HSS reduced shank twist drills material:hign speed steel processing:roll forged,edge ground,milled,fully ground HSS ... shank twist drillspoint angle:118°or 135°Material: High speed steelsurface finished:bright, black oxide,tin coated,sand finished ... durability of the drill bit*economic hign speed steel bit general drilling*for drilling in steel,cast steel,malleable iron,sintered metal,non-ferrous ...