Roxon 28778 aluminum-oxide mounted inverted cone-shaped points have a 9/32 inch diameter head with 3/32 inch steel shank. Tip is made from high quality aluminum oxide materials of consistent hardness. Use on especially hard materials such as cast iron, unhardened steels, non-ferrous metals, hard metal alloys, welded joints, rivets and rust. Ideal for sharpening, debarring and general purpose grinding.