Example designation
1/16-27 NPT
- 1/16
- Nominal pipe size, not the measured outside diameter.
- 27
- Threads per inch.
- NPT
- National pipe taper thread family.
Measure at the named plane
Diameter changes along the taper. Pipe-face, gauge-datum, and pipe-end rows refer to different axial locations. The two-wire measurement is tied to the gauge datum.
L1 through L4 describe different lengths
L1 is hand engagement, L2 is effective thread length, L3 is wrench makeup, and L4 is overall external length. Keep these labels with the values when laying out a threaded end.
A pipe size is a catalog choice
Select the nominal pipe size and TPI together. Read the pipe outside diameter separately in the profile results when checking stock or identifying a measured part.