各国螺纹底孔直径对照表

各国通用

螺纹底孔直径

一、螺纹底孔直径计算式

螺纹底孔直径可参照表1、表2的公式计算，也可查表3至表11。

表1 加工米制普通螺纹底孔钻头直径D的计算公式 1

D = d – t

式中 d：螺纹的公称直径 t：螺距

适用范围

（1）螺距t<1；

（2）工件材料塑性较大；（3）孔扩张量适中。 （1）螺距t<1；

（2）工件材料塑性较小；（3）孔扩张量较小。

2

D = d – (1.04～1.08)t

表2 加工英制螺纹底孔钻头直径的计算公式

(mm)

螺纹公称直径 (英寸)

铸铁与青铜

钢与黄铜

D = 25.4·(d - 1/n) + 0.1D = 25.4·(d - 1/n) + 0.2

3/16 "～5/8 " D = 25.4·(d - 1/n)3/4 "～1 1/2 " D = 25.4·(d - 1/n)注：n—每英寸牙数

各国通用

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二、螺纹底孔直径表

表3 米制粗牙螺纹攻丝前用的钻头直径(mm)

螺 纹

小 直 径 级 别

公称直径 螺距1 1.2 1.6 2 2.5 3 4 5 6 8 10 12 14 16 18 20 22 24

0.25 0.25 0.35 0.4 0.45 0.5 0.7 0.8 1 1.25 1.5 1.75 2 2 2.5 2.5 2.5 3

5H max 0.7850.9851.3011.6572.1122.5713.3824.2945.0076.8598.61210.37112.13514.13515.64917.64919.64921.152

6H max

7H max

5H、6H、7H

min 0.729 0.929 1.221 1.561 2.013 2.459 3.242 4.134 4.917 6.647 8.376 10.106 11.835 13.835 15.294 17.294 19.294 20.754

钻头直径0.750.951.251.602.052.503.304.205.006.808.5010.212.014.015.517.519.521.0

1.3211.6792.1382.5993.4224.3345.1536.9128.67610.44112.21014.21015.74417.74419.74421.252

2.6393.4664.3845.2176.9828.75110.53112.31014.31015.85417.85419.85421.382

各国通用

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表4 米制细牙螺纹攻丝前用的钻头直径(mm)

螺 纹

小 直 径 级 别

公称直径 螺距 2.5 3 4 5 6 8 10 8 10 12 14 16 18 20 22 24 10 12 14 12 14 15 16 18 20 22

5H max 2.201

0.35

2.701 3.571

0.5

4.571 5.338

0.75 7.338

9.338 7.107 9.107 11.10713.10715.1071

17.10719.10721.10723.1078.859

1.25 10.859

12.85910.61212.61213.612

1.5 14.612

16.61218.61220.612

6H max 2.221 2.721 3.599 4.599 5.378 7.378 9.378 7.217 9.217 11.21713.21715.21717.21719.21721.21723.2178.912 10.91212.91210.67612.67613.67614.67616.67618.67620.676

7H max 3.639 4.639 5.424 7.424 9.424 7.217 9.217 11.21713.21715.21717.21719.21721.21723.2178.982 10.98212.98210.75112.75113.75114.75116.75118.75120.751

5H、6H、7H

min 2.121 2.621 3.459 4.459 5.188 7.188 9.188 6.917 8.917 10.917 12.917 14.917 16.917 18.917 20.917 22.917 8.647 10.647 12.647 10.376 12.376 13.376 14.376 16.376 18.376 20.376

钻头直径2.152.653.504.505.707.209.207.009.0011.013.015.017.019.021.023.08.8010.812.810.512.513.514.516.518.520.5

各国通用

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螺 纹

小 直 径 级 别

公称直径 螺距 24 25 18 20 22 24 25

5H max 22.61223.61216.13518.13520.13522.13523.135

6H max 22.67623.67616.21018.21020.21022.21023.210

7H max 22.75123.75116.31018.31020.31022.31023.310

5H、6H、7H

min 22.376 23.376 15.835 17.835 19.835 21.835 22.835

钻头直径22.523.516.018.020.022.023.0

1.5

2

表5 英国标准粗牙惠氏螺纹 Ｂ、Ｓ、Ｗ攻丝前用的钻头直径(mm)

