A high quality industrial abrasive made for extended general purpose grinding on metals, castings, welded joints, rivets and rust or for working with conical surfaces. Do not run in excess of 30,000 RPM. Aluminum Oxide Grinding Stone Dremel 8193 Aluminum Oxide Grinding Stone, 5/8DIA: Ideal for sharpening, deburring and general purpose grinding Cylindrical shaped Dremel stone Made from aluminum oxide no. 8215 Shank diameter - 1/8" Bit diameter - 5/8" 5/8" diameter grinding stone Works on most materials including stainless steel Special Features aluminum oxide grinding stone