Specifications of International Thread Standards

The parallel, internal thread National Pipe Straight Fuel is coupled with tapered, external National Pipe Taper without use of a sealant.
The flank angle is 60°.

Nominal DiameterMajor Diameter
mm
Tapping
Drill Size
mm
TPIPitch
mm
1/16" - 27 NPSF7.5826.304270.940
1/8" - 27 NPSF9.9298.651270.940
1/4" - 18 NPSF13.23611.232181.411
3/8" - 18 NPSF16.67314.671181.411
1/2" - 14 NPSF20.81918.118141.814
3/4" - 14 NPSF26.16623.465141.814
1" - 11 1/2 NPSF32.71829.46411.52.209
NPSF