Answer
Jul 15, 2024 - 06:07 PM
The numbers on sandpaper indicate the grit, with a lower grit number means coarser grit for more aggressive material removal, while a higher number signifies finer grit for smoother finishes. Technically, the grit number refers to the number of abrasive particles that can fit through a 1 inch square filter with holes in it. For example, a 40 grit sandpaper has particles that fit through a filter with approximately 40 holes per square inch. A 400 grit sandpaper has particles that fit through a filter with approximately 400 holes per square inch so the particles will be much smaller when compared to the 40 grit.