1-1/2
For 1-1/2, thread standard is BSP; threads per inch (tpi) is 11; thread pitch (mm) is 2.309; major (outside) diameter (mm) is 47.803; minor diameter (mm) is 44.845, recorded from its source on 2026-08-12.
- Thread standard
- BSP our reading
- Nominal size
- 1-1/2
- Threads per inch (TPI)
- 11 verified
- Thread pitch (mm)
- 2.309 verified
- Major (outside) diameter (mm)
- 47.803 verified
- Minor diameter (mm)
- 44.845 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
1½ | 11 | 2.309 | 1.479 | 47.803 | 46.324 | 44.845 |
— amesweb.info, 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)
amesweb.info says major (outside) diameter (mm) is 47.803, as of 2026-08-12.
1½ | 11 | 2.309 | 1.479 | 47.803 | 46.324 | 44.845 |
https://amesweb.info/Screws/BSP-Thread-Chart.aspx
htsspares.com says major (outside) diameter (mm) is 47.80, as of 2026-08-12.
1-1/2 Inch BSP | 47.80 mm / 1-3/4" | 11
https://www.htsspares.com/blog/how-to/how-to-measure-your-bsp-fittings
Sources
- amesweb.infohttps://amesweb.info/Screws/BSP-Thread-Chart.aspx
- htsspares.comhttps://www.htsspares.com/blog/how-to/how-to-measure-your-bsp-fittings