螺丝攻牙钻孔径和滚造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M1.0×0.250.750.7850.729NO.1-64(1.854)1.551.5821.425M1.1×0.250.850.8850.829NO.2-56(2.184)1.801.8711.695M1.2×0.250.950.9850.985NO.3-48(2.515)2.102.1461.941M1.4×0.31.101.1421.075NO.4-40(2.845)2.302.3852.157M1.6×0.351.251.3211.221NO.5-40(3.175)2.602.6972.487M1.7×0.351.351.4211.321NO.6-32(3.505)2.802.8952.642M1.8×0.351.451.5211.421NO8-32(4.166)3.403.533.302M2.0×0.41.601.6791.567NO.10-24(4.826)3.903.9623.683M2.2×0.451.751.8381.713NO.12-24(5.486)4.504.5974.344M2.3×0.41.901.9791.8671/4-205.105.2574.979M2.5×0.452.102.1382.0135/16-186.606.7316.401M2.6×0.452.202.2382.1133/8-168.008.1537.798M3.0×0.52.502.5992.4597/16-149.409.559.144M3.0×0.62.402.4402.2801/2-1310.8011.02310.592M3.5×0.62.903.0102.8509/16-1212.2012.44611.989M4.0×0.73.303.4223.2425/8-1113.6012.86813.386M4.0×0.753.253.3263.1063/4-1016.5018.84016.307M4.5×0.753.803.8783.6887/8-919.5019.76119.177M5.0×0.84.204.3344.134122.2022.60621.971M5.0×0.94.104.1703.9301-1/8-725.0025.34924.638M6.0×1.05.005.1534.9171-1/4-728.2028.52427.813M7.0×1.06.006.1535.9171-3/8-630.8031.11530.353M8.0×1.256.806.9126.6471-1/2-634.0034.29033.528M9.0×1.257.807.9127.6471-3/4-539.5039.82738.964M10×1.58.508.6768.3762-4-1/245.2045.59344.679M11×1.59.509.6769.376M12×1.7510.3010.44110.106M14×2.012.0012.21011.835M16×2.014.0014.21013.835M18×2.515.5015.74415.294M20×2.517.5017.74417.294M22×2.519.5019.74419.294M24×3.021.0021.25220.752M27×3.024.0024.25223.752M30×3.526.5026.77126.211