BSPT (R, Rp, Rc) Pipe Threads Chart
| BASIC DIMENSIONS AND PITCH | ||||
|---|---|---|---|---|
| BSPT designation | Nominal pipe size | TPI | Pitch (mm) | Taper |
| R 1/8 | 1/8 | 28 | 0.907 | 1:16 on diameter |
| R 1/4 | 1/4 | 19 | 1.337 | 1:16 on diameter |
| R 3/8 | 3/8 | 19 | 1.337 | 1:16 on diameter |
| R 1/2 | 1/2 | 14 | 1.814 | 1:16 on diameter |
| R 3/4 | 3/4 | 14 | 1.814 | 1:16 on diameter |
| R 1 | 1 | 11 | 2.309 | 1:16 on diameter |
| R 1 1/4 | 1 1/4 | 11 | 2.309 | 1:16 on diameter |
| R 1 1/2 | 1 1/2 | 11 | 2.309 | 1:16 on diameter |
| R 2 | 2 | 11 | 2.309 | 1:16 on diameter |
| R 2 1/2 | 2 1/2 | 11 | 2.309 | 1:16 on diameter |
| R 3 | 3 | 11 | 2.309 | 1:16 on diameter |
| R 4 | 4 | 11 | 2.309 | 1:16 on diameter |
R is the external taper form; Rp and Rc are mating internal forms. Nominal pipe size is not the thread outside diameter. Use ISO 7-1 for gauge-plane dimensions and tolerance limits.