A 1 mm (0.04 in) disc cuts fast and generates little heat, which matters on thin wall and on stainless where discolouration follows heat. It is also fragile and wears quickly on heavy section.
A 2.5 or 3 mm (0.12 in) disc lasts far longer in thick material and tolerates a less-than-perfectly-straight cut. Thin discs are the default for tube and sheet; thick discs for bar and plate.
The questions welders ask
Can I use a cutting disc for light grinding?
No. Cutting discs are made to work on their edge and can shatter if loaded on the face. That is one of the few unambiguous rules in abrasive use, and the reason grinding discs are much thicker.
Last reviewed 2026-08-14