Check the listing for details. Abrasive Conical Mounted Stone Grinding Bits 1/4" Shank 0.79" Diameter 5pcs. Condition: New. Listed at 16.22 USD. Descriptions:This corundum grinding bit has high hardness and is suitable for metal grinding, especially for steel parts after heat treatment.White corundum has a higher hardness than brown corundum. The particle size is easily broken, the edges and corners are sharp, good self-sharpening, strong grinding force, high efficiency, and high temperature resistance.Suitable for grinding of hardened steel, high carbon steel, general high speed steel, alloy steel, etc. cutting tools and workpieces, precision grinding of measuring tools and instrument parts, and also suitable for form grinding.Can be installed on electric tools such as electric grinders, it has good wear resistance and sanding performance.Tips:The new corundum grinding bit should be tried at a low speed before use. If there is a jumping problem, do not continue to use it.