CPC Subgroup
G11B 3/56 Sharpening (grinding B24B3/00, B24B19/00)
Full Title
Recording by mechanical cutting, deforming or pressing, e.g. of grooves or pits; Reproducing by mechanical sensing; Record carriers therefor (G11B11/00, take precedence) > Styli, e.g. sapphire, diamond > Sharpening (grinding B24B3/00, B24B19/00)