| American Standard Taper Pipe External Thread | ||||
| Nominal size | Actual OD |
Threads per inch |
Length of engagement (tightened by hand) | Length of effective thread |
| 1/8 | 0.407 | 27 | 0.124≈3.3turns | 0.26 |
| 1/4 | 0.546 | 18 | 0.172≈3.1turns | 0.401 |
| 3/8 | 0.681 | 18 | 0.184≈3.3turns | 0.408 |
| 1/2 | 0.85 | 14 | 0.248≈3.4turns | 0.534 |
| 3/4 | 1.06 | 14 | 0.267≈3.7turns | 0.546 |
| British Standard Pipe Thread - Parallel( BSPP/BSPF) | ||||||
| Thread Size |
Outer Dia Inch |
Outer Dia MM |
Inner Dia Inch |
Inner Dia MM |
Pitch | T.P.I |
| 1/8 | 0.383 | 9.728 | 0.3372 | 8.566 | 0.907 | 28 |
| 1/4 | 0.518 | 13.157 | 0.4546 | 11.445 | 1.337 | 19 |
| 3/8 | 0.656 | 16.662 | 0.5886 | 14.95 | 1.337 | 19 |
| 1/2 | 0.825 | 20.955 | 0.7336 | 18.631 | 1.814 | 14 |
| 3/4 | 1.014 | 26.441 | 0.9496 | 24.117 | 1.814 | 14 |
| 1 | 1.309 | 33.249 | 1.1926 | 30.291 | 2.309 | 11 |
| 1-1/4 | 1.65 | 41.91 | 1.534 | 38.952 | 2.309 | 11 |
| 1-1/2 | 1.882 | 47.803 | 1.766 | 44.845 | 2.309 | 11 |
| 2 | 2.347 | 59.614 | 2.231 | 56.656 | 2.309 | 11 |