IRWIN 49617 Wood Bit Drill Bit, Spiral Flute, 3-11/16 in L Flute, Reduced Shank, 3/8 in Dia Shank             Chrome vanadium steel heat treated at full length for extra sharpness and long life in woodworking applications. The spurred cutting head reduces splintering and ensures a smooth clean hole, wide flutes provide a fast continuous flow of chips.