最大最小最大最小G4-G6G7-G8G9M1.0*0.250.750.7850.729M12*1.011.0011.15310.917M1.0*0.250.860.88M1.1*0.250.850.8850.829M12*0.511.5011.52011.400M1.1*0.250.960.98最大M1.2*0.250.950.9850.929M14*1.512.5012.67612.376M1.2*0.25 1.06 1.08G 1/167.72 6.84M1.4*0.3 1.10 1.142 1.075M14*1.013.0013.15312.917M1.4*0.3 1.24 1.25G(PF)1/89.738.85M1.6*0.35 1.25 1.321 1.221M15*1.513.5013.67613.376M1.6*0.35 1.41 1.431/413.1611.89M1.7*0.35 1.35 1.421 1.321M15*1.014.0014.15313.917M1.7*0.35 1.51 1.533/816.6615.40M1.8*0.35 1.45 1.521 1.421M16*1.514.5014.67614.376M1.8*0.35 1.61 1.631/220.9619.17M2.0*0.4 1.60 1.679 1.567M16*1.015.0015.15314.917M2*0.4 1.78 1.805/822.9121.13M2.2*0.45 1.75 1.838 1.713M17*1.515.5015.67615.376M2.2*0.45 1.95 1.983/426.4424.66M2.3*0.4 1.90 1.979 1.867M17*1.016.0016.15315.917M2.3*0.4 2.08 2.107/830.2028.42M2.5*0.45 2.10 2.138 2.013M18*2.016.0016.21015.835M2.5*0.45 2.25 2.28133.2530.93M2.6*0.45 2.20 2.238 2.113M18*1.516.5016.67616.376M2.6*0.45 2.35 2.38 1.12537.9035.58M3.0*0.5 2.50 2.599 2.459M18*1.017.0017.15316.917M3.0*0.5 2.73 2.75 1.2541.9139.59M3.0*0.6 2.40 2.440 2.280M20*2.018.0018.21017.835M3.5*0.6 3.17 3.20 1.37544.3242.01M3.5*0.6 2.90 3.010 2.850M20*1.518.5018.67618.376M4.0*0.7 3.62 3.65 3.69 1.547.8049.02M4.0*0.7 3.30 3.422 3.242M20*1.019.0019.15318.917M5.0*0.8 4.56 4.60 4.64 1.62551.9150.79M4.0*0.75 3.25 3.326 3.106M22*2.020.0020.21019.835M6.0*1.0 5.45 5.50 5.55 1.7553.7556.66 M4.5*0.75 3.80 3.878 3.688M22*1.520.5020.67620.376M7.0*1.0 6.45 6.50 6.552 59.61 M5.0*0.8 4.20 4.334 4.134M22*1.021.0021.15320.917M8.0*1.257.317.387.44M5.0*0.9 4.10 4.170 3.930M24*2.022.0022.21021.835M10*1.59.189.259.32M6.0*1.0 5.00 5.153 4.917M24*1.522.5022.67622.376M10*1.259.319.389.44M7.0*1.0 6.00 6.153 5.917M24*1.023.0023.15322.917M12*1.7511.0411.1211.21M8.0*1.25 6.80 6.912 6.647M25*2.023.0023.21022.835M12*1.25 11.3111.3811.44 M9.0*1.257.807.9127.647M25*1.523.5023.67623.376最大M10*1.58.508.6768.376M25*1.024.0024.15323.917PS 1/16 - 28 6.50 6.632M11*1.59.509.6769.376M26*1.524.5024.67624.376PS 1/8 - 288.508.637M12*1.7510.3010.44110.106M27*2.025.0025.21024.835PS 1/4 - 1911.4011.549M14*2.012.0012.21011.835M27*1.525.5025.67625.376PS 3/8 - 1915.0015.054M16*2.014.0014.21013.835M27*1.026.0026.15325.917PS 1/2 - 1418.5018.773M18*2.515.5015.74415.294M28*2.026.0026.21025.835PS 3/4 - 1424.0024.259M20*2.517.5017.74417.294M28*1.526.5026.67626.376PS 1 - 1130.2030.471M22*2.519.5019.74419.294M28*1.027.0027.15326.917规格PS 1-1/4 - 1138.8039.132M24*3.021.0021.25220.752M30*3.027.0027.25226.752(UNC) 最大最小PS 1-1/2 - 1144.8045.025M27*3.024.0024.25223.752M30*2.028.0028.21027.835 (螺丝牙外径) PS 2 - 11 56.50 56.836 M30*3.5 26.50 26.771 