DEWALT Aluminum Oxide 3/4" X 1-1/4" Hp Grinding Point. The DEWALT DWA4974 aluminum Oxide 3/4" x 1-1/4" HP grinding point is designed for deburring, shaping and grooving with ferrous metal. It features a high performance aluminum Oxide tip for long life. A 1/4" hex shank allows for easy bit changes.