3/64" for 0-80 TAP, #53 for 1-72 TAP or 1/16" detent ball, 1/16" for 1-72 TAP and clearance drill for 0-80 screws, #50 for 2-56 TAP, 5/64" Clearance drill for 1-72 Screws, 3/32", 1/8", 9/64" Countersink for 2-56 socket head screw, 3/16" High Speed Steel, 1/4" High Speed Steel