3-1/2
For 3-1/2, thread standard is NPT; threads per inch (tpi) is 8; thread pitch (mm) is 3.1750; major (outside) diameter (mm) is 101.6000; thread angle (degrees) is 60, recorded from its source on 2026-08-12.
- Thread standard
- NPT our reading
- Nominal size
- 3-1/2
- Threads per inch (TPI)
- 8
- Thread pitch (mm)
- 3.1750
- Major (outside) diameter (mm)
- 101.6000 verified
- Thread angle (degrees)
- 60 our reading
- Governing standard
- ASME B1.20.1 our reading
Values marked our reading are our classification of what the source says — the source does not print them in those words. The quote below is the evidence for each one; judge it yourself.
What the source says
4.000 | 101.6000 |
— en.wikipedia.org, retrieved 2026-08-12
Source
- en.wikipedia.orghttps://en.wikipedia.org/wiki/National_pipe_thread