1¼
For 1¼, thread standard is BSP; threads per inch (tpi) is 11; thread pitch (mm) is 2.309; major (outside) diameter (mm) is 41.91; minor diameter (mm) is 38.953, recorded from its source on 2026-08-12.
- Thread standard
- BSP our reading
- Nominal size
- 1¼ verified
- Threads per inch (TPI)
- 11 verified
- Thread pitch (mm)
- 2.309 verified
- Major (outside) diameter (mm)
- 41.91 verified
- Minor diameter (mm)
- 38.953 verified
- Thread angle (degrees)
- 55 our reading
- Governing standard
- ISO 228-1 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 | 11 | 0.0909 | 2.309 | 1.65 | 41.91 | 1.5336 | 38.953 | 0.5 | 12.7
— geminivalve.com, retrieved 2026-08-12
Source
- geminivalve.comhttps://www.geminivalve.com/bsp-thread-vs-npt-fitting/