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Pre Tap Drill Size

Inch Cutting Tap

Tap
Drill Size
Decimal Equivalent
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
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