Pre Tap Drill Size

Pipe Tap NPSM

Pipe Tap
NPSM
Decimal Equivalent
2in - 11-1/2
2in 1/4
2.250
1in1/2 - 11-1/2
1in 25/32
1.7812
1in1/4 - 11-1/2
1in 35/64
1.5468
1in - 11-1/2
1in 13/64
1.2031
3/4 - 14
61/64
0.9531
1/2 - 14
19MM
0.7480
3/8 - 18
.603
.603
1/4 - 18
15/32
0.4687
1/8 - 27
T
0.358
1/16 - 27
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