A disc rated for mild steel will work on stainless. It'll also load up with material, overheat the edge, and leave discolouration you'll be grinding out twice. The fix is a five-minute check before you cut.
Start with the bond, not the grit
Stainless needs a disc bonded specifically for it — usually marked INOX on the label. INOX discs run cooler and shed swarf faster, which matters more on stainless than grit size does. A standard disc at the right grit will still overheat the weld.
Overheating stainless doesn't just slow you down — it changes the metal's corrosion resistance at the cut line.
Match RPM to the disc, every time
Every disc carries a maximum RPM printed on the label. Grinders vary — a cheap angle grinder and a premium one won't spin the same disc at the same rate. Check both numbers before you start, not just the disc's rating alone.
Once you've matched bond and RPM, grit is the easy part:
- 60 grit — stock removal
- 120 grit — finishing
- 240 grit — prepping for polish