各种螺纹详细参数和钻孔直径对照表..

螺丝攻牙钻孔径和滚丝径对照表公制粗螺纹美制粗螺纹规格标准径 2级牙钻孔径规格〔UNC〕标准径 2级牙钻孔径最大最小最大最小M1.0×0.25 0.75 0.785 0.729 NO.1-64(1.854) 1.55 1.582 1.425 M1.1×0.25 0.85 0.885 0.829 NO.2-56(2.184) 1.80 1.871 1.695 M1.2×0.25 0.95 0.9850.985 NO.3-48(2.515) 2.10 2.146 1.941M1.4×0.3 1.10 1.142 1.075 NO.4-40(2.845) 2.30 2.385 2.157 M1.6×0.35 1.25 1.321 1.221 NO.5-40(3.175) 2.60 2.697 2.487 M1.7×0.35 1.35 1.421 1.321 NO.6-32(3.505) 2.80 2.895 2.642 M1.8×0.35 1.45 1.521 1.421 NO8-32(4.166) 3.40 3.53 3.302M2.0×0.4 1.60 1.679 1.567 NO.10-24(4.826) 3.90 3.962 3.683 M2.2×0.45 1.75 1.838 1.713 NO.12-24(5.486) 4.50 4.597 4.344 M2.3×0.4 1.90 1.979 1.867 1/4-20 5.10 5.257 4.979M2.5×0.45 2.10 2.138 2.013 5/16-18 6.60 6.731 6.401M2.6×0.45 2.20 2.238 2.113 3/8-16 8.00 8.153 7.798M3.0×0.5 2.50 2.599 2.459 7/16-14 9.40 9.55 9.144M3.0×0.6 2.40 2.440 2.280 1/2-13 10.80 11.023 10.592M3.5×0.6 2.90 3.010 2.850 9/16-12 12.20 12.446 11.989M4.0×0.7 3.30 3.422 3.242 5/8-11 13.60 12.868 13.386M4.0×0.75 3.25 3.326 3.106 3/4-10 16.50 18.840 16.307M4.5×0.75 3.80 3.878 3.688 7/8-9 19.50 19.761 19.177M5.0×0.8 4.20 4.334 4.134 1 22.20 22.606 21.971M5.0×0.9 4.10 4.170 3.930 1-1/8-7 25.00 25.349 24.638M6.0×1.0 5.00 5.153 4.917 1-1/4-7 28.20 28.524 27.813M7.0×1.0 6.00 6.153 5.917 1-3/8-6 30.80 31.115 30.353M8.0×1.25 6.80 6.912 6.647 1-1/2-6 34.00 34.290 33.528M9.0×1.25 7.80 7.912 7.647 1-3/4-5 39.50 39.827 38.964M10×1.5 8.50 8.676 8.376 2-4-1/2 45.20 45.593 44.679M11×1.5 9.50 9.676 9.376M12×1.75 10.30 10.441 10.106M14×2.0 12.00 12.210 11.835M16×2.0 14.00 14.210 13.835M18×2.5 15.50 15.744 15.294M20×2.5 17.50 17.744 17.294M22×2.5 19.50 19.744 19.294M24×3.0 21.00 21.252 20.752M27×3.0 24.00 24.252 23.752M30×3.5 26.50 26.771 26.211螺丝攻牙钻孔径和滚丝径对照表公制细螺纹美制细螺纹规格标准径 2级牙钻孔径规格〔UNC〕标准径 2级牙钻孔径最大最小最大最小M1.0×0.2 0.80 0.821 0.783 NO.0-80(1.524) 1.25 1.305 1.182M1.1×0.2 0.90 0.921 0.883 NO.1-72(1.854) 1.55 1.612 1.474M1.2×0.2 1.00 1.021 0.983 NO.2-64(2.184) 1.85 1.912 1.756M1.4×0.2 1.20 1.221 1.183 NO.3-56(2.515) 2.10 2.197 2.025M1.6×0.2 1.40 1.421 1.383 NO.4-48(2.845) 2.40 2.458 2.271M1.7×0.2 1.45 1.500 1.460 NO.5-44(3.175) 2.70 2.740 2.551M1.8×0.2 1.60 1.621 1.583 NO.6-40(3.505) 2.90 3.022 2.820 M2.0×0.25 1.75 1.785 1.729 NO.8-36(4.166) 3.50 3.606 3.404 M2.2×0.25 1.95 1.985 1.929 NO.10-32(4.826) 4.10 4.165 3.963 M2.3×0.25 2.05 2.061 2.001 NO.12-28(5.846) 4.60 4.724 4.496 M2.5×0.35 2.20 2.221 2.121 1/4-28 5.50 5.588 5.360M2.6×0.35 2.20 2.246 2.186 5/16-24 6.90 7.035 6.782M3.0×0.35 2.70 2.721 2.621 3/8-24 8.50 8.636 8.382M3.5×0.35 3.20 3.221 3.121 7/16-20 9.90 10.033 9.729M4.0×0.5 3.50 3.599 3.459 1/2-20 11.50 11.607 11.329M4.5×0.5 4.00 4.099 3.959 9/16-18 12.90 13.081 12.751M5.0×0.5 4.50 4.599 4.459 5/8-18 14.50 14.681 14.351M5.5×0.5 5.00 5.099 4.959 3/4-16 17.50 17.678 17.323M6.0×0.75 5.30 5.378 5.188 7/8-14 20.50 20.675 20.270M6.0×0.5 5.50 5.550 5.400 1-12 23.20 23.571 23.114M7.0×0.75 6.30 6.378 6.188 1-1/8-12 26.50 26.746 26.289M7.0×0.5 6.50 6.550 6.400 1-1/4-12 29.50 29.921 29.464M8.0×1.0 7.00 7.153 6.917 1-3/8-12 32.80 33.096 32.639M8.0×0.75 7.30 7.378 7.188 1-1/2-12 36.00 36.271 35.814M8.0×0.5 7.50 7.520 7.400M9.0×1.0 8.00 8.153 7.917M9.0×0.75 8.30 8.378 8.188M10×1.25 8.80 8.912 8.647M10×1.0 9.00 9.153 8.917M10×0.75 9.30 9.378 9.188M10×0.5 9.50 9.520 9.400M11×1.0 10.00 10.153 9.917M11×0.75 10.30 10.378 10.188. .M12×1.5 10.50 10.676 10.376M12×1.25 10.80 10.912 10.647M12×1.0 11.00 11.153 10.917M12×0.5 11.50 11.520 11.400M14×1.5 12.50 12.676 12.376M14×1.0 13.00 13.153 12.917M15×1.5 13.50 13.676 13.376M15×1.0 14.00 14.153 13.917M16×1.5 14.50 14.676 14.376M16×1.0 15.00 15.153 14.917M17×1.5 15.50 15.676 15.376M17×1.0 16.00 16.153 15.917M18×2.0 16.00 16.210 15.835M18×1.5 16.50 16.676 16.376M18×1.0 17.00 17.153 16.917M20×2.0 18.00 18.210 17.835M20×1.5 18.50 18.676 18.376M20×1.0 19.00 19.153 18.917M22×2.0 20.00 20.210 19.835M22×1.5 20.50 20.676 20.376M22×1.0 21.00 21.153 20.917M24×2.0 22.00 22.210 21.835M24×1.5 22.50 22.676 22.376M24×1.0 23.00 23.153 22.917M25×2.0 23.00 23.210 22.835M25×1.5 23.50 23.676 23.376M25×1.0 24.00 24.153 