螺纹攻丝底孔的大小怎么算？（有没有表格的，附上一张）

螺丝攻孔和滚丝径对照表 公螺 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 0.985 0.985 no.3-48(2.515) 2.10 2.146 1.941 m1.4×0.3 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 3.302 m2.0×0.4 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 4.979 m2.5×0.45 2.10 2.138 2.013 5/16-18 6.60 6.731 6.401 m2.6×0.45 2.20 2.238 2.113 3/8-16 8.00 8.153 7.798 m3.0×0.5 2.50 2.599 2.459 7/16-14 9.40 9.55 9.144 m3.0×0.6 2.40 2.440 2.280 1/2-13 10.80 11.023 10.592 m3.5×0.6 2.90 3.010 2.850 9/16-12 12.20 12.446 11.989 m4.0×0.7 3.30 3.422 3.242 5/8-11 13.60 12.868 13.386 m4.0×0.75 3.25 3.326 3.106 3/4-10 16.50 18.840 16.307 m4.5×0.75 3.80 3.878 3.688 7/8-9 19.50 19.761 19.177 m5.0×0.8 4.20 4.334 4.134 1 22.20 22.606 21.971 m5.0×0.9 4.10 4.170 3.930 1-1/8-7 25.00 25.349 24.638 m6.0×1.0 5.00 5.153 4.917 1-1/4-7 28.20 28.524 27.813 m7.0×1.0 6.00 6.153 5.917 1-3/8-6 30.80 31.115 30.353 m8.0×1.25 6.80 6.912 6.647 1-1/2-6 34.00 34.290 33.528 m9.0×1.25 7.80 7.912 7.647 1-3/4-5 39.50 39.827 38.964 m10×1.5 8.50 8.676 8.376 2-4-1/2 45.20 45.593 44.679 m11×1.5 9.50 9.676 9.376 m12×1.75 10.30 10.441 10.106 m14×2.0 12.00 12.210 11.835 m16×2.0 14.00 14.210 13.835 m18×2.5 15.50 15.744 15.294 m20×2.5 17.50 17.744 17.294 m22×2.5 19.50 19.744 19.294 m24×3.0 21.00 21.252 20.752 m27×3.0 24.00 24.252 23.752 m30×3.5 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 1.182 m1.1×0.2 0.90 0.921 0.883 no.1-72(1.854) 1.55 1.612 1.474 m1.2×0.2 1.00 1.021 0.983 no.2-64(2.184) 1.85 1.912 1.756 m1.4×0.2 1.20 1.221 1.183 no.3-56(2.515) 2.10 2.197 2.025 m1.6×0.2 1.40 1.421 1.383 no.4-48(2.845) 2.40 2.458 2.271 m1.7×0.2 1.45 1.500 1.460 no.5-44(3.175) 2.70 2.740 2.551 m1.8×0.2 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 5.360 m2.6×0.35 2.20 2.246 2.186 5/16-24 6.90 7.035 6.782 m3.0×0.35 2.70 2.721 2.621 3/8-24 8.50 8.636 8.382 m3.5×0.35 3.20 3.221 3.121 7/16-20 9.90 10.033 9.729 m4.0×0.5 3.50 3.599 3.459 1/2-20 11.50 11.607 11.329 m4.5×0.5 4.00 4.099 3.959 9/16-18 12.90 13.081 12.751 m5.0×0.5 4.50 4.599 4.459 5/8-18 14.50 14.681 14.351 m5.5×0.5 5.00 5.099 4.959 3/4-16 17.50 17.678 17.323 m6.0×0.75 5.30 5.378 5.188 7/8-14 20.50 20.675 20.270 m6.0×0.5 5.50 5.550 5.400 1-12 23.20 23.571 23.114 m7.0×0.75 6.30 6.378 6.188 1-1/8-12 26.50 26.746 26.289 m7.0×0.5 6.50 6.550 6.400 1-1/4-12 29.50 29.921 29.464 m8.0×1.0 7.00 7.153 6.917 1-3/8-12 32.80 33.096 32.639 m8.0×0.75 7.30 7.378 7.188 1-1/2-12 36.00 36.271 35.814 m8.0×0.5 7.50 7.520 7.400 m9.0×1.0 8.00 8.153 7.917 m9.0×0.75 8.30 8.378 8.188 m10×1.25 8.80 8.912 8.647 m10×1.0 9.00 9.153 8.917 m10×0.75 9.30 9.378 9.188 m10×0.5 9.50 9.520 9.400 m11×1.0 10.00 10.153 9.917 m11×0.75 10.30 10.378 10.188 m12×1.5 10.50 10.676 10.376 m12×1.25 10.80 10.912 10.647 m12×1.0 11.00 11.153 10.917 m12×0.5 11.50 11.520 11.400 m14×1.5 12.50 12.676 12.376 m14×1.0 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 16.676 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 m22×2.0 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 31.676 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 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 g9 m1.0×0.25 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 8.81 m2.6×0.45 2.35 2.38 － 7/16-14 － 10.20 10.30 m3.0×0.5 2.73 2.75 － 1/2-13 － 11.27 11.82 m3.5×0.6 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 10.54 1/2-20 － 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 4.0-4.2 1/4 -32 5.60 5.690 5.486 3ba 5/16 -32 7.10 7.264 7.087 4ba 3.0-3.2 3/8 -32 8.70 8.865 8.661 5ba 2.7-2.8 7/16 -28 10.20 10.338 10.135 6ba 2.4-2.5 1/2 -28 11.80 11.938 11.709 9/16 -24 13.20 13.386 13.132 5/8 -24 14.80 14.986 14.732 3/4 -20 17.80 17.958 17.678 7/8 -20 21.00 21.133 20.853 1 -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 2.735-2.688 w 5/32 - 32 3.25 3.20 m3.0×0.6 2.56-2.53 sm1/8-44 2.769-2.722 w 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 8.880-8.015 w 1-1/8 - 7 25.00 24.80 sm7/16-28 10.466-10.401 w 1 - 1/4 - 7 28.30 28.00 sm7/16-16 10.037-9.967 sm1/2-20 11.819-11.749 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 6.35 ps 1/8 - 28 8.50 8.637 8.495 pt 1/8 - 28 8.10 8.20 8.249 8.388 1/8 - 27 8.33 8.43 8.74 ps 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 11.13 ps 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 14.68 ps 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 18.26 ps 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 23.42 ps 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 29.36 ps 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 38.10 ps 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 44.45 ps 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 20210311