1/4
For 1/4, thread standard is BSPP; threads per inch (tpi) is 19; thread pitch (mm) is 1.337; major (outside) diameter (mm) is 13.157; minor diameter (mm) is 11.445, recorded from its source on 2026-08-12.
- Thread standard
- BSPP our reading
- Nominal size
- 1/4 verified
- Threads per inch (TPI)
- 19 verified
- Thread pitch (mm)
- 1.337 verified
- Major (outside) diameter (mm)
- 13.157 verified
- Minor diameter (mm)
- 11.445 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
BSPP G 1/4 | 1/4" | 19 | 1.337 | 13.157 | 12.301 | 11.445
— machiningdoctor.com, retrieved 2026-08-12
Source
- machiningdoctor.comhttps://www.machiningdoctor.com/charts/bsp/