23.917M26×1.5 24.50 24.676 24.376M27×2.0 25.00 25.210 24.835M27×1.5 25.50 25.676 25.376M27×1.0 26.00 26.153 25.917M28×2.0 26.00 26.210 25.835M28×1.5 26.50 26.676 26.376M28×1.0 27.00 27.153 26.917M30×3.0 27.00 27.252 26.752M30×2.0 28.00 28.210 27.835M30×1.5 28.50 28.676 28.376M30×1.0 29.00 29.153 28.917. v .M32×2.0 30.00 30.210 29.835M32×1.5 30.50 30.676 30.376M33×3.0 30.00 30.252 29.752M33×2.0 31.00 31.210 30.835M33×1.5 31.50 31.676 31.376M35×1.5 33.50 33.676 33.376M36×3.0 33.00 33.252 32.752M36×2.0 34.00 34.210 33.835M36×1.5 34.50 34.676 34.376螺丝攻牙钻孔径和滚丝径对照表公制挤压丝攻钻孔径美制挤压丝攻钻孔径规格精度等级规格〔UNC〕精度等级G4-G6 G7-G8 G9 G4-G6 G7-G8 G9M1.0×0.25 0.86 0.88 － NO.2-56UNC 1.94 －－M1.1×0.25 0.96 0.98 － NO.3-48 2.23 －－M1.2×0.25 1.06 1.08 － NO.4-40 2.50 －－M1.4×0.3 1.24 1.25 － NO.5-40 2.83 －－M1.6×0.35 1.41 1.43 － NO.6-32 3.07 －－M1.7×0.35 1.51 1.53 － NO.8-32 3.73 3.77 －M1.8×0.35 1.61 1.63 － NO.10-24 4.24 4.3 －M2.0×0.4 1.78 1.80 － NO.12-24 4.90 4.96 －M2.2×0.45 1.95 1.98 － 1/4-20 － 5.72 －M2.3×0.4 2.08 2.10 － 5/16-18 － 7.24 －M2.5×0.45 2.25 2.28 － 3/8-16 － 8.74 8.81M2.6×0.45 2.35 2.38 － 7/16-14 － 10.20 10.30 M3.0×0.5 2.73 2.75 － 1/2-13 － 11.27 11.82M3.5×0.6 3.17 3.20 － NO.2-64UNF 1.97 －－M4.0×0.7 3.62 3.65 3.69 NO.3-56 2.27 －－M5.0×0.8 4.56 4.60 4.64 NO.4-48 2.56 －－M6.0×1.0 5.45 5.50 5.55 NO.5-44 2.86 －－M7.0×1.0 6.45 6.50 6.55 NO.6-40 3.16 －－M8.0×1.25 7.31 7.38 7.44 NO.8-36 3.78 －－M10×1.5 9.18 9.25 9.32 NO.10-32 4.39 4.43 －M10×1.25 9.31 9.38 9.44 NO.12-28 4.99 5.04 －M12×1.75 11.04 11.12 11.21 1/4-28 5.85 5.90 －M12×1.25 11.31 11.38 11.44 5/16-24 7.36 7.41 － 3/8-24 － 9.00 －. .7/16-20 － 10.48 10.541/2-20 － 12.07 12.13美制特细螺纹英制电器螺纹规格标准径 2级牙钻孔径规格钻孔径最大最小NO.12-32 4.70 4.826 4.623 2BA 4.0-4.21/4 -32 5.60 5.690 5.486 3BA5/16 -32 7.10 7.264 7.087 4BA 3.0-3.23/8 -32 8.70 8.865 8.661 5BA 2.7-2.87/16 -28 10.20 10.338 10.135 6BA 2.4-2.51/2 -28 11.80 11.938 11.7099/16 -24 13.20 13.386 13.1325/8 -24 14.80 14.986 14.7323/4 -20 17.80 17.958 17.6787/8 -20 21.00 21.133 20.8531 -20 24.00 24.308 24.028螺丝攻牙钻孔径和滚丝径对照表英制螺纹公制螺纹针车用螺纹规格(UNEF) 钻孔径规格滚丝径规格滚丝径硬材软材W 1/8 - 40 2.65 2.60 M3×0.5 2.63-2.60 SM1/8-40 2.735-2.688W 5/32 - 32 3.25 3.20 M3.0×0.6 2.56-2.53 SM1/8-44 2.769-2.722W 3/16 - 24 3.75 3.70 M3.5×0.6 3.06-3.03 SM9/64-40 3.128-3.083 W 1/4 - 20 5.10 5.00 M4.0×0.7 3.49-3.45 SM11/64-40 3.855-3.805 W 5/16 - 18 6.60 6.50 M4.0×0.75 3.45-3.41 SM3/16-32 4.205-4.155 W 3/8 - 16 8.00 7.90 M4.5×0.75 3.96-3.92 SM3/16-28 4.143-4.093 W 7/16 - 14 9.40 9.30 M5.0×0.8 4.43-4.38 SM7/32-32 5.003-4.955 W 1/2 - 12 10.70 10.50 M5.0×0.9 4.36-4.31 SM15/64-28 5.325-5.570 W 9/16 - 12 12.30 12.00 M6.0×1.0 5.30-5.25 SM1/4-40 5.890-5.735 W 5/8 - 11 13.70 13.50 M7.0×1.0 6.30-6.25 SM1/4-28 5.721-5.366 W 3/4 - 10 16.70 16.50 M8.0×1.0 7.28-7.23 SM9/32-28 6.508-6.648 W 7/8 - 9 19.50 19.30 M8.0×1.25 7.12-7.07 SM11/32-28 8.092-8.432 W1 - 8 22.40 22.00 SM3/8-28 8.880-8.015W 1-1/8 - 7 25.00 24.80 SM7/16-28 10.466-10.401W 1 - 1/4 - 7 28.30 28.00 SM7/16-16 10.037-9.967SM1/2-20 11.819-11.749. v .SM9/26-20 13.400-13.425英制管螺纹英制管螺纹美制管螺纹规格标准径钻孔径规格标准径有交牙部之长度〔最小〕中之毋螺牙内径标准长度〔最小〕中之毋螺牙内径规格钻孔径最大最小使用绞刀时不用绞刀时 NPT NPS使用绞刀时不用绞刀时PS 1/16 - 28 6.50 6.632 6.490 PT 1/16 - 28 6.10 6.20 6.244 6.384 1/16 - 27 6.10 6.25 6.35PS 1/8 - 28 8.50 8.637 8.495 PT 1/8 - 28 8.10 8.20 8.249 8.388 1/8 - 278.33 8.43 8.74PS 1/4 - 19 11.40 11.549 11.341 PT 1/4 - 19 10.70 11.00 10.962 11.174 1/4 - 18 10.72 11.13 11.13PS 3/8 - 19 15.00 15.054 14.846 PT 3/8 - 19 14.20 14.50 14.448 14.658 3/8 - 18 14.27 14.27 14.68PS 1/2 - 14 18.50 18.773 18.489 PT 1/2 - 14 17.60 18.00 17.979 18.263 1/2 - 14 17.48 17.86 18.26PS 3/4 -14 24.00 24.259 23.975 PT 3/4 - 14 23.00 23.50 23.378 23.663 3/4 - 14 22.63 23.01 23.42PS 1 - 11 30.20 30.471 30.111 PT 1- 11 29.00 29.50 29.459 29.822 1 - 11-1/2 28.58 28.98 29.36PS 1-1/4 - 11 38.80 39.132 38.772 PT 1-1/4 - 11 37.50 38.00 37.976 38.339 1-1/4-11-1/2 37.31 37.69 38.10PS 1-1/2 - 11 44.80 45.025 44.665 PT 1-1/2 - 11 43.40 44.00 43.869 44.232 1-1/2-11-1/2 43.66 44.04 44.45PS 2 - 11 56.50 56.836 56.476 PT 2 - 11 54.90 55.50 55.412 55.844 2 - 11 - 1/2 55.58 55.96 56.36。

