螺丝攻牙钻孔径和滚造径对照表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纹刀时不用纹刀时NPTNPS使用绞刀时不用绞刀时PS 1/16 - 286.506.6326.490PT 1/16 - 286.106.206.2446.3841/16 - 276.106.256.35PS 1/8 - 288.508.6378.495PT 1/8 - 288.108.208.2498.3881/8 - 278.338.438.74PS 1/4 - 1911.4011.54911.341PT 1/4 - 1910.7011.0010.96211.1741/4 - 1810.7211.1311.13PS 3/8 - 1915.0015.05414.846PT 3/8 - 1914.2014.5014.44814.6583/8 - 1814.2714.2714.68PS 1/2 - 1418.5018.77318.489PT 1/2 - 1417.6018.0017.97918.2631/2 - 1417.4817.8618.26PS 3/4 -1424.0024.25923.975PT 3/4 - 1423.0023.5023.37823.6633/4 - 1422.6323.0123.42PS 1 - 1130.2030.47130.111PT 1- 1129.0029.5029.45929.8221 - 11-1/228.5828.9829.36PS 1-1/4 - 1138.8039.13238.772PT 1-1/4 - 1137.5038.0037.97638.3391-1/4-11-1/237.3137.6938.10PS 1-1/2 - 1144.8045.02544.665PT 1-1/2 - 1143.4044.0043.86944.2321-1/2-11-1/243.6644.0444.45PS 2 - 1156.5056.83656.476PT 2 - 1154.9055.5055.41255.8442 - 11 - 1/255.5855.9656.36