Plug Chamfer - National Coarse & National Fine Fractional Machine Screw Sizes in a Index Case. 36 Pc. High Speed Steel 118° Point Drills & High Speed Steel TapsTap Sizes: 6-32, 6-40, 8-32, 8-36, 10-24, 10-32, 12-24, 12-28, 1/4-20, 1/4-28, 5/16-18, 5/16-24, 3/8-16, 3/8-24, 7/16-14, 7/16-20, 1/2-13, 1/2-20 Drill Sizes: #36, #33, #29, #29, #25, #21, #16, #15, #7, #3, F, I, 5/16, Q, U, 25/64, 27/64, 29/64