5/8
For 5/8, thread standard is BSP; threads per inch (tpi) is 14; thread pitch (mm) is 1.814; major (outside) diameter (mm) is 22.911; minor diameter (mm) is 20.587, recorded from its source on 2026-08-12.
- Thread standard
- BSP our reading
- Nominal size
- 5/8
- Threads per inch (TPI)
- 14
- Thread pitch (mm)
- 1.814
- Major (outside) diameter (mm)
- 22.911 verified
- Minor diameter (mm)
- 20.587
- 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
0.9020 | 22.911
— en.wikipedia.org, retrieved 2026-08-12
Sources disagree
More than one authority states this, and they do not state the same thing. Both are reproduced with the source each came from — deciding between them is yours, not ours.
Major (outside) diameter (mm)
en.wikipedia.org says major (outside) diameter (mm) is 22.911, as of 2026-08-12.
0.9020 | 22.911
https://en.wikipedia.org/wiki/British_Standard_Pipe
htsspares.com says major (outside) diameter (mm) is 22.99, as of 2026-08-12.
5/8 Inch BSP | 22.99 mm / 7/8" | 14
https://www.htsspares.com/blog/how-to/how-to-measure-your-bsp-fittings
trimantec.com says major (outside) diameter (mm) is 22.4, as of 2026-08-12.
-10 (5/8) | 14 | 22.4 | 0.88 | 20.3 | 0.80
Sources
- en.wikipedia.orghttps://en.wikipedia.org/wiki/British_Standard_Pipe
- htsspares.comhttps://www.htsspares.com/blog/how-to/how-to-measure-your-bsp-fittings
- trimantec.comhttps://trimantec.com/blogs/t/thread-identification-guide