26.211 M30*1.528.5028.67628.376No.1-64(1.854) 1.55 1.582 1.425M30*1.029.0029.15328.917No.2-56(2.184) 1.80 1.871 1.695M32*2.030.0030.21029.835No.3-48(2.515) 2.10 2.146 1.941M32*1.530.5030.67630.376No.4-40(2.845) 2.30 2.385 2.157M33*3.030.0030.25229.752No.5-40(3.175) 2.60 2.697 2.487M33*2.031.0031.21030.835No.6-32(3.505) 2.80 2.895 2.642最大最小M33*1.531.5031.67631.376No.8-32(4.166) 3.40 3.530 3.302M1.0*0.20.800.8210.783M35*1.533.5033.67633.376No.10-24(4.826) 3.90 3.962 3.683M1.1*0.20.900.9210.883M36*3.033.0033.25232.752No.12-24(5.486) 4.50 4.597 4.344PT 1/16 -28 6.10 6.20 6.244 6.384M1.2*0.2 1.00 1.0210.983M36*2.034.0034.21033.8351/4 - 20 5.10 5.257 4.979PT 1/8 -288.108.208.4298.388M1.4*0.2 1.20 1.221 1.183M36*1.5 34.50 34.67634.376 5/16 - 18 6.60 6.731 6.401PT 1/4 -1910.7011.0010.96211.174M1.6*0.2 1.40 1.421 1.3833/8 - 168.008.1537.798PT 3/8 -1914.2014.5014.44814.658M1.7*0.2 1.45 1.500 1.4607/16 - 149.409.5509.144PT 1/2 -1417.6018.0017.97918.263M1.8*0.2 1.60 1.621 1.5831/2 - 1310.8011.02310.592PT 3/4 -1423.0023.5023.37823.663M2.0*0.25 1.75 1.785 1.7299/16 - 1212.2012.44611.989PT 1 -1129.0029.5029.45929.822M2.2*0.25 1.95 1.985 1.929规格5/8 - 1113.6012.86813.386PT 1-1/4 -1137.5038.0037.97638.339M2.3*0.25 2.05 2.061 2.001(UNF) 最大最小3/4 - 1016.5018.84016.307PT 1-1/2 -1143.4044.0043.86944.232M2.5*0.35 2.20 2.221 2.1217/8 - 919.5019.76119.177PT 2 -11 54.9055.5055.41255.844 M2.6*0.35 2.20 2.246 2.186No.0-80(1.524) 1.25 1.305 1.182 1 - 822.2022.60621.971M3.0*0.35 2.70 2.721 2.621No.1-72(1.854) 1.55 1.612 1.4741-1/8 - 725.0025.34924.638M3.5*0.35 3.20 3.221 3.121No.2-64(2.184) 1.85 1.912 1.7561-1/4 - 728.2028.52427.813M4.0*0.5 3.50 3.599 3.459No.3-56(2.515) 2.10 2.197 2.0251-3/8 - 630.8031.11530.353M4.5*0.5 4.00 4.099 3.959No.4-48(2.845) 2.40 2.458 2.2711-1/2 - 634.0034.29033.528M5.0*0.5 4.50 4.599 4.459No.5-44(3.175) 2.70 2.740 2.5511-3/4 - 5 39.5039.82738.964M5.5*0.5 5.00 5.099 4.959No.6-40(3.505) 2.90 3.022 2.820 2 - 4-1/245.20 45.593 44.679 使用绞刀时不用绞刀时 M6.0*0.75 5.30 5.378 5.188No.8-36(4.166) 3.50 3.606 3.4041/16 - 27 6.10 6.25M6.0*0.5 5.50 5.550 5.400No.10-32(4.826) 4.10 4.165 3.9631/8 -278.338.43M7.0*0.75 6.30 6.378 6.188No.12-28(5.846) 4.60 4.724 4.4961/4 -1810.7211.13M7.0*0.5 6.50 6.550 6.4001/4 - 28 5.50 5.588 5.3603/8 -1814.2714.27M8.0*1.07.007.153 6.9175/16 - 24 6.907.035 6.782规格1/2 -1417.4817.86M8.0*0.757.307.3787.1883/8 - 248.508.6368.382(UNEF)最大最小3/4 -1422.6323.01M8.0*0.57.507.5207.4007/16 - 209.9010.0339.729No.12 - 32 4.70 4.826 4.623 1 -11-1/228.5828.98M9.0*1.08.008.1537.9171/2 - 2011.5011.60711.3291/4 - 32 5.60 5.690 5.4861-1/4 -11-1/237.3137.69M9.0*0.758.308.3788.1889/16 - 1812.9013.08112.7515/16 - 327.107.2647.0871-1/2 -11-1/243.6644.04M10*1.258.808.9128.4675/8 - 1814.5014.68114.3513/8 - 328.708.8658.661 2 -11-1/2 55.5855.96 M10*1.09.009.1538.9173/4 - 1617.5017.67817.3237/16 - 2810.2010.33810.135M10*0.759.309.3789.1887/8 - 1420.5020.67520.2701/2 - 2811.8011.93811.709M10*0.59.509.5209.400 1 - 1223.2023.57123.1149/16 - 2413.2013.38613.132M11*1.010.0010.1539.9171-1/8 - 1226.5026.74626.2895/8 - 2414.8014.98614.732M11*0.7510.3010.37810.1881-1/4 - 1229.5029.92129.4643/4 - 2017.8017.95817.678M12*1.510.5010.67610.3761-3/8 - 1232.8033.09632.6397/8 - 2021.0021.13320.853M12*1.25 10.80 10.91210.647 1-1/2 - 1236.0 36.271 35.814 1 - 20 24.00 24.30824.028 规 格使用绞刀时不用绞刀时 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 螺 纹 攻 牙 钻 孔 径 和 滚 造 径 对 照 表 英制平行管用螺紋PF(G) (單位：mm) 大 径钻孔径 规格公 制 细 螺 纹 规格 标准径2级牙钻孔径标准径 2级牙钻孔径美 制 特 细 螺 纹 规 格 (螺丝牙外径) 美 制 细 螺 纹 美 制 管 螺 纹 钻 孔 径 标准径 美 制 粗 螺 纹 标准径2级牙钻孔径公 制 粗 螺 纹 公 制 迫 牙 丝 攻 钻 孔 径 规 格精 度 等 级公 制 细 螺 纹 2级牙钻孔径标准径规格14.95 18.6320.5924.12最小6.568.5711.4541.3745.4949.6751.4327.8830.2934.9438.958.49511.341英 制 管 螺 纹 钻孔径 最小规格标准径N P T 14.84623.97530.11138.77218.48944.66556.476 英 制 管 螺 纹 规格18.2623.4229.366.3511.1314.68N P S 44.4556.36 38.108.7457.30 6.490注：迫牙丝攻之钻孔径，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，因此于参考上表之同时，亦请增减若干。 标准径2级牙钻孔径标准径 2级牙钻孔径
建議下孔徑Recommended Tap Drill Sizes ◎公製牙
● ● D1：Minor diameter of JIS Class 2 internal thread. But, the minor diameters D1 shown in ( ) are of JIS Class I internal threads because their nominal sizes are not specified in JIS Class 2. ● * Marked sizes have been eliminated from JIS since 1969. ◎公製牙
● The reccommended tap drill sizes indicated above are for JIS Class 2 Metric threads. ● D1：Minor diameter of JIS Class 2 internal thread. But, the minor diameters D1 shown in ( ) are of JIS Class I internal threads because their nominal sizes are not specified in JIS Class 2. ◎美製牙─ UNC，UNF
● The recommended tap drill sizes indicated above are for JIS Class 2B UNC & UNF threads, and ANSI BI . Ia Class 2B UNEF & UN threads. ● D1：Minor diameter of internal thread. For UNC and UNF threads, according to JIS Class 2B; For UNEF and UN threads, according to ANSI BI . Ia, Class 2B. ◎英製牙─ BSW ● The recommended tap drill sizes indicated above are for JIS Class 2 Whitworth threads. ● Generally, the tap drill sizes in column A are used for producing holes; When holes tend to be cut oversized, the tap drill sizes in column B should be selected. ● These tap drill sizes are in accordance with JIS B 1004-1966, while the nominal sizes with a * mark are in accordance with BSW (Please refer to page 135).
