Forney 60073 Mounted File, Cylindrical Shaped with 1/4-Inch Shank, 1-Inch-by-1/2-Inch Shank mounted rasps are tough, rugged tools made from special tempered steel They are the perfect product to remove material in hard to reach places Ideal for powered hand drills Rotary files have specially hardened cutting edges perfect for steel, bronze, fiberglass, plastic and many other materials Max RPM is 2,500