各种制式螺纹攻牙钻孔径和滚造径对照表，太全了金属加工2015-10-17 关注作者原文地址本表所推选钻头孔径，是针对攻牙加工时，能够很容易的了解钻头直径；而依据市售之标准钻头所选定的。

在使用钻头的情况下，由于钻头的形状及尺寸、精度、被钻孔之材质等，对于所钻孔的尺寸，精度有很大影响，所以使用本表之钻孔径，若有不当之处，应实际状况适当的变更钻头直径，本表依据2级牙制订。

公制精螺纹规格标准径2级牙钻孔径最大最小M1.0×0.25 0.75 0.785 0.729M1.1×0.25 0.85 0.885 0.829M1.2×0.25 0.95 0.985 0.929M1.4×0.3 1.10 1.142 1.075M1.6×0.35 1.25 1.321 1.221M1.7×0.35 1.35 1.421 1.321M1.8×0.35 1.45 1.521 1.421M2.0×0.4 1.60 1.679 1.567M2.2×0.45 1.75 1.838 1.713M2.3×0.4 1.90 1.979 1.867M2.5×0.45 2.10 2.138 2.013M2.6×0.45 2.20 2.238 2.113M3.0×0.5 2.50 2.599 2.459M3.0×0.6 2.40 2.44 2.280M3.5×0.6 2.90 3.010 2.850M4.0×0.7 3.30 3.422 3.242M4.0×0.75 3.25 3.326 3.106M4.5×0.75 3.80 3.878 3.688M5.0×0.8 4.20 4.334 4.134M5.0×0.9 4.10 4.170 3.930M6.0×1.0 5.00 5.153 4.917M7.0×1.0 6.00 6.153 5.917M8.0×1.25 6.80 6.912 6.647M9.0×1.25 7.80 7.912 7.647M10×1.5 8.50 8.676 8.376M11×1.5 9.50 9.676 9.376M12×1.75 10.30 10.441 10.106M14×2.0 12.00 12.210 11.735M16×2.0 14.00 14.210 13.835M18×2.5 15.50 15.744 15.294M20×2.5 17.50 17.744 17.294M22×2.5 19.50 19.744 19.294M24×3.0 21.00 21.252 2.752M27×3.0 24.00 24.252 23.752M30×3.5 26.50 26.771 26.211公制细螺纹规格标准径2级牙钻孔径最大最小M1.0×0.2 0.80 0.821 0.783M1.1×0.2 0.90 0.921 0.883M1.2×0.2 1.00 1.021 0.983M1.4×0.2 1.20 1.221 0.183M1.6×0.2 1.40 1.421 1.383M1.7×0.2 1.45 1.500 1.460M1.8×0.2 1.60 1.621 1.583M2.0×0.25 1.75 1.785 1.729M2.2×0.25 1.95 1.985 1.929M2.3×0.25 2.05 2.061 2.001M2.5×0.35 2.20 2.221 2.121M2.6×0.35 2.20 2.246 2.186M3.0×0.35 2.70 2.721 2.621M3.5×0.35 3.20 3.221 3.121M4.0×0.5 3.50 3.599 3.459M4.5×0.5 4.00 4.099 3.959M5×0.5 4.50 4.599 4.459M5.5×0.5 5.00 5.099 4.959M6.0×0.75 5.30 5.378 5.188M6.0×0.5 5.50 5.550 5.400M7.0×0.75 6.30 6.378 61.88M7.0×0.5 6.50 6.550 64.00M8.0×1.0 7.00 7.153 6.917M8.0×0.75 7.30 7.378 7.188M8×0.5 7.50 7.520 7.400M9×1.0 8.00 8.153 7.917M9×0.75 8.30 8.378 8.188M10×1.25 8.80 8.912 8.647M10×1.0 9.00 9.153 8.917M10×0.75 9.30 9.378 9.188M10×0.5 9.50 9.520 9.400M11×1.0 10.00 10.153 9.917M11×0.75 10.30 10.378 10.188 M11×1.5 10.50 10.676 10.376M12×1.25 10.80 10.912 10.647 公制细螺纹规格标准径2级牙钻孔径最大最小M12×1.0 11.00 11.153 10.917M12×0.5 11.50 11.520 11.4M14×1.5 12.50 12.676 12.376M14×1.0 13.00 13.153 12.917 M15×1.5 13.50 13.676 13.376 M15×1.0 14.00 14.153 13.917 M16×1.5 14.50 14.676 14.376 M16×1.0 15.00 15.153 14.917 M17×1.5 15.50 15.676 15.376 M17×1.0 16.00 16.153 15.917 M18×2.0 16.00 16.210 15.835 M18×1.5 16.50 16.670 16.376 M18×1.0 17.00 17.153 16.917 M20×2.0 18.00 18.210 17.835 M20×1.5 18.50 18.676 18.376 M20×1.0 19.00 19.153 18.917 M20×2.0 20.00 20.210 19.835 M22×1.5 20.50 20.676 20.376 M22×1.0 21.00 21.153 20.917 M24×2.0 22.00 22.210 21.835 M24×1.5 22.50 22.676 22.376 M24×1.0 23.00 23.153 22.917 M25×2.0 23.00 23.210 22.835 M25×1.5 23.50 23.676 23.376 M25×1.0 24.00 24.153 23.917 M26×1.5 24.50 24.676 24.376 M27×2.0 25.00 25.210 24.835 M27×1.5 25.50 25.676 25.376 M27×1.0 26.00 26.153 25.917 M28×2.0 26.00 26.210 25.835 M28×1.5 26.50 26.676 26.376 M28×1.0 27.00 27.153 26.917 M30×3.0 27.00 27.252 26.752 M30×2.0 28.00 28.210 27.835 M30×1.5 28.50 28.676 28.376 M30×1.0 29.00 29.153 28.917 M32×2.0 30.00 30.210 29.835 M32×1.5 30.50 30.676 30.376 M33×3.0 30.00 30.252 29.752 M33×2.0 31.00 31.210 30.835 M33×1.5 31.50 31.376 31.376 M35×1.5 33.50 33.676 33.376 M36×3.0 33.00 33.252 32.752 M36×2.0 34.00 34.210 33.835 M36×1.5 34.50 34.676 34.376 美制细螺纹规格(UNF) 标准径2级牙钻孔径最大最小番数牙外径NO.0-80(1.524) 1.25 1.305 1.182 NO.1-72(1.854) 1.55 1.612 1.474 NO.2-64(2.184) 1.85 1.912 1.756 NO.3-56(2.515) 2.10 2.197 2.025 NO.4-48(2.845) 2.40 2.458 2.271 NO.5-44(3.175) 2.70 2.740 2.551 NO.6-40(3.505) 2.90 3.022 2.820 NO.8-36(4.166) 3.50 3.606 3.404 NO.10-32(4.826) 4.10 4.165 3.963 NO.12-28(5.846) 4.60 4.724 4.496 1/4 -28 5.50 5.588 5.3605/16 -24 6.90 7.035 6.7823/8 -24 8.50 8.636 8.3827/16 -20 9.90 10.033 9.7291/2 -20 11.50 11.607 11.3299/16 -18 12.90 13.081 12.7515/8 -18 14.50 14.681 14.3513/4 -16 17.50 14.678 17.3237/8 -14 20.50 20.675 20.2701 -12 23.20 23.571 23.1141-1/8 -12 26.50 26.746 26.2891-1/4 -12 29.50 29.921 29.4641-3/8 -12 32.80 33.096 32.4641-1/2 -12 36.00 36.270 35.814无屑丝攻钻孔径规格精度等级RH4.5.6 RH7.8 RH9M1.0×0.25 0.86 0.88 -M1.1×0.25 0.96 0.98 -M1.2×0.25 1.06 1.08 -M1.4×0.3 1.24 1.25 -M1.6×0.35 1.41 1.43 -M1.7×0.35 1.51 1.53 -M1.8×0.35 1.61 1.63 -M2.0×0.4 1.78 1.80 -M2.2×0.45 1.95 1.98 -M2.3×0.4 2.08 2.10 -M2.5×0.45 2.25 2.28 -M2.6×0.45 2.35 1.38 -M3.0×0.5 2.73 2.75 -M3.0×0.6 3.17 3.20 -M4.0×0.7 3.62 3.65 3.69M5.0×0.8 4.56 4.60 4.64M6.0×1.0 5.45 5.50 5.55M7.0×1.0 6.45 6.50 6.55M8.0×1.25 7.31 7.38 7.44M10×1.5 9.18 9.25 9.32M10×1.25 9.31 9.38 9.44M12×1.75 11.04 11.12 11.21M12×1.25 11.31 11.38 11.44注:无槽丝攻之钻孔径,在上表所列之数值,由于被加工材料之材质、硬度、形状、尺寸等之影响,多少会有所变动，因此参考上表之同时,亦请增减若干.