钻底孔钻头直径的计算公式:
p<1时 dT=d-p
p>1时 dT≈d-(1.04-1.08)p
式中: p-螺距(mm) 【说明】普通螺纹代号为“M”,牙型角a为60°, 一般连接
d-螺纹公称直径(mm) 多用粗牙.细牙用于薄壁零件,细牙的自锁性能较好,
dT-攻螺纹前钻头直径(mm) 螺纹强度削弱少,但易滑扣.
(mm)
| 螺纹直径d | 螺距 p | 螺纹内径 | 推荐钻头直径dT | 螺 纹直径d | 螺距 p | 螺纹内径 | 推荐钻头直径dT | ||||
| Max | Min | Max | Min | ||||||||
| M2 | 粗 | 0.4 | 1.677 | 1.567 | 1.6 | M27 | 粗 | 3 | 24.132 | 23.752 | 23.9 |
| 细 | 0.25 | 1.809 | 1.729 | 1.75 | 细 | 2 | 25.135 | 24.835 | 24.9 | ||
| M3 | 粗 | 0.5 | 2.599 | 2.459 | 2.5 | 1.5 | 25.626 | 25.376 | 25.5 | ||
| 细 | 0.35 | 2.721 | 2.621 | 2.65 | 1 | 26.118 | 25.918 | 26.0 | |||
| M4 | 粗 | 0.7 | 3.422 | 3.242 | 3.3 | M30 | 粗 | 3.5 | 26.631 | 26.211 | 26.3 |
| 细 | 0.5 | 3.599 | 3.459 | 3.5 | 细 | 3 | 26.9 | 26.88 | 26.7 | ||
| M5 | 粗 | 0.8 | 4.334 | 4.134 | 4.2 | 2 | 28.135 | 27.835 | 27.9 | ||
| 细 | 0.5 | 4.599 | 4.459 | 4.5 | 1.5 | 28.626 | 28.376 | 28.5 | |||
| M6 | 粗 | 1 | 5.118 | 4.918 | 5.0 | 1 | 29.118 | 28.918 | 29.0 | ||
| 细 | 0.75 | 5.378 | 5.118 | 5.2 | M33 | 粗 | 3.5 | 29.631 | 29.211 | 29.3 | |
| M8 | 粗 | 1.25 | 6.887 | 6.7 | 6.7 | 细 | 2 | 31.135 | 30.835 | 30.9 | |
| 细 | 1 | 7.118 | 6.918 | 7.0 | 1.5 | 31.626 | 31.376 | 31.8 | |||
| 0.75 | 7.378 | 7.118 | 7.2 | M36 | 粗 | 4 | 32.15 | 31.67 | 31.8 | ||
| M10 | 粗 | 1.5 | 8.626 | 8.376 | 8.5 | 细 | 3 | 33.132 | 32.752 | 32.9 | |
| 细 | 1.25 | 8.867 | 8.7 | 8.7 | 2 | 34.135 | 33.835 | 33.9 | |||
| 1 | 9.118 | 8.918 | 9.0 | 1.5 | 34.626 | 34.376 | 34.5 | ||||
| 0.75 | 9.378 | 9.118 | 9.2 | M39 | 粗 | 4 | 35.15 | 34.67 | 34.8 | ||
| M12 | 粗 | 1.75 | 10.386 | 10.106 | 10.2 | 细 | 3 | 36.132 | 35.752 | 35.9 | |
| 细 | 1.5 | 10.626 | 10.376 | 10.5 | 2 | 37.135 | 36.835 | 36.9 | |||
| 1.25 | 10.867 | 10.7 | 10.7 | 1.5 | 37.626 | 37.376 | 37.5 | ||||
| 1 | 11.118 | 10.918 | 11.0 | M42 | 粗 | 4.5 | 37.679 | 37.129 | 37.3 | ||
| M16 | 粗 | 2 | 14.135 | 13.835 | 13.9 | 细 | 3 | 39.132 | 38.752 | 38.9 | |
| 细 | 1.5 | 14.626 | 14.376 | 14.5 | 2 | 40.135 | 39.835 | 39.9 | |||
| 1 | 15.118 | 14.918 | 15.0 | 1.5 | 40.626 | 40.376 | 40.5 | ||||
