Turn your Dremel rotary tool into a simple-to-use rotary grinder with the Aluminum Oxide Grinding Stone. Ideal for sharpening, deburring and grinding on most materials. The versatile 5/8 In. (15.9 mm) diameter Aluminum Oxide Grinding Stone works well for extended general purpose grinding on metals, sharpening tools, castings, welded joints, rivets and rust removal. The 971 Grinding Stone features a convex disc shape; however, Dremel offers a variety of grinding stones with different bit shapes to support virtually every possible grinding application.