美制管螺纹规格(UNEF) 标准径2级牙钻孔径最大最小NO.12 -32 4.70 4.826 4.6231/4 -32 5.60 5.690 5.4865/16 -32 7.10 7.264 7.0873/8 -32 8.70 8.865 8.6617/16 -28 10.20 10.338 10.1351/2 -28 11.80 11.938 11.7099/16 -28 13.20 13.386 13.1325/8 -24 14.80 14.986 14.7323/4 -20 17.80 17.958 17.6787/8 -20 21.00 21.133 20.8531 -20 24.00 24.308 24.028美制粗螺纹规格(UNC) 标准径2级牙钻孔径番数牙外径最大最小NO.1-64(1.854) 1.55 1.582 1.425NO.2-56(2.184) 1.80 1.871 1.695NO.3-48(2.515) 2.10 2.146 1.941NO.4-40(2.845) 2.30 2.385 2.157NO.5-40(3.175) 2.60 2.697 2.487NO.6-32(3.505) 2.80 2.895 2.642NO.8-32(4.166) 3.40 3.530 3.302NO.10-24(4.826) 3.90 3.962 3.682NO.12-24(5.846) 4.50 4.597 4.3441/4 -20 5.10 5.257 4.9795/16 -18 6.60 6.731 6.4013/8 -16 8.00 8.153 7.9877/16 -14 9.40 9.500 9.1441/2 -13 10.80 11.023 10.5929/16 -12 12.20 12.446 11.9895/8 -11 13.60 12.868 13.3863/4 -10 16.20 16.840 16.3071 -8 22.20 22.606 21.9711-1/8 -7 25.00 25.349 24.6381-1/4 -7 28.20 28.524 27.8131-3/8 -6 30.80 31.115 30.3531-1/2 -6 34.00 34.290 33.5281-3/4 -5 39.50 39.827 38.9642 -4-1/2 45.20 45.593 44.679英制螺纹规格钻孔径硬材软材W1/8 - 40 2.65 2.60W5/32 - 32 3.25 3.20W3/16 - 24 3.75 3.70W1/4 - 20 5.10 5.00W5/16 - 18 6.60 6.50W3/8 - 16 8.00 7.90W7/16 - 14 9.40 9.30W1/2 - 12 10.70 10.50W9/16 - 12 12.30 12.00W5/8 - 11 13.70 13.50W3/4 - 10 16.70 16.50W7/8 - 9 19.50 19.30W1 - 8 22.40 22.00W1-1/8 - 7 25.00 24.80W1-1/4 - 7 28.30 28.00英制管螺纹规格标准径钻孔径最大最小PS1/16 -28 6.50 6.632 6.490PS1/8 -28 8.50 8.637 8.495PS1/4 - 19 11.40 11.549 11.341PS3/8 - 19 15.00 15.054 14.846PS1/2 - 14 18.50 18.773 18.489PS3/4 - 14 24.00 24.259 23.975PS1 - 11 30.20 30.471 30.111PS1-1/4 -11 38.80 39.132 38.772PS1-1/2 -11 44.80 45.025 44.665PS2 - 11 56.50 56.836 56.476英制管螺纹规格标准径有效牙部之长度(最小)中之母螺牙内径标准长度(最小)中之母螺牙内径使用绞刀时不用绞刀时PT1/16 -28 6.10 6.2 6.244 6.384PT1/4 -19 10.70 11 10.962 11.174PT3/8 -19 14.20 14.5 14.448 14.658PT1/2 -14 17.60 18 17.979 18.263PT3/4 -14 23.00 23.5 23.378 23.663Pt1 -11 29.00 29.5 29.459 29.822PT1-1/4 -11 37.50 38 37.976 38.339 PT1-1/2 -11 43.40 44 43.869 44.232 Pt2 -11 54.90 55.5 55.412 55.844美制螺纹滚造径规格钻孔径NPT NPS使用绞刀时不用绞刀时1/16 -27 6.1 6.25 6.351/8 -27 8.33 8.43 8.741/4 -18 10.72 11.13 11.133/8 -18 14.27 14.27 14.681/2 -14 17.48 17.86 18.263/4 -14 22.63 23.01 23.421 -11-1/2 28.58 28.98 29.361-1/4-11-1/2 37.31 37.69 38.11-1/2-11-1/2 43.66 44.04 44.452 -11-1/2 55.58 55.96 56.36英制螺纹滚造径规格滚造径W 3/16 - 24 4.08 - 4.05W 1/4 - 20 5.51 - 5.46W 5/16 - 18 7.01 - 6.95W 3/8 - 16 8.48 - 8.41W 7/16 - 14 9.92 - 9.85W 1/2 - 12 11.31 - 11.24W 9/16 -12 12.89 - 12.82公制螺纹规格滚造径M3.0×0.5 2.63 2.60M3.0×0.6 2.56 2.53M3.5×0.6 3.06 3.03M4.0×0.7 3.49 3.45M4.0×0.75 3.45 3.41M4.5×0.75 3.96 3.92M5.0×0.8 4.43 4.38M5.0×0.9 4.36 4.31M6.0×1.0 5.30 5.25M7.0×1.0 6.30 6.25M8.0×1.0 7.28 - 7.23M8.0×1.25 7.12 - 7.07M9.0×1.25 8.12 - 8.07M10×1.25 9.10 - 9.04M10×1.5 8.97 - 8.91M11×1.5 9.97 - 9.91M12×1.5 10.92 - 10.87M12×1.75 10.79 - 10.73 M14×2.0 12.63 - 12.56M16×2.0 14.63 - 14.56M18×2.5 16.31 - 16.23M20×2.5 18.31 - 18.23M22×2.5 20.31 - 20.23针车用螺纹规格(UNC) 滚造径SM 1/8 40 2.735 -2.688 SM 1/8 44 2.769 -2.722 SM 9/64 40 3.128 -3.083 SM 11/64 40 3.855 -3.805 SM 3/16 32 4.205 -4.155 SM 3/16 28 4.143 -4.093 SM 7/32 32 5.003 -4.955 SM 15/64 28 5.325 -4.955 SM 1/4 40 5.890 -5.735 SM 1/4 28 5.721 -5.366 SM 9/32 28 6.528 -6.648 SM 11/32 28 8.092 -8.432 SM 3/8 29 8.880 -8.015 SM 7/16 30 10.466 -10.401 SM 7/16 16 10.037 -9.967 SM 1/2 20 11.819 -11.749 SM 9/16 20 13.400 -13.425 美制粗螺纹规格(UNC) 滚造径NO.5-40 2.70 - 2.67NO.6-32 2.95 - 2.91NO.8-32 3.60 - 3.57NO.10-24 4.09 - 4.05NO.12-24 4.75 - 4.701/4 -20 5.50 - 5.455/16 -18 6.98 - 6.933/8 -16 8.45 - 8.407/16 -14 9.89 - 9.831/2 -13 11.39 - 11.329/16 -12 12.87 - 12.80美制细螺纹规格(UNF) 滚造径NO.5-44 2.73 - 2.70NO.6-40 3.05 - 3.02NO.8-36 3.66 - 3.63NO.10-32 4.26 - 4.80NO.12-28 4.84 - 4.801/4 -28 5.72 - 5.685/16 -24 7.20 - 7.163/8 -24 8.79 - 8.747/16 -20 10.23 - 10.181/2 -20 11.82 - 11.76本表所推选钻头孔径,是针对攻牙加工时,能够很容易的了解钻头直径;而依据市售之标准钻头所选定的.