| M20 | 粗 | 2.5 | 17.634 | 17.294 | 17.4 | M45 | 粗 | 4.5 | 40.679 | 40.129 | 40.3 |
| 细 | 2 | 18.135 | 17.835 | 17.9 | 细 | 3 | 42.132 | 41.132 | 41.9 | ||
| 1.5 | 18.626 | 18.376 | 18.5 | 2 | 43.135 | 42.835 | 42.9 | ||||
| 1 | 19.118 | 18.918 | 19.0 | 1.5 | 43.626 | 43.376 | 43.5 | ||||
| M24 | 粗 | 3 | 21.132 | 20.752 | 20.9 | M48 | 粗 | 5 | 43.118 | 42.588 | 42.7 |
| 细 | 2 | 22.135 | 21.835 | 21.9 | 细 | 3 | 45.132 | 44.752 | 44.8 | ||
| 1.5 | 22.626 | 22.376 | 22.5 | 2 | 46.135 | 45.835 | 45.9 | ||||
| 1 | 23.118 | 22.918 | 23.0 | 1.5 | 46.626 | 46.376 | 46.5 | ||||
圆柱管螺纹钻底孔的钻头尺寸表
【说明】非螺纹密封的圆柱管螺纹,代号为“G”,牙型角a为55°.多用于压力为1.568Mpa(16kgf/cm2)以下的水,煤气管路,润滑和电线管路系统.
公称
直径d
| (寸) | 每寸 牙数 n | 钻头 直 径dT (mm) | 螺距 P (mm) | 螺纹直径(mm) | ||
| 大径 dd | 中径 d2 | 小径 d1 | ||||
| G 1/8 | 28 | 8.80 | 0.907 | 9.728 | 9.147 | 8.566 |
| G 1/4 | 19 | 11.70 | 1.337 | 13.157 | 12.301 | 11.445 |
| G 3/8 | 19 | 15.20 | 16.662 | 15.806 | 14.950 | |
| G 1/2 | 14 | 18.90 | 1.814 | 20.955 | 19.793 | 18.631 |
| G 5/8 | 14 | 20.80 | 22.911 | 21.749 | 20.587 | |
| G 3/4 | 14 | 24.30 | 26.441 | 25.279 | 24.117 | |
| G 7/8 | 14 | 28.10 | 30.201 | 29.039 | 27.877 | |
| G 1 | 11 | 30.50 | 2.309 | 33.249 | 31.770 | 30.291 |
| G 11/8 | 11 | 35.20 | 37.7 | 36.418 | 34.939 | |
| G 11/4 | 11 | 39.20 | 41.910 | 40.431 | 38.952 | |
| G 13/8 | 11 | 41.60 | 44.325 | 42.846 | 41.367 | |
| G 11/2 | 11 | 45.10 | 47.803 | 46.324 | 44.845 | |
| G 13/4 | 11 | 51.00 | 53.746 | 52.267 | 50.788 | |
| G 2 | 11 | 57.00 | 59.614 | 58.135 | 56.656 | |
| G 21/4 | 11 | 63.00 | 65.710 | .231 | 62.752 | |
| G 21/2 | 11 | 72.50 | 75.184 | 73.705 | 72.226 | |
| G 23/4 | 11 | 78.50 | 81.534 | 80.055 | 78.576 | |
| G 3 | 11 | 85.20 | 87.884 | 86.405 | 84.926 | |
| G 31/2 | 11 | 97.60 | 100.330 | 98.851 | 97.372 | |
| G 4 | 11 | 110.20 | 113.030 | 111.551 | 110.072 | |
| G 5 | 11 | 135.70 | 138.430 | 136.951 | 135.472 | |
| G 6 | 11 | 161.10 | 163.830 | 162.351 | 160.872 | |