公称直径 （英寸） 3/16 1/4 5/16 3/8 1/2 5/8 3/4 7/8 1 1 1/8 1 1/4 1 1/2 1 3/4 2

每英寸牙数

24 20 18 16 12 11 10 9 8 7 7 6 5 4 1/2

钻 头 直 径

铸铁、青铜、黄铜

3.8 5.1 6.6 8.0 10.6 13.6 16.6 19.6 22.3 25.0 28.2 34.0 39.5 45.3

钢、可锻铸铁

3.9 5.2 6.7 8.1 10.7 13.8 16.8 19.7 22.5 25.2 28.4 34.2 39.7 45.6

各国通用

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表6 英寸制统一粗牙螺纹UNC攻丝前用的钻头直径(mm)

螺 纹

公称直径 每英寸（英寸） 牙 数No.1 No.2 No.3 No.4 No.5 No.6 No.8 No.10 No.12 1/4 5/16 3/8 7/16 1/2 9/16 5/8 3/4 7/8 1 1 1/8 1 1/4 1 3/8 1 1/2 1 3/4 2

64 56 48 40 40 32 32 24 24 20 18 16 14 13 12 11 10 9 8 7 7 6 6 5 4 1/2

小 直 径 级 别

螺 距0.397 0.454 0.529 0.635 0.635 0.794 0.794 1.058 1.058 1.270 1.411 1.588 1.814 1.954 2.117 2.309 2.540 2.822 3.175 3.629 3.629 4.233 4.233 5.080 5.644

2B max 1.5821.8722.1462.3852.6972.8963.5313.9624.5975.2686.7848.1649.55011.01312.45613.86816.83319.74822.59825.34928.52431.12034.29539.81445.598

3B max 1.5821.8722.1462.3852.6972.8963.5283.9504.5905.2506.6808.0829.44110.88112.30113.69316.62419.52022.34425.08228.25830.85134.02639.56045.367

2B、3Bmin 1.4251.6941.9412.1562.4872.6423.3023.6834.3434.9766.4117.8059.14910.58411.99613.37616.29919.16921.96324.64827.82330.34333.51938.95144.689

钻头 直径 1.55 1.85 2.10 2.35 2.65 2.85 3.50 3.90 4.60 5.10 6.60 8.00 9.40 10.80 12.20 13.50 16.50 19.50 22.25 25.00 28.00 30.75 34.00 39.50 45.00

各国通用

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表7 英寸制统一细牙螺纹UNF攻丝前用的钻头直径(mm)

螺 纹

公称直径 每英寸（英寸） 牙 数No.0 No.1 No.2 No.3 No.4 No.5 No.6 No.8 No.10 No.12 1/4 5/16 3/8 7/16 1/2 9/16 5/8 3/4 7/8 1 1 1/8 1 1/4 1 3/8 1 1/2

80 72 64 56 48 44 40 36 32 28 28 24 24 20 20 18 18 16 14 12 12 12 12 12

小 直 径 级 别

螺 距0.318 0.353 0.397 0.454 0.529 0.577 0.635 0.706 0.794 0.907 0.907 1.058 1.058 1.270 1.270 1.411 1.411 1.588 1.814 2.117 2.117 2.117 2.117 2.117

2B max 1.3061.6131.9132.1972.4592.7413.0233.6074.1664.7245.5807.0388.62610.03011.61813.08414.67117.68920.66323.56926.74429.91933.09436.269

3B max 1.3061.6131.9132.1972.4592.7413.0123.5974.1684.7175.5636.9958.5659.94711.52412.96914.55417.54620.49323.36326.53829.71332.88836.063

2B、3Bmin 1.1811.4731.7552.0242.2712.5502.8193.4043.9624.4965.3676.7928.3799.73811.32612.76114.34817.33020.26223.10926.28429.45932.63435.809

钻头 直径 1.25 1.55 1.90 2.15 2.40 2.70 2.95 3.50 4.10 4.70 5.50 6.90 8.50 9.90 11.50 12.90 14.50 17.50 20.40 23.25 26.50 29.50 32.75 36.00

各国通用

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表8 GB7307-87、ISO228/1-1982非螺纹密封的管螺纹

攻丝前用的钻头直径(mm)

螺 纹

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