Screw Thread per Inch Clearance Drill Tap Drill
No. Dia. Course Fine No. Dia. No. In mm
0 0.060 - 80 52 0.064 56 0.047 1.2
1 0.073 64 72 47 0.079 53 0.060 1.5
2 0.086 56 64 42 0.094 50 0.070 1.8
3 0.099 48 - 37 0.104 47 0.079 2.0
3 0.99 - 56 37 0.104 45 0.082 2.1
4 0.112 40 - 31 0.120 43 0.089 2.3
4 0.112 - 48 31 0.120 42 0.094 2.4
5 0.125 40 - 29 0.136 38 0.102 2.6
5 0.125 - 44 29 0.136 37 0.104 2.6
6 0.138 32 - 27 0.144 36 0.107 2.7
6 0.138 - 40 27 0.144 33 0.113 2.9
8 0.164 32 36 18 0.170 29 0.136 3.5
10 0.190 24 - 9 0.196 25 0.150 3.8
10 0.190 - 32 9 0.196 21 0.159 4.0
12 0.216 24 - 2 0.221 16 0.177 4.5
12 0.216 - 28 2 0.221 14 0.182 4.6
1/4 0.250 20 - - 17/64 7 0.201 5.1
1/4 0.250 - 28 - 17/64 3 0.213 5.5
NOTE:

Clearance drill sizes are practical values for use by engineer or technician doing his own shop work.
Tap drill sizes for use in hand tapping material such as brass or soft steel, other materials may require larger diameters than shown.