Irwin 1877793 Countersink Drill Bit, Specifications: 1/4 in Shank, Black Oxide, Includes: 1/4 in, 3/8 in Countersink

Precision ground 82 deg tip for countersinking most machinable metals, wood or plastic. High-speed steel with black oxide coating for corrosion resistance. 5-flute design reduces chatter for smoother drilling and extended life. Set includes one 1/4 in, one 3/8 in, one 1/2 in, one 5/8 in and one 3/4 in countersink.