Center Point Drill Sets Sizes (in) 11/32, 1/16, 11/64, 1/2, 13/32, 13/64, 1/4, 15/32, 15/64, 17/64, 1/8, 19/64, 21/64, 23/64, 25/64, 25/64, 25/64, 25/64, 25/64, 25/647/64, 29/64, 3/16 31/64, 3/32, 3/8, 5/16, 5/32, 5/64, 7/16, 7/32, 7/64, 9/32, 9/64, high speed steel, black oxide finish, thunderbolt(r) web, provides longer life and faster drilling times, parabolic flute, cleans 13. 13 years 5 degree split point. Precise start without walking, 3-flat secure grip, reduces the bit slipping in the drill chuck.