螺丝攻牙钻孔径对照表 美制（粗）挤牙丝攻钻孔径 公制挤牙丝攻钻孔径 美制细牙螺纹 公制细牙螺纹 规格精度max min 规格精度max min 2-56UNC RH4 2.02 1.96M1.0 0.25RH40.920.90最大最小最大最小3-48RH4 2.32 2.25M1.1 0.25RH4 1.02 1.00螺丝牙外径 M7.0 0.50 6.50 6.550 6.4004-40RH5 2.60 2.52M1.2 0.25RH4 1.12 1.10No.0-80（1.524） 1.25 1.305 1.182M8.0 1.00 7.007.153 6.9175-40RH5 2.93 2.86M1.4 0.30RH4 1.294 1.270No.1-72（1.854） 1.55 1.612 1.474M 8.0 0.757.307.3787.1886-32RH5 3.17 3.09M1.6 0.35RH4 1.45 1.40No.2-64（2.184） 1.85 1.912 1.756M8.0 0.507.507.5207.4008-32RH6 3.83 3.75M1.7 0.35RH4 1.58 1.54No.3-56（2.515） 2.10 2.197 2.025M 9.0 1.008.008.1537.91710-24RH6 4.35 4.26M2.0 0.40RH4 1.85 1.81No.4-48（2.845） 2.40 2.458 2.271M9.0 0.758.308.3788.18812-24RH6 5.01 4.92M2.3 0.40RH4 2.15 2.11No.5-44（3.175） 2.70 2.740 2.551M10.0 1.258.808.9128.6471/4-20RH6 5.76 5.66M2.5 0.45RH4 2.33 2.28No.6-40（3.505） 2.90 3.022 2.820M10.0 1.009.009.1538.9175/16-18RH77.297.18M2.6 0.45RH4 2.43 2.38No.8-36（4.166） 3.50 3.606 3.404M10.0 0.759.309.3789.1883/8-16RH78.788.66M3.0 0.50RH5 2.81 2.76No.10-32（4.826） 4.10 4.165 3.963M10.0 0.509.509.5209.4007/16-14RH710.2510.11M3.5 0.60RH5 3.26 3.20No.12-28（5.486） 4.60 4.724 4.496M11.0 1.0010.0010.1539.9171/2-13RH811.7811.62M4.0 0.70RH6 3.70 3.651/4-28 5.50 5.588 5.360M11.0 0.7510.3010.37810.1889/16-12RH1013.2713.14M5.0 0.80RH6 4.66 4.595/16-24 6.907.035 6.782M12.0 1.5010.5010.67610.3765/8-11RH1114.7614.62M6.0 1.00RH7 5.57 5.483/8-248.508.6368.382M12.0 1.2510.8010.91210.6473/4-10RH1217.8817.67M7.0 1.00RH7 6.57 6.487/16-209.9010.0339.729M12.0 1.0011.0011.15310.9177/8-9RH1220.8520.68M8.0 1.00RH77.577.481/2-2011.5011.60711.329M12.0 0.5011.5011.52011.4001-8 RH13 23.84 23.65 M8.0 1.25RH77.417.349/16-1812.9013.08112.751M14.0 1.5012.5012.67612.376M10 1.00RH79.579.485/8-1814.5014.68114.351M14.0 1.0013.0013.15312.917美制（细）挤牙丝攻钻孔径 M10 1.25RH79.419.343/4-1617.5017.67817.323M15.0 1.5013.5013.67613.376规格精度max min M10 1.50RH79.289.187/8-1420.5020.67520.270M15.0 1.0014.0014.15313.9172-64UNF