在使用钻头的情况下,由于钻头的形状及尺寸,精度,被钻孔之材质等,对于所钻孔的尺寸,精度有很大影响,所以使用本表之钻孔径,若有不当之处,应实际状况适当的变更钻头直径,本表依据2级牙制订.公制精螺纹规格标准径2级牙钻孔径最大最小M1.0×0.25 0.75 0.785 0.729M1.1×0.25 0.85 0.885 0.829M1.2×0.25 0.95 0.985 0.929M1.4×0.3 1.10 1.142 1.075M1.6×0.35 1.25 1.321 1.221M1.7×0.35 1.35 1.421 1.321M1.8×0.35 1.45 1.521 1.421M2.0×0.4 1.60 1.679 1.567M2.2×0.45 1.75 1.838 1.713M2.3×0.4 1.90 1.979 1.867M2.5×0.45 2.10 2.138 2.013M2.6×0.45 2.20 2.238 2.113M3.0×0.5 2.50 2.599 2.459M3.0×0.6 2.40 2.44 2.280M3.5×0.6 2.90 3.010 2.850M4.0×0.7 3.30 3.422 3.242M4.0×0.75 3.25 3.326 3.106M4.5×0.75 3.80 3.878 3.688M5.0×0.8 4.20 4.334 4.134M5.0×0.9 4.10 4.170 3.930M6.0×1.0 5.00 5.153 4.917M7.0×1.0 6.00 6.153 5.917M8.0×1.25 6.80 6.912 6.647M9.0×1.25 7.80 7.912 7.647M10×1.5 8.50 8.676 8.376M11×1.5 9.50 9.676 9.376M12×1.75 10.30 10.441 10.106 M14×2.0 12.00 12.210 11.735M16×2.0 14.00 14.210 13.835M18×2.5 15.50 15.744 15.294M20×2.5 17.50 17.744 17.294M22×2.5 19.50 19.744 19.294M24×3.0 21.00 21.252 2.752M27×3.0 24.00 24.252 23.752M30×3.5 26.50 26.771 26.211公制细螺纹规格标准径2级牙钻孔径最大最小M1.0×0.2 0.80 0.821 0.783M1.1×0.2 0.90 0.921 0.883M1.2×0.2 1.00 1.021 0.983M1.4×0.2 1.20 1.221 0.183M1.6×0.2 1.40 1.421 1.383M1.7×0.2 1.45 1.500 1.460M1.8×0.2 1.60 1.621 1.583M2.0×0.25 1.75 1.785 1.729M2.2×0.25 1.95 1.985 1.929M2.3×0.25 2.05 2.061 2.001M2.5×0.35 2.20 2.221 2.121M2.6×0.35 2.20 2.246 2.186M3.0×0.35 2.70 2.721 2.621M3.5×0.35 3.20 3.221 3.121M4.0×0.5 3.50 3.599 3.459M4.5×0.5 4.00 4.099 3.959M5×0.5 4.50 4.599 4.459M5.5×0.5 5.00 5.099 4.959M6.0×0.75 5.30 5.378 5.188M6.0×0.5 5.50 5.550 5.400M7.0×0.75 6.30 6.378 61.88M7.0×0.5 6.50 6.550 64.00M8.0×1.0 7.00 7.153 6.917M8.0×0.75 7.30 7.378 7.188M8×0.5 7.50 7.520 7.400M9×1.0 8.00 8.153 7.917M9×0.75 8.30 8.378 8.188M10×1.25 8.80 8.912 8.647M10×1.0 9.00 9.153 8.917M10×0.5 9.50 9.520 9.400M11×1.0 10.00 10.153 9.917M11×0.75 10.30 10.378 10.188 M11×1.5 10.50 10.676 10.376M12×1.25 10.80 10.912 10.647 公制细螺纹规格标准径2级牙钻孔径最大最小M12×1.0 11.00 11.153 10.917M12×0.5 11.50 11.520 11.4M14×1.5 12.50 12.676 12.376M14×1.0 13.00 13.153 12.917M15×1.5 13.50 13.676 13.376M15×1.0 14.00 14.153 13.917M16×1.5 14.50 14.676 14.376M16×1.0 15.00 15.153 14.917M17×1.5 15.50 15.676 15.376M17×1.0 16.00 16.153 15.917M18×2.0 16.00 16.210 15.835M18×1.5 16.50 16.670 16.376M18×1.0 17.00 17.153 16.917M20×2.0 18.00 18.210 17.835M20×1.5 18.50 18.676 18.376M20×1.0 19.00 19.153 18.917M20×2.0 20.00 20.210 19.835M22×1.5 20.50 20.676 20.376M22×1.0 21.00 21.153 20.917M24×2.0 22.00 22.210 21.835M24×1.5 22.50 22.676 22.376M24×1.0 23.00 23.153 22.917M25×2.0 23.00 23.210 22.835M25×1.5 23.50 23.676 23.376M25×1.0 24.00 24.153 23.917M26×1.5 24.50 24.676 24.376M27×2.0 25.00 25.210 24.835M27×1.5 25.50 25.676 25.376M27×1.0 26.00 26.153 25.917M28×2.0 26.00 26.210 25.835M28×1.5 26.50 26.676 26.376M28×1.0 27.00 27.153 26.917M30×3.0 27.00 27.252 26.752M30×2.0 28.00 28.210 27.835M30×1.5 28.50 28.676 28.376M32×2.0 30.00 30.210 29.835M32×1.5 30.50 30.676 30.376M33×3.0 30.00 30.252 29.752M33×2.0 31.00 31.210 30.835M33×1.5 31.50 31.376 31.376M35×1.5 33.50 33.676 33.376M36×3.0 33.00 33.252 32.752M36×2.0 34.00 34.210 33.835M36×1.5 34.50 34.676 34.376美制细螺纹规格(UNF) 标准径2级牙钻孔径最大最小番数牙外径NO.0-80(1.524) 1.25 1.305 1.182 NO.1-72(1.854) 1.55 1.612 1.474 NO.2-64(2.184) 1.85 1.912 1.756 NO.3-56(2.515) 2.10 2.197 2.025 NO.4-48(2.845) 2.40 2.458 2.271 NO.5-44(3.175) 2.70 2.740 2.551 NO.6-40(3.505) 2.90 3.022 2.820 NO.8-36(4.166) 3.50 3.606 3.404 NO.10-32(4.826) 4.10 4.165 3.963 NO.12-28(5.846) 4.60 4.724 4.496 1/4 -28 5.50 5.588 5.3605/16 -24 6.90 7.035 6.7823/8 -24 8.50 8.636 8.3827/16 -20 9.90 10.033 9.7291/2 -20 11.50 11.607 11.3299/16 -18 12.90 13.081 12.7515/8 -18 14.50 14.681 14.3513/4 -16 17.50 14.678 