Rotary File, 1" x 5/8" x 1/4" Bulb Shaped, Carded  :  1" x 5/8" Bulb Shaped Mounted Rotary File with 1/4" Shank, Bulk Max RPM: 2,500. Shank mounted rotary files are tough, rugged tools made from special tempered steel. Rotary files have specially hardened cutting edges and can be used on steel, bronze, fiberglass, plastic and many other materials.