美制粗螺纹　美制细螺纹规格 （UNC) 标准径 2级牙钻孔径规格 （UNF) 标准径 2级牙钻孔径最大最小最大最小 NO.1-64(1.854) 1.55 1.582 1.425 NO.0-80(1.524) 1.25 1.305 1.182 NO.2-56(2.184) 1.80 1.871 1.695 NO.1-72(1.854) 1.55 1.612 1.474 NO.3-48(2.515) 2.10 2.146 1.941 NO.2-64(2.184) 1.85 1.912 1.756 NO.4-40(2.845) 2.30 2.385 2.157 NO.3-56(2.515) 2.10 2.197 2.025 NO.5-40(3.175) 2.60 2.697 2.487 NO.4-48(2.845) 2.40 2.458 2.271 NO.6-32(3.505) 2.80 2.895 2.642 NO.5-44(3.175) 2.70 2.740 2.551 NO.8-32(4.166) 3.40 3.530 3.302 NO.6-40(3.505) 2.90 3.022 2.820 NO.10-24(4.826) 3.90 3.962 3.683 NO.8-36(4.166) 3.50 3.606 3.404 NO.12-24(5.486) 4.50 4.597 4.344 NO.10-32(4.826) 4.10 4.165 3.963 1/4 -20 5.10 5.257 4.979 NO.12-28(5.846) 4.60 4.724 4.496 5/16 -18 6.60 6.731 6.401 1/4-28 5.50 5.588 5.360 3/8 -16 8.00 8.153 7.798 5/16-24 6.90 7.035 6.782 7/16 -14 9.40 9.550 9.144 3/8-24 8.50 8.636 8.382 1/2 -13 10.80 11.023 10.592 7/16-20 9.90 10.033 9.729 9/16 -12 12.20 12.446 11.989 1/2-20 11.50 11.607 11.329 5/8 -11 13.60 12.868 13.386 9/16-18 12.90 13.081 12.751 3/4 -10 16.50 18.840 16.307 5/8-18 14.50 14.681 14.351 7/8 -9 19.50 19.761 19.177 3/4-16 17.50 17.678 17.323 1-8 22.20 22.606 21.971 7/8-14 20.50 20.675 20.270 1-1/8-7 25.00 25.349 24.638 1-12 23.20 23.571 23.114 1-1/4-7 28.20 28.524 27.813 1-1/8-12 26.50 26.746 26.289 1-3/8-6 30.80 31.115 30.353 1-1/4-12 29.50 29.921 29.464 1-1/2-6 34.00 34.290 33.528 1-3/8-12 32.80 33.096 32.639 1-3/4-5 39.50 39.827 38.964 1-1/2-12 36.0 36.271 35.814 2-4-1/2 45.20 45.593 44.679 　　　　美制迫牙丝攻钻孔径美制特细螺纹规格精度等级规格 （UNEF) 标准径 2级牙钻孔径 G4-G6 G7-G8 G9 最大最小 NO.2-56UNC 1.94 - - NO.12-32 4.70 4.826 4.623 NO.3-48 2.23 - - 1/4--32 5.60 5.690 5.486 NO.4-40 2.50 - - 5/16-32 7.10 7.264 7.087 NO.5-40 2.83 - - 3/8-32 8.70 8.865 8.661 NO.6-32 3.07 - - 7/16-28 10.20 10.338 10.135 NO.8-32 3.73 3.77 - 1/2-28 11.80 11.938 11.709 NO.10-24 4.24 4.30 - 9/16-24 13.20 13.386 13.132 NO.12-24 4.90 4.96 - 5/8-24 14.80 14.986 14.732 1/4-20 - 5.72 - 3/4-20 17.80 17.958 17.678 5/16-18 - 7.24 - 7/8-20 21.00 21.133 20.853 3/8-16 - 8.74 8.81 1-20 24.00 24.308 24.028 7/16-14 - 10.20 10.30 美制管螺纹 1/2-13 　 11.27 11.82 NO.2-64UNF 1.97 - - 规格钻孔径 NO.3-56 2.27 - - NPT NPS NO.4-48 2.56 - - 使用绞刀时不用绞刀时 NO.5-44 2.86 - - 1/16-27 6.10 6.25 6.35 NO.6-40 3.16 - - 1/8-27 8.33 8.43 8.74 NO.8-36 3.78 - - 1/4-18 10.72 11.13 11.13 NO.10-32 4.39 4.43 - 3/8-18 14.27 14.27 14.68 NO.12-28 4.99 5.04 - 1/2-14 17.48 17.86 18.26 1/4-28 5.85 5.90 - 3/4-14 22.63 23.01 23.42 5/16-24 7.36 7.41 - 1-11-1/2 28.58 28.98 29.36 3/8-24 - 9.00 - 1-1/4-11-1/2 37.31 37.69 38.10 7/16-20 - 10.48 10.54 1-1/2-11-1/2 43.66 44.04 44.45 1/2-20 - 12.07 12.13 2-11-1/2 55.58 55.96 56.36 　　　　英制电器螺纹　　　　　　　　规格钻孔径　　　　 2BA 4.0-4.2 　　　　 3BA 　　　　　 4BA 3.0-3.2 　　　　 5BA 2.7-2.8 　　　　　　 6BA 2.4-2.5