Rotary File Ball: Head diameter: 40 mm, Handle length: 68 mm, Handle outer diameter: 25 mm Durable: The grinding head is made of thermally treated tungsten carbide, with a service life ten times longer than high-speed steel. It is suitable for processing various types of metal materials, including hardened steel (≤HRC65). Multipurpose: Grinding accessories are widely used for engraving, bowl cutting, model making, wood carving, bowl chiseling, shaping, deburring, grinding, etc. Function: The engraving wheel has a very rough coating that quickly eliminates voids while maintaining a relatively smooth surface.