RH3 2.04 1.98M12 1.00RH711.5711.181-12 23.3023.57123.114M16.0 1.5014.5014.67614.3763-56RH4 2.35 2.29M12 1.25RH711.4111.051-1/8-1226.5026.74626.289M16.0 1.0015.0015.15314.9174-48RH4 2.64 2.57M12 1.50RH711.2811.481-1/4-1229.6029.92129.464M17.0 1.5015.5015.67615.3765-44RH4 2.95 2.88M12 1.75RH811.1511.341-3/8-1232.8033.09632.639M17.0 1.0016.0016.15315.9176-40RH5 3.26 3.19M14 1.50RH913.3013.211-1/2-12 36.00 36.271 35.814 M18.0 2.0016.0016.21015.8358-36RH5 3.88 3.80M14 2.00RH1013.0412.92M18.0 1.5016.5016.67616.37610-32RH5 4.48 4.41M16 1.50RH915.3015.21M18.0 1.0017.0017.15316.91712-28RH5 5.08 5.00M16 2.00RH1015.0414.92M20.0 2.0018.0018.21017.8351/4-28RH5 5.93 5.86M18 1.5RH1017.3117.22M20.0 1.5018.5018.67618.3765/16-24RH67.467.38M18 2.5RH1116.7816.63M20.0 1.0019.0019.15318.9173/8-24RH69.058.96M20 1.5RH1019.3119.22M22.0 2.0020.0020.21019.8357/16-20RH710.5410.44M20 2.5 RH11 18.78 18.63 M22.0 1.5020.5020.67620.3761/2-20RH712.1212.02M22.0 1.0021.0021.15320.9179/16-18RH913.6613.55最大最小M24.0 2.0022.0022.21021.8355/8-18RH915.2515.14螺丝牙外径 M24.0 1.5022.5022.67622.3763/4-16RH1018.3218.22 1. 外径-牙距?0.45=下孔＜D-P?0.45＞No.1-64（1.854） 1.55 1.582 1.425M24.0 1.0023.0023.15322.9177/8-14RH1121.3821.27 2. Dn=D-0.2P-0.00403?P?f1+0.0127?n No.2-56（2.184） 1.80 1.871 1.695M25.0 2.0023.0023.21022.8351-12RH12 24.4124.28 ＜例＞M3?0.5RH6 2级母螺纹攻牙 咬合率90%No.3-48（2.515） 2.10 2.146 1.941M25.0 1.5023.5023.67623.376Dn=3-0.2?0.5-0.00403?0.5?90+0.0127?6No.4-40（2.845） 2.30 2.385 2.157M25.0 1.0024.0024.15323.917 =2.80 No.5-40（3.175） 2.60 2.697 2.487M26.0 1.5024.5024.67624.376山数 山数 Dn=下孔径 D=基准外径 P=牙距No.6-32（3.505） 2.80 2.895 2.642M27.0 2.0025.0025.21024.835每25.4mm 每25.4mm f1=咬合率 n=RH 精度 No.8-32（4.166） 3.40 3.530 3.302M27.0 1.5025.5025.67625.3761000.254012 2.1167No.10-24（4.826） 3.90 3.962 3.683M27.0 1.0026.0026.15325.917800.317511 2.3091No.12-24（5.486） 4.50 4.597 4.344M28.0 2.0026.0026.21025.835720.352810 2.54001/4-20 5.10 5.257 4.979M28.0 