| British Pipe Thread ( Whitworth Form) — Parallel (BSPP/BSPF) 英制管螺纹（惠氏型）圆柱（BSPP/BSPF） | |||||||||
| Thread Designation 螺纹代号 | Nominal Size 公称尺寸 | Thread Form Type 螺纹型式 | Major Diameter 大径 mm d=D | Pitch 螺距 mm p | Threads per inch 每英寸牙数 | Pitch Diameter 中径 mm d2=D2 | Minor Diameter Male Thd. 小径 外螺纹 d3 | Thread Height 牙型角 H1 | Tap Drill Diameter 钻孔直径 mm |
| G1/8 | 1/8″ | BSPP | 9.728 | 0.907 | 28 | 9.147 | 8.566 | 0.581 | 8.70 |
| G1/4 | 1/4″ | BSPP | 13.157 | 1.337 | 19 | 12.301 | 11.445 | 0.856 | 11.60 |
| G3/8 | 3/8″ | BSPP | 16.662 | 1.337 | 19 | 15.806 | 14.950 | 0.856 | 15.00 |
| G1/2 | 1/2″ | BSPP | 20.955 | 1.814 | 14 | 19.793 | 18.631 | 1.162 | 19.00 |
| G5/8 | 5/8″ | BSPP | 22.911 | 1.814 | 14 | 21.749 | 20.587 | 1.162 | 20.75 |
| G3/4 | 3/4″ | BSPP | 26.441 | 1.814 | 14 | 25.279 | 24.117 | 1.162 | 24.50 |
| G7/8 | 7/8″ | BSPP | 30.201 | 1.814 | 14 | 29.039 | 27.877 | 1.162 | 28.00 |
| G1 | 1″ | BSPP | 33.249 | 2.309 | 11 | 31.770 | 30.291 | 1.479 | 30.50 |
| G1-1/8 | 1-1/8″ | BSPP | 37.897 | 2.309 | 11 | 36.418 | 34.939 | 1.479 | 35.00 |
| G1-1/4 | 1-1/4″ | BSPP | 41.910 | 2.309 | 11 | 40.431 | 38.952 | 1.479 | 39.50 |
| G1-3/8 | 1-3/8″ | BSPP | 44.323 | 2.309 | 11 | 42.844 | 41.365 | 1.479 | 41.50 |
| G1-1/2 | 1-1/2″ | BSPP | 47.803 | 2.309 | 11 | 46.324 | 44.845 | 1.479 | 45.00 |
| G1-3/4 | 1-3/4″ | BSPP | 53.746 | 2.309 | 11 | 52.267 | 50.788 | 1.479 | 51.00 |
| G2 | 2″ | BSPP | 59.614 | 2.309 | 11 | 58.135 | 56.656 | 1.479 | 57.00 |
| G2-1/4 | 2-1/4″ | BSPP | 65.71 | 2.309 | 11 | 64.231 | 62.752 | 1.479 | 63.00 |
| G2-1/2 | 2-1/2″ | BSPP | 75.184 | 2.309 | 11 | 73.705 | 72.226 | 1.479 | 72.50 |
| G2-3/4 | 2-3/4″ | BSPP | 81.534 | 2.309 | 11 | 80.055 | 78.576 | 1.479 | 79.00 |
| 3 | 3″ | BSPP | 87.884 | 2.309 | 11 | 86.405 | 84.926 | 1.479 | 85.50 |
| G3-1/4 | 3-1/4″ | BSPP | 93.98 | 2.309 | 11 | 92.501 | 91.022 | 1.479 | 91.00 |
| G3-1/2 | 3-1/2″ | BSPP | 100.33 | 2.309 | 11 | 98.351 | 97.372 | 1.479 | 97.75 |
| G3-3/4 | 3-3/4″ | BSPP | 106.68 | 2.309 | 11 | 105.201 | 103.722 | 1.479 | 104.00 |
| G4 | 4″ | BSPP | 113.03 | 2.309 | 11 | 111.55 | 110.072 | 1.479 | 110.50 |
| G4-1/2 | 4-1/2″ | BSPP | 125.73 | 2.309 | 11 | 124.251 | 122.772 | 1.479 | 123.00 |
| G5 | 5″ | BSPP | 138.43 | 2.309 | 11 | 136.951 | 135.472 | 1.479 | 136.00 |
| G5-1/2 | 5-1/2″ | BSPP | 151.13 | 2.309 | 11 | 149.651 | 148.172 | 1.479 | 148.50 |
| G6 | 6″ | BSPP | 163.83 | 2.309 | 11 | 162.351 | 160.872 | 1.479 | 161.50 |
