2 1/2
For 2 1/2, thread standard is BSPT; threads per inch (tpi) is 11; thread pitch (mm) is 2.309; major (outside) diameter (mm) is 75.18; minor diameter (mm) is 72.23, recorded from its source on 2026-08-12.
- Thread standard
- BSPT our reading
- Nominal size
- 2 1/2 verified
- Threads per inch (TPI)
- 11 verified
- Thread pitch (mm)
- 2.309 verified
- Major (outside) diameter (mm)
- 75.18 verified
- Minor diameter (mm)
- 72.23 verified
- Thread angle (degrees)
- 55 our reading
- Governing standard
- ISO 7-1 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
<https://www.machiningdoctor.com/threadinfo-bspt/?tid=4540> BSPT Rp 2 1/2 | 2 1/2" | 11 | 2.309 | 17.5 | 0 | 75.18 | 73.71 | 72.23 | 0.216 | -999 | Rp | <https://www.machiningdoctor.com/threadinfo-bspt/?tid=4541> BSPT Rp 3 | 3" | 11 | 2.309 | 20.6 | 0 | 87.88 | 86.41 | 84.93 | 0.216 | -999 | Rp | <https://www.machiningdoctor.com/threadinfo-bspt/?tid=4542> BSPT Rp 4 | 4" | 11 | 2.309 | 25.4 | 0 | 113.03 | 111.55 | 110.07 | 0.216 | -999 | Rp | <https://www.machiningdoctor.com/threadinfo-bspt/?tid=4543> BSPT Rp 5 | 5" | 11 | 2.309 | 28.6 | 0 | 138.43 | 136.95 | 135.47 | 0.216 | -999 | Rp | <https://www.machiningdoctor.com/threadinfo-bspt/?tid=4544> BSPT Rp 6 | 6" | 11 | 2.309 | 28.6 | 0 | 163.83 | 162.35 | 160.87 | 0.216 | -999 | Tolerances and Inspection The ISO 7-1 provides tolerances only for the following dimensions:
— machiningdoctor.com, retrieved 2026-08-12
Source
- machiningdoctor.comhttps://www.machiningdoctor.com/charts/bsp/