1¼
For 1¼, thread standard is NPT; threads per inch (tpi) is 11½; thread pitch (mm) is 2.20878; major (outside) diameter (mm) is 42.16; thread angle (degrees) is 60, recorded from its source on 2026-08-12.
- Thread standard
- NPT our reading
- Nominal size
- 1¼ verified
- Threads per inch (TPI)
- 11½ verified
- Thread pitch (mm)
- 2.20878 verified
- Major (outside) diameter (mm)
- 42.16 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
1¼ | 11½ | 0.08696 | 2.20878 | 1.66 | 42.16
— geminivalve.com, retrieved 2026-08-12
Source
- geminivalve.comhttps://www.geminivalve.com/bsp-thread-vs-npt-fitting/