1.5026.5026.67626.376640.39699 2.82225/16-18 6.60 6.731 6.401M28.0 1.0027.0027.15326.917600.42338 3.17503/8-168.008.1537.798M30.0 3.0027.0027.25226.752560.45367 3.62867/16-149.409.5509.144M30.0 2.0028.0028.21027.835480.52926 4.23331/2-1310.9011.02310.592M30.0 1.5028.5028.67628.376440.57735 5.0800规格吋 mm 9/16-1212.2012.46611.989M30.0 1.0029.0029.15328.917400.63504 1/2 5.6444 No. 0 0.0600 1.5245/8-1113.6013.86813.386M32.0 2.0030.0030.21029.835360.70564 6.350010.0730 1.8543/4-1016.6016.84016.307M32.0 1.5030.5030.67630.376320.79383 1/27.257120.0860 2.1847/8-919.6019.76119.177M33.0 3.0030.0030.25229.752280.90713 1/47.815430.0990 2.5151-8 22.3022.60621.971M33.0 2.0031.0031.21030.83524 1.058338.466740.1120 2.8451-1/8-725.0025.34924.638M33.0 1.5031.5031.67631.37620 1.27002 7/88.834850.1250 3.1751-1/4-728.2028.52427.813M35.0 1.5033.5033.67633.37618 1.41112 3/49.236460.1380 3.5051-3/8-630.8031.11530.353M36.0 3.0033.0033.25232.75216 1.58752 5/89.676280.1640 4.1661-1/2-634.0034.29033.528M36.0 2.0034.0034.21033.83514 1.81432 1/2 10.1600 100.1900 4.8261-3/4-539.5039.82738.964M36.0 1.50 34.50 34.67634.376 13 1.9538 12 0.2160 5.486 2-4-1/2 45.20 45.593 44.679 美制螺丝外径公厘（mm ）换算表 美制粗牙螺纹 规格标准径2级牙钻孔径NRT 下孔径计算式 2级牙钻孔径规格 标准径 2级牙钻孔径牙距mm 牙距mm 规格 标准径 山数节距换算表
螺纹底孔与攻牙后的孔径对照表 以下是常用粗牙公制螺纹钻底孔尺寸对应表。一般情况等于外径-螺距 M1 Φ0.75 M2 Φ1.6 M3 Φ2.5 M4 Φ3.3 M5 Φ4.2 M6 Φ5 M8 Φ6.75 M10 Φ8.5 M12 Φ10.25 M14 Φ12 M16 Φ14 M18 Φ15.5 M20 Φ17.5 M22 Φ19.5 M24 Φ21 M27 Φ24 M30 Φ26.5 螺纹钻孔底径计算 一般按下列公式： 1.攻公制螺纹：螺距t<1毫米，dz=d-t t＞1毫米，dz=d-（1.04～1.06)t 式中t——螺距（毫米） dz——攻丝前钻孔直径（毫米） d——螺纹公称直径（毫米） 2.攻英制螺纹： 螺纹公称直径铸铁与青铜钢与黄铜 3/16"～5/8" dz＝25（d-1/n) dz＝25（d-1/n)+0.1 3/4"～11/2" dz＝25（d-1/n) dz＝25（d-1/n) +0.2 式中dz——攻丝前钻孔直径（毫米） d——螺纹公称直径（英寸） n——每英寸牙数 首先，要知道螺纹的外径D,螺距T,螺纹底孔直径d=D-T。 攻螺纹前钻底孔直径和深度的确定以及孔口的倒角 （1）底孔直径的确定丝锥在攻螺纹的过程中，切削刃主要是切削金属，但还有挤压金属的作用，因而造成金属凸起 并向牙尖流动的现象，所以攻螺纹前，钻削的孔径（即底孔）应大于螺纹内径。 底孔的直径可查手册或按下面的经验公式计算：