17.3237/8 -14 20.50 20.675 20.2701 -12 23.20 23.571 23.1141-1/8 -12 26.50 26.746 26.2891-1/4 -12 29.50 29.921 29.4641-3/8 -12 32.80 33.096 32.4641-1/2 -12 36.00 36.270 35.814无屑丝攻钻孔径规格精度等级RH4.5.6 RH7.8 RH9M1.0×0.25 0.86 0.88 -M1.1×0.25 0.96 0.98 -M1.2×0.25 1.06 1.08 -M1.4×0.3 1.24 1.25 -M1.6×0.35 1.41 1.43 -M1.7×0.35 1.51 1.53 -M1.8×0.35 1.61 1.63 -M2.0×0.4 1.78 1.80 -M2.2×0.45 1.95 1.98 -M2.3×0.4 2.08 2.10 -M2.5×0.45 2.25 2.28 -M2.6×0.45 2.35 1.38 -M3.0×0.5 2.73 2.75 -M3.0×0.6 3.17 3.20 -M4.0×0.7 3.62 3.65 3.69M5.0×0.8 4.56 4.60 4.64M6.0×1.0 5.45 5.50 5.55M7.0×1.0 6.45 6.50 6.55M8.0×1.25 7.31 7.38 7.44M10×1.5 9.18 9.25 9.32M10×1.25 9.31 9.38 9.44M12×1.75 11.04 11.12 11.21M12×1.25 11.31 11.38 11.44注:无槽丝攻之钻孔径,在上表所列之数值,由于被加工材料之材质、硬度、形状、尺寸等之影响,多少会有所变动，因此参考上表之同时,亦请增减若干.美制管螺纹规格(UNEF) 标准径2级牙钻孔径最大最小NO.12 -32 4.70 4.826 4.6231/4 -32 5.60 5.690 5.4865/16 -32 7.10 7.264 7.0873/8 -32 8.70 8.865 8.6617/16 -28 10.20 10.338 10.1351/2 -28 11.80 11.938 11.7099/16 -28 13.20 13.386 13.1325/8 -24 14.80 14.986 14.7323/4 -20 17.80 17.958 17.6787/8 -20 21.00 21.133 20.8531 -20 24.00 24.308 24.028美制粗螺纹规格(UNC) 标准径2级牙钻孔径番数牙外径最大最小NO.1-64(1.854) 1.55 1.582 1.425NO.2-56(2.184) 1.80 1.871 1.695NO.3-48(2.515) 2.10 2.146 1.941NO.4-40(2.845) 2.30 2.385 2.157NO.5-40(3.175) 2.60 2.697 2.487NO.6-32(3.505) 2.80 2.895 2.642 NO.8-32(4.166) 3.40 3.530 3.302 NO.10-24(4.826) 3.90 3.962 3.682 NO.12-24(5.846) 4.50 4.597 4.344 1/4 -20 5.10 5.257 4.9795/16 -18 6.60 6.731 6.4013/8 -16 8.00 8.153 7.9877/16 -14 9.40 9.500 9.1441/2 -13 10.80 11.023 10.5929/16 -12 12.20 12.446 11.9895/8 -11 13.60 12.868 13.3863/4 -10 16.20 16.840 16.3077/8 -9 19.50 19.761 19.1771 -8 22.20 22.606 21.9711-1/8 -7 25.00 25.349 24.6381-1/4 -7 28.20 28.524 27.8131-3/8 -6 30.80 31.115 30.3531-1/2 -6 34.00 34.290 33.5281-3/4 -5 39.50 39.827 38.9642 -4-1/2 45.20 45.593 44.679英制螺纹规格钻孔径硬材软材W1/8 - 40 2.65 2.60W5/32 - 32 3.25 3.20W3/16 - 24 3.75 3.70W1/4 - 20 5.10 5.00W5/16 - 18 6.60 6.50W3/8 - 16 8.00 7.90W7/16 - 14 9.40 9.30W1/2 - 12 10.70 10.50W9/16 - 12 12.30 12.00W5/8 - 11 13.70 13.50W3/4 - 10 16.70 16.50W7/8 - 9 19.50 19.30W1 - 8 22.40 22.00W1-1/8 - 7 25.00 24.80W1-1/4 - 7 28.30 28.00英制管螺纹规格标准径钻孔径最大最小PS1/16 -28 6.50 6.632 6.490PS1/8 -28 8.50 8.637 8.495PS1/4 - 19 11.40 11.549 11.341PS3/8 - 19 15.00 15.054 14.846PS1/2 - 14 18.50 18.773 18.489PS3/4 - 14 24.00 24.259 23.975PS1 - 11 30.20 30.471 30.111PS1-1/4 -11 38.80 39.132 38.772PS1-1/2 -11 44.80 45.025 44.665PS2 - 11 56.50 56.836 56.476英制管螺纹规格标准径有效牙部之长度(最小)中之母螺牙内径标准长度(最小)中之母螺牙内径使用绞刀时不用绞刀时PT1/16 -28 6.10 6.2 6.244 6.384PT1/8 -28 8.10 8.2 8.249 8.388PT1/4 -19 10.70 11 10.962 11.174PT3/8 -19 14.20 14.5 14.448 14.658PT1/2 -14 17.60 18 17.979 18.263PT3/4 -14 23.00 23.5 23.378 23.663Pt1 -11 29.00 29.5 29.459 29.822PT1-1/4 -11 37.50 38 37.976 38.339PT1-1/2 -11 43.40 44 43.869 44.232Pt2 -11 54.90 55.5 55.412 55.844美制螺纹滚造径规格钻孔径NPT NPS使用绞刀时不用绞刀时1/16 -27 6.1 6.25 6.351/8 -27 8.33 8.43 8.741/4 -18 10.72 11.13 11.133/8 -18 14.27 14.27 14.681/2 -14 17.48 17.86 18.263/4 -14 22.63 23.01 23.421 -11-1/2 28.58 28.98 29.361-1/4-11-1/2 37.31 37.69 38.11-1/2-11-1/2 43.66 44.04 44.452 -11-1/2 55.58 55.96 56.36英制螺纹滚造径规格滚造径W 3/16 - 24 4.08 - 4.05W 1/4 - 20 5.51 - 5.46W 5/16 - 18 7.01 - 6.95W 3/8 - 16 8.48 - 8.41W 7/16 - 14 9.92 - 9.85W 1/2 - 12 11.31 - 11.24W 9/16 -12 12.89 - 12.82规格滚造径M3.0×0.5 2.63 2.60M3.0×0.6 2.56 2.53M3.5×0.6 3.06 3.03M4.0×0.7 3.49 3.45M4.0×0.75 3.45 3.41M4.5×0.75 3.96 3.92M5.0×0.8 4.43 4.38M5.0×0.9 4.36 4.31M6.0×1.0 5.30 5.25M7.0×1.0 6.30 6.25M8.0×1.0 7.28 - 7.23M8.0×1.25 7.12 - 7.07M9.0×1.25 8.12 - 8.07M10×1.25 9.10 - 9.04M10×1.5 8.97 - 8.91M11×1.5 9.97 - 9.91M12×1.5 10.92 - 10.87M12×1.75 10.79 - 10.73 M14×2.0 12.63 - 12.56M16×2.0 14.63 - 14.56M18×2.5 16.31 - 16.23M20×2.5 18.31 - 18.23M22×2.5 20.31 - 20.23针车用螺纹规格(UNC) 滚造径SM 1/8 40 2.735 -2.688 SM 1/8 44 2.769 -2.722 SM 9/64 40 3.128 -3.083 SM 11/64 40 3.855 -3.805 SM 3/16 32 4.205 -4.155 SM 3/16 28 4.143 -4.093 SM 7/32 32 5.003 -4.955 SM 15/64 28 5.325 -4.955 SM 1/4 40 5.890 -5.735 SM 1/4 28 5.721 -5.366 SM 9/32 28 6.528 -6.648 SM 11/32 28 8.092 -8.432 SM 3/8 29 8.880 -8.015 SM 7/16 30 10.466 -10.401 SM 7/16 16 10.037 -9.967 SM 1/2 20 11.819 -11.749 SM 9/16 20 13.400 -13.425规格(UNC) 滚造径NO.5-40 2.70 - 2.67NO.6-32 2.95 - 2.91NO.8-32 3.60 - 3.57NO.10-24 4.09 - 4.05NO.12-24 4.75 - 4.701/4 -20 5.50 - 5.455/16 -18 6.98 - 6.933/8 -16 8.45 - 8.407/16 -14 9.89 - 9.831/2 -13 11.39 - 11.329/16 -12 12.87 - 12.80美制细螺纹规格(UNF) 滚造径NO.5-44 2.73 - 2.70NO.6-40 3.05 - 3.02NO.8-36 3.66 - 3.63NO.10-32 4.26 - 4.80NO.12-28 4.84 - 4.801/4 -28 5.72 - 5.685/16 -24 7.20 - 7.163/8 -24 8.79 - 8.747/16 -20 10.23 - 10.181/2 -20 11.82 - 11.76来源：直观学机械推荐阅读1.