. Here's how to choose between cutting discs, grinding wheels and flap discs, and use them properly.
Cutting discs — thin and for slicing only
Thin cutting (slitting) discs are made to cut through metal with the edge of the disc. Common sizes are 115mm and 125mm for angle grinders; 1mm and 1.6mm thicknesses cut fast and clean.
- Never grind with a cutting disc. Side pressure on a thin disc can shatter it — that's the single most important rule of abrasives.
- Match the disc bore and diameter to your grinder, and never exceed the disc's marked maximum RPM.
- Let the disc do the work — light, steady pressure cuts better and lasts longer than forcing it.
Grinding wheels — for removing metal
Grinding wheels (usually 6mm+ thick, with a depressed centre) are built for grinding with the face of the disc — dressing welds, removing material and chamfering edges. They're tough but slow compared with a flap disc, and leave a coarser finish.
Flap discs — grind and finish in one
A flap disc is overlapping abrasive flaps that grind and blend at the same time, leaving a smoother finish than a grinding wheel and lasting far longer than sheet abrasives. They're the go-to for weld dressing and surface finishing.
- Lower grit (40–60) removes metal fast; higher grit (80–120) blends and finishes.
- Work the disc at a shallow angle for the best balance of cut rate and disc life.
Match the abrasive to the metal
This matters more than people think. For stainless steel, use discs marked INOX / iron-free — ordinary discs can leave iron contamination that rusts and discolours the stainless. For aluminium, use discs designed for non-ferrous metals to avoid clogging ("loading"). For mild steel, standard discs are fine.
Safety first, every time: always use the grinder guard and eye and face protection; inspect each disc for chips or cracks before fitting; check the expiry date; and let a new disc spin up to speed clear of the work before you start the cut. Store discs flat and dry — there's more in our care & storage guide.
Quick reference
- Cutting through metal: thin cutting disc (1–1.6mm). Edge only — never grind.
- Heavy metal removal: grinding wheel.
- Weld dressing & finishing: flap disc (grit to suit).
- Stainless: INOX/iron-free discs. Aluminium: non-ferrous discs.
Not sure which to grab? Tell us the metal and the job and we'll set you up with the right discs — and the spares to keep going.
More reading: welding PPE & safety essentials and choosing a welding process.