脆性材料（铸铁、青铜等）：钻孔直径d0=d(螺纹外径)-1.1p（螺距） 塑性材料（钢、紫铜等）：钻孔直径d0=d(螺纹外径)-p（螺距） （2）钻孔深度的确定攻盲孔（不通孔）的螺纹时，因丝锥不能攻到底，所以孔的深度要大于螺纹的长度， 盲孔的深度可按下面的公式计算： 孔的深度=所需螺纹的深度+0.7d 普通螺纹底孔直径简单计算可按下式 要攻丝的尺寸乘上0.85 如：M3--2.4mm M4--3.1mm M5--4.2m M6--5.1mm M8--6.8mm 公制螺纹的计算方法： 底径=大径-1.0825*螺距 英制螺纹的计算方法： 底径=大径-1.28*螺距 脆性材料钻孔直径D=d(螺纹外径)-1.1p（螺距） 塑性材料钻孔直径D=d(螺纹外径)-p（螺距） 除了以上的经验公司外,还要考虑螺纹的公差等级. 普通公制螺纹用外径-螺距。记这个最直观 螺纹外径计算方法(2009/09/06 19:48) 公制螺纹(MM牙) 牙深=0.6495*牙距P (牙角60度) 内牙孔径= 公称直径-1.0825*P M20x2.5-6H/7g (右手)-(单头螺纹)-(公制粗牙) (公称直径20mm) (牙距2.5mm) (内螺纹配合等级6H) (外螺纹配合等级7g) 左-双头-M20x1.5 (左手)-(双头螺纹)-(公制细牙) (公称直径20mm) (牙距1.5mm) 美制螺纹 (统一标准螺纹) 牙深= 0.6495*(25.4/每吋牙数) (牙角60度) 3/4-10UNC-2A (UNC粗牙)(UNF细牙) (1A 2A 3A 外牙公差配合等级) (1B 2B 3B 内牙公差配合等级)
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 M1.0 M1.1 M1.2 M1.4 M1.6 M1.7 M1.8 M2.0 M2.2 M2.3 M2.5 M2.6 M3.0 M3.0 M3.5 M4.0 M4.0 M4.5 M5.0 M5.0 M6.0 M7.0 最 h < 取小 i 0.785 0.729 NO.1-64(1.854) 1.55 1.582 1.425 i 0.885 0.829 NO.2-56(2.184) 1.80 1.871 1.695 i 0.985 0.985 NO.3-48(2.515)2.10 2.146 1.941 1.142 1.075 NO.4-40( 2.845) 2.30 2.385 2.157 i 1.321 1.221 NO.5-40(3.175) 2.60 2.697 2.487 i 1.421 1.321 NO.6-32(3.505) 2.80 2.895 2.642 i 1.521 1.421 NO8-32(4.166) 3.40 3.53 3.302 1.679 1.567 NO.10-24(4.826) 3.90 3.962 3.683 i 1.838 1.713 NO.12-24(5.486) 4.50 4.597 4.344 1.979 1.867 1/4-20 5.10 5.257 4.979 I 2.138 2.013 5/16-18 6.60 6.731 6.401 I 2.238 2.113 3/8-16 8.00 8.153 7.798 2.599 2.459 ?16-14 9.40 9.55 9.144 2.440 2.280 1/2-13 10.80 11.023 10.592 3.010 2.850 9/16-12 12.20 12.446 11.989 3.422 3.242 ^8-11 13.60 12.868 13.386 i 3.326 3.106 ^4-10 16.50 18.840 16.307 I 3.878 3.688 778-9 19.50 19.761 19.177 4.334 4.134 1 22.20 22.606 21.971 4.170 3.930 1-1/8-7 2 5.00 25.349 24.638 5.153 4.917 1-1/4-7 28.20 28.524 27.813 6.153 5.917 1-3/8-6 30.80 31.115 30.353 0.25 0.75 0.25 0.85 0.25 0.95 0.5 2.50 0.6 2.40 0.6 2.90 0.7 3.30 0.8 4.20 0.9 4.10 1.0 5.00 1.0 6.00 0.3 1.10 0.35 1.25 0.35 1.35 0.35 1.45 0.4 1.60 0.45 1.75 0.4 1.90 0.45 2.10 0.45 2.20 0.75 3.25 0.75 3.80