钢价惨烈下跌风暴即将来临?不要以为和你没关系2.世界名刀大全，简直太漂亮了免责声明：本文系网络转载，版权归原作者所有。

註(1)M1.4以下等級：5H、M1.6以上等級：6H (2)基於JIS B 0209-1982標準
(2)基於JIS B 0211-1982標準
螺纹下孔径表
螺纹下孔径表
螺纹下孔径表。

螺纹下孔径表
美制管用耐密斜行螺纹(NPTF‧NPSF) (單位：
上述钻头直径來源於美制管用耐密斜行螺纹ANSI B1.20.3—1957 Dryseal Pipe Threads (Inch)標準。

螺纹下孔径表(無屑絲攻用)
螺纹下孔径表(無屑絲攻用)
螺纹下孔径表(無屑絲攻用)
螺纹下孔径表(無屑絲攻用)
螺纹下孔径表(護套螺纹用)
螺纹下孔径表(護套螺纹用)
螺纹下孔径表(護套螺纹用)
各種換算表
管用螺絲基準寸法(mm)
美制螺絲外徑公厘(mm)換算表。

常用螺纹代号及钻头直径常用螺纹代号及钻头直径1、普通标准公制内螺纹底孔直径计算方法代号：M底孔直径d：D-T*1.0825例：M30d=30-3.5*1.0825=26.21（最小）2、普通细牙螺纹内螺纹底孔直径计算方法代号：M*T底孔直径d：D-T*1.0825例：M30*2d=30-2*1.0825=27.84（最小）3、圆柱管螺纹底孔直径尺寸表代号：G牙型角：55°公称直径（英寸）每寸牙数钻头直径（mm）公称直径（英寸）每寸牙数底孔直径（mm）1/8288.6~8.811130.3~30.51/41911.5~11.711/81135~35.23/81915~15.211/41139~39.21/21418.6~18.913/81141.4~41.65/81420.6~20.811/21144.9~45.13/41424.1~24.313/41150.8~517/81427.9~28.121156.7~57 4、圆锥管螺纹底孔直径尺寸表1)、55°圆锥管螺纹代号：KG、ZG、RC（内）、R（外）牙型角：55°锥度=1:16斜角=1°47′24″公称直径每寸牙数有效长度基面长度基面外径底孔直径1/8289 4.59.7298.2701/41911613.15811.073/81912616.66314.5761/214157.520.95618.163/414179.526.44223.525111191133.25029.6111/411221341.91238.14111/211231447.80543.972211261659.61655.659 2)、60°圆锥管螺纹代号：Z、K、NPT牙型角：60°锥度=1:16斜角=1°47′24″公称直径每寸牙数有效长度基面长度基面外径底孔直径1/1627 6.5 4.0647.895 6.1351/8277 4.57210.2728.4801/4189.5 5.08013.57210.9963/81810.5 6.09617.05514.4161/21413.58.12821.22317.813/414148.61126.56823.128111.517.510.16033.22829.05911/411.51810.66841.95837.78411/211.518.510.66848.05443.853211.51911.07460.09255.866审核：制表：。

螺纹底孔直径一、螺纹底孔直径计算式螺纹底孔直径可参照表1、表2的公式计算，也可查表3至表11。

表1 加工米制普通螺纹底孔钻头直径D的计算公式适用范围1D = d – t式中 d：螺纹的公称直径t：螺距（1）螺距t<1；（2）工件材料塑性较大；（3）孔扩张量适中。

2 D = d – (1.04～1.08)t （1）螺距t<1；（2）工件材料塑性较小；（3）孔扩张量较小。

表2 加工英制螺纹底孔钻头直径的计算公式(mm)螺纹公称直径(英寸)铸铁与青铜 钢与黄铜3/16"～5/8" D = 25.4·(d - 1/n) D = 25.4·(d - 1/n) + 0.1 3/4"～1 1/2" D = 25.4·(d - 1/n) D = 25.4·(d - 1/n) + 0.2注：n—每英寸牙数·2·二、螺纹底孔直径表表3 米制粗牙螺纹攻丝前用的钻头直径(mm)螺 纹小 直 径 级 别公称直径 螺距5Hmax 6Hmax7Hmax5H、6H、7Hmin钻头直径1 1.2 1.6 2 2.5 34568 10 12 14 16 18 20 22 24 0.250.250.350.40.450.50.70.811.251.51.75222.52.52.530.7850.9851.3011.6572.1122.5713.3824.2945.0076.8598.61210.37112.13514.13515.64917.64919.64921.1521.3211.6792.1382.5993.4224.3345.1536.9128.67610.44112.21014.21015.74417.74419.74421.2522.6393.4664.3845.2176.9828.75110.53112.31014.31015.85417.85419.85421.3820.7290.9291.2211.5612.0132.4593.2424.1344.9176.6478.37610.10611.83513.83515.29417.29419.29420.7540.750.951.251.602.052.503.304.205.006.808.5010.212.014.015.517.519.521.0·3·表4 米制细牙螺纹攻丝前用的钻头直径(mm)螺 纹小 直 径 级 别公称直径 螺距 5Hmax 6Hmax7Hmax5H、6H、7Hmin钻头直径2.5 3 0.352.2012.7012.2212.7212.1212.6212.152.654 5 0.53.5714.5713.5994.5993.6394.6393.4594.4593.504.5068 10 0.755.3387.3389.3385.3787.3789.3785.4247.4249.4245.1887.1889.1885.707.209.208 10 12 1416 18 20 22 24 17.1079.10711.10713.10715.10717.10719.10721.10723.1077.2179.21711.21713.21715.21717.21719.21721.21723.2177.2179.21711.21713.21715.21717.21719.21721.21723.2176.9178.91710.91712.91714.91716.91718.91720.91722.9177.009.0011.013.015.017.019.021.023.01012 14 1.258.85910.85912.8598.91210.91212.9128.98210.98212.9828.64710.64712.6478.8010.812.812141516 18 20 22 1.510.61212.61213.61214.61216.61218.61220.61210.67612.67613.67614.67616.67618.67620.67610.75112.75113.75114.75116.75118.75120.75110.37612.37613.37614.37616.37618.37620.37610.512.513.514.516.518.520.5·4·螺 纹小 直 径 级 别公称直径 螺距 5Hmax 6Hmax7Hmax5H、6H、7Hmin钻头直径2425 1.522.61223.61222.67623.67622.75123.75122.37623.37622.523.518 20222425 216.13518.13520.13522.13523.13516.21018.21020.21022.21023.21016.31018.31020.31022.31023.31015.83517.83519.83521.83522.83516.018.020.022.023.0表5 