Types: twist drills, center drills, spotting drills, step drills, taper shank drills, drill bit with coolant holes Types: ... twist drill bit, center drill bit, spotting drill bit, step drills, taper shank drills, and drill bit with coolant holesSize ... : carbon steel, alloy steel, cast steel, tooling steel, mold steel, aluminum alloy steel, and non ferrous alloyWe also can produce special ...