| British Pipe Thread ( Whitworth Form) — Taper (BSPT) 英制管螺纹（惠氏型）锥形（BSPT） | ||||||||||
| Thread Designation 螺纹代号 R | 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 tpi | Pitch Diameter 中径 mm d2=D2 | Minor Diameter Male Thd. 小径 外螺纹 d3 | Thread Height 牙型高度 H1 | Rounding 圆弧尺寸 r | Tap Drill Diameter 钻孔直径 mm |
| R 1/16 | 1/16″ | BSPT | 7.723 | 0.907 | 28 | 7.142 | 6.561 | 0.581 | 0.125 | 6.4 |
| R 1/8 | 1/8″ | BSPT | 9.728 | 0.907 | 28 | 9.147 | 8.566 | 0.581 | 0.125 | 8.4 |
| R 1/4 | 1/4″ | BSPT | 13.157 | 1.337 | 19 | 12.301 | 11.445 | 0.856 | 0.184 | 11.2 |
| R 3/8 | 3/8″ | BSPT | 16.662 | 1.337 | 19 | 15.806 | 14.950 | 0.856 | 0.184 | 14.75 |
| R 1/2 | 1/2″ | BSPT | 20.955 | 1.814 | 14 | 19.793 | 18.631 | 1.162 | 0.249 | 18.25 |
| R 3/4 | 3/4″ | BSPT | 26.441 | 1.814 | 14 | 25.279 | 24.117 | 1.162 | 0.249 | 23.75 |
| R 1 | 1″ | BSPT | 33.249 | 2.309 | 11 | 31.77 | 30.291 | 1.479 | 0.317 | 30 |
| R 1 1/4 | 1 1/4″ | BSPT | 41.910 | 2.309 | 11 | 40.431 | 38.952 | 1.479 | 0.317 | 38.5 |
| R 1 1/2 | 1 1/2″ | BSPT | 47.803 | 2.309 | 11 | 46.324 | 44.845 | 1.479 | 0.317 | 44.5 |
| R 2 | 2″ | BSPT | 59.614 | 2.309 | 11 | 58.135 | 56.656 | 1.479 | 0.317 | 56 |
| R 2 1/2 | 2 1/2″ | BSPT | 75.184 | 2.309 | 11 | 73.705 | 72.226 | 1.479 | 0.317 | 71 |
| R 3 | 3″ | BSPT | 87.884 | 2.309 | 11 | 86.405 | 84.926 | 1.479 | 0.317 | 85.5 |
| R 4 | 4″ | BSPT | 113.030 | 2.309 | 11 | 111.551 | 110.072 | 1.479 | 0.317 | 110.5 |
| R 5 | 5″ | BSPT | 138.430 | 2.309 | 11 | 136.951 | 135.472 | 1.479 | 0.317 | 136 |
| R 6 | 6″ | BSPT | 163.830 | 2.309 | 11 | 162.351 | 160.872 | 1.479 | 0.317 | 161.5 |