英国标准粗牙惠氏螺纹Ｂ、Ｓ、Ｗ攻丝前用的钻头直径(mm)钻 头 直 径公称直径 （英寸） 每英寸牙数铸铁、青铜、黄铜钢、可锻铸铁3/16 1/45/16 3/81/25/83/47/811 1/8 1 1/4 1 1/2 1 3/4 2 242018161211109877654 1/23.85.16.68.010.613.616.619.622.325.028.234.039.545.33.95.26.78.110.713.816.819.722.525.228.434.239.745.6·5·表6 英寸制统一粗牙螺纹UNC 攻丝前用的钻头直径(mm)螺 纹小 直 径 级 别公称直径 （英寸） 每英寸牙 数螺 距2B max 3B max 2B、3B min 钻头 直径 No.1 No.2 No.3 No.4 No.5 64 56 48 40 40 0.397 0.454 0.529 0.635 0.635 1.5821.8722.1462.3852.697 1.5821.8722.1462.3852.697 1.4251.6941.9412.1562.487 1.55 1.85 2.10 2.35 2.65 No.6 No.8 No.10 No.12 1/4 32 32 24 24 20 0.794 0.794 1.058 1.058 1.270 2.8963.5313.9624.5975.268 2.8963.5283.9504.5905.250 2.6423.3023.6834.3434.976 2.85 3.50 3.90 4.60 5.10 5/16 3/8 7/16 1/2 9/16 18 16 14 13 12 1.411 1.588 1.814 1.954 2.117 6.7848.1649.55011.01312.456 6.6808.0829.44110.88112.301 6.4117.8059.14910.58411.996 6.60 8.00 9.40 10.80 12.20 5/8 3/4 7/8 1 1 1/8 11 10 9 8 7 2.309 2.540 2.822 3.175 3.629 13.86816.83319.74822.59825.34913.69316.62419.52022.34425.08213.37616.29919.16921.96324.64813.50 16.50 19.50 22.25 25.00 1 1/4 1 3/8 1 1/2 1 3/4 2 7 6 6 5 4 1/23.6294.233 4.2335.080 5.64428.52431.12034.29539.81445.59828.25830.85134.02639.56045.36727.82330.34333.51938.95144.68928.00 30.75 34.00 39.50 45.00·6· 表7 英寸制统一细牙螺纹UNF 攻丝前用的钻头直径(mm)螺 纹小 直 径 级 别公称直径 （英寸） 每英寸牙 数螺 距2B max 3B max 2B、3B min 钻头 直径 No.0 No.1 No.2 No.3 No.4 80 72 64 56 48 0.318 0.353 0.397 0.454 0.529 1.3061.6131.9132.1972.459 1.3061.6131.9132.1972.459 1.1811.4731.7552.0242.271 1.25 1.55 1.90 2.15 2.40 No.5 No.6 No.8 No.10 No.12 44 40 36 32 28 0.577 0.635 0.706 0.794 0.907 2.7413.0233.6074.1664.724 2.7413.0123.5974.1684.717 2.5502.8193.4043.9624.496 2.70 2.95 3.50 4.10 4.70 1/4 5/16 3/8 7/16 1/2 28 24 24 20 20 0.907 1.058 1.058 1.270 1.270 5.5807.0388.62610.03011.618 5.5636.9958.5659.94711.524 5.3676.7928.3799.73811.326 5.50 6.90 8.50 9.90 11.50 9/16 5/8 3/4 7/8 1 18 18 16 14 12 1.411 1.411 1.588 1.814 2.117 13.08414.67117.68920.66323.56912.96914.55417.54620.49323.36312.76114.34817.33020.26223.10912.90 14.50 17.50 20.40 23.25 1 1/8 1 1/4 1 3/8 1 1/2 12 12 12 122.117 2.117 2.117 2.11726.74429.91933.09436.26926.53829.71332.88836.06326.28429.45932.63435.80926.50 29.50 32.75 36.00·7·表8 GB7307-87、ISO228/1-1982非螺纹密封的管螺纹攻丝前用的钻头直径(mm)螺 纹小 直 径 公称直径 （英寸） 每英寸 牙 数 螺 距 max min 钻头 直径 1/8 1/4 3/8 1/2 5/8 3/4 7/8 1 1 1/4 1 1/2 1 3/4 2 28 19 19 14 14 14 14 11 11 11 11 110.907 1.337 1.337 1.814 1.814 1.814 1.814 2.309 2.309 2.309 2.309 2.3098.848 11.890 16.395 19.172 21.128 24.658 28.418 30.931 39.592 45.485 51.428 75.2968.566 11.445 14.950 18.631 20.587 24.117 27.877 30.291 38.952 44.845 50.788 56.5568.80 11.80 15.25 19.00 21.00 24.50 28.25 30.75 39.50 45.00 51.00 57.00·8· 表9 GB7306-87、ISO7/1-1982用螺纹密封的管螺纹攻丝前用的钻头直径(mm)螺 纹小 直 径 公称直径 （英寸） 每英寸 牙 数 螺 距 max min 钻头 直径 1/8 1/4 3/8 1/2 3/4 1 1 1/4 1 1/2 2 28 19 19 14 14 11 11 11 110.907 1.337 1.337 1.814 1.814 2.309 2.309 2.309 2.3098.637 11.549 15.054 18.773 24.259 30.471 39.132 45.025 56.8368.495 11.341 14.846 18.489 23.975 30.111 38.772 44.665 56.4768.60 11.50 15.00 18.50 24.00 30.25 39.00 45.00 56.50·9·表10 美标(NPT、NPSC)管螺纹底孔推荐的麻花钻直径(英寸)锥 螺 纹公称直径使用铰刀 不用铰刀直管螺纹1 2 3 41/161/81/43/81/23/411 1/4 1 1/2 22 1/2 21/6427/649/1611/1657/641 1/21 15/321 23/322 3/162 19/32*0.240*0.328*0.422*0.562*0.688*0.891*1.1251.4691.7192.1882.5947/169/1645/6429/321 9/641 31/641 47/642 13/642 5/8*0.246*0.332*0.438*0.562*0.703*0.906*1.1411.4841.7342.2032.6251/411/327/1637/6423/3259/641 5/321 1/21 3/42 7/322 21/32*0.250*0.344*0.438*0.578*0.719*0.922*1.1561.5001.7502.2192.656注：*为美国标准麻花钻尺寸·10·表11 美标(NPTF、NPSI)干密封管螺纹底孔推荐的麻花钻直径(英寸)锥 螺 纹公称直径使用铰刀 不用铰刀直管螺纹1 2 3 41/161/81/43/81/23/411 1/4 1 1/2 22 1/23 21/6427/649/1611/1657/641 1/81 15/321 45/642 3/162 19/323 7/32*0.234*0.328*0.422*0.562*0.688*0.891*1.1251.4691.7032.1882.5943.2197/1627/6445/6459/641 5/321 1/21 47/642 7/322 41/643 17/64*0.246*0.339*0.436*0.578*0.703*0.922*1.1561.5001.7342.2192.6413.2661/4*11/3227/6423/32*59/641 5/32*0.250*0.344*0.444*0.578*0.719*0.922*1.156注：*为美国标准麻花钻尺寸。