BSP Thread Chart
Complete BSP pipe thread chart: 17 sizes with dimensions per ISO 228 / BS 21.
| Thread | TPI | OD (in) | Pitch Ø (in) | Minor Ø (in) | Tap Drill (mm) |
|---|---|---|---|---|---|
| G1/8" BSP | 28 | 0.383 | 0.3601 | 0.3373 | 8.57 |
| G1/4" BSP | 19 | 0.518 | 0.4843 | 0.4506 | 11.45 |
| G3/8" BSP | 19 | 0.656 | 0.6223 | 0.5886 | 14.95 |
| G1/2" BSP | 14 | 0.825 | 0.7793 | 0.7335 | 18.63 |
| G5/8" BSP | 14 | 0.902 | 0.8563 | 0.8105 | 20.59 |
| G3/4" BSP | 14 | 1.041 | 0.9953 | 0.9495 | 24.12 |
| G7/8" BSP | 14 | 1.1 | 1.0543 | 1.0085 | 25.62 |
| G1" BSP | 11 | 1.309 | 1.2508 | 1.1926 | 30.29 |
| G1-1/8" BSP | 11 | 1.492 | 1.4338 | 1.3756 | 34.94 |
| G1-1/4" BSP | 11 | 1.65 | 1.5918 | 1.5336 | 38.95 |
| G1-1/2" BSP | 11 | 1.882 | 1.8238 | 1.7656 | 44.85 |
| G1-3/4" BSP | 11 | 2.116 | 2.0578 | 1.9996 | 50.79 |
| G2" BSP | 11 | 2.347 | 2.2888 | 2.2306 | 56.66 |
| G2-1/4" BSP | 11 | 2.587 | 2.5288 | 2.4706 | 62.75 |
| G2-1/2" BSP | 11 | 2.82 | 2.7618 | 2.7036 | 68.67 |
| G3" BSP | 11 | 3.46 | 3.4018 | 3.3436 | 84.93 |
| G4" BSP | 11 | 4.2 | 4.1418 | 4.0836 | 103.72 |