Pre Tap Drill Size

Inch Cutting Tap

Tap
Drill Size
Decimal Equivalent
1-1/2 - 12
1in 27/64
1.4219
1-1/2 - 6
1in 11/32
1.3438
1-3/8 - 12
1in 19/64
1.2969
1-3/8 - 6
1in 7/32
1.2188
1-1/4 - 12
1in 11/64
1.1719
1-1/4 - 7
1in 7/64
1.1094
1-1/8 - 12
1in 3/64
1.0469
1-1/8 - 7
63/64
0.9844
1-12
59/64
0.9219
1-8
7/8
0.8750
7/8-14
13/16
0.8125
7/8-9
49/64
0.7656
3/4-16
11/16
0.6875
3/4-10
21/32
0.6562
5/8-18
37/64
0.5781
5/8-11
17/32
0.5312
9/16-18
33/64
0.5156
9/16-12
31/64
0.4844
1/2-20
29/64
0.4531
1/2-13
27/64
0.4219
7/16-20
25/64
0.3906
7/16-14
U
0.3680
3/8-24
Q
0.3320
3/8-16
5/16
0.3125
5/16-24
I
0.2720
5/16-18
F
0.2570
1/4-28
3
0.2130
1/4-20
7
0.2010
12-28
15
0.1800
12-24
16
0.1770
10-32
21
0.1590
10-24
26
0.1470
8-36
29
0.1360
8-32
29
0.1360
6-40
33
0.1130
6-32
36
0.1065
5-44
37
0.1040
5-40
38
0.1015
4-48
42
0.0935
4-40
43
0.0890
3-56
46
0.0810
3-48
47
0.0785
2-64
50
0.0700
2-56
50
0.0700
1-72
53
0.0595
1-64
53
0.0595
0-80
3/64
0.0469