美制螺纹尺寸对照表

最小最大最小最大 8-320.15710.16310.13990.14280.1248(0.164-32) 3.9903 4.1427 3.5535 3.6271 3.1699 10-240.18180.1890.15860.16190.1379(0.190-24) 4.6177 4.8006 4.0284 4.1123 3.5027 12-240.20780.2150.18450.18790.1639(0.216-24) 5.2781 5.461 4.6863 4.7727 4.1631 1/4-200.24080.24890.21270.21640.1876(0.250-20) 6.1163 6.3221 5.4026 5.4966 4.765 5/16-180.30260.31130.27120.27520.2431(0.3175-18)7.6867.907 6.8885 6.9901 6.1747 3/8-160.36430.37370.32870.33310.297(0.375-16)9.25329.4928.3498.46077.5438 7/16-140.42580.43610.3850.38970.3485(0.4375-14)10.815311.07699.7799.89848.8519 1/2-130.48760.49850.44350.44850.4041(0.50-13)12.38512.661911.264911.391910.26419/16-120.54950.56090.50160.50680.4587(0.5625-12)13.957314.246912.740612.872711.651 5/8-110.61130.62340.55890.56440.5119(0.625-11)15.52715.834414.196114.335813.0023 3/4-100.73530.74820.67730.68320.6255(0.750-10)18.676619.004317.203417.353315.8877 7/8-90.85920.87310.79460.80090.7368(0.875-9)21.823722.176720.182820.342918.71471"-80.9830.9980.910.91680.8446(1.000-8)

24.9682

25.3492

23.114

23.2867

21.4528

最小最大最小最大 8-360.15770.16320.14240.14520.1291(0.164-36) 4.0056 4.1453 3.617 3.6881 3.2791 10-320.18310.18910.16580.16880.1508(0.190-32) 4.6507 4.8031 4.2113 4.2875 3.8303 12-28

0.2085

0.215

0.1886

0.1918

0.1712

美制外螺纹（2A）常用规格极限尺寸表（粗牙）

公称尺寸和每英寸牙数螺纹系列

代号

大径极限中径极限小径max 1.螺胚直径指滚丝前的尺寸，数值为依经验公式计算而得，在实践中需验证。

2.标记示例：10-24UNC-2A(或0.190-24UNC-2A)、3/8-16UNC-2A(或0.375-16UNC-2A)

UNC

（注：表中上行斜体数值单位为英寸，下行为毫米）

美制外螺纹（2A）常用规格极限尺寸表（细牙）

公称尺寸和每英寸牙数

螺纹系列代号

大径极限中径极限小径max

(0.216-28) 5.2959 5.461 4.7904 4.8717 4.3485 1/4-280.24250.2490.22250.22580.2052(0.250-28) 6.1595 6.3246 5.6515 5.7353 5.2121 5/16-240.30420.31140.28060.28430.2603(0.3175-24)7.72677.90967.12727.2212 6.6116 3/8-240.36670.37390.3430.34680.3228(0.375-24)9.31429.49718.71228.80878.1991 7/16-200.42810.43620.39950.40370.3749(0.4375-20)10.873711.079510.147310.2549.5225 1/2-200.49060.49870.46190.46620.4374(0.50-20)12.461212.66711.732311.841511.119/16-180.55240.56110.52050.5250.4929(0.5625-18)14.03114.251913.220713.33512.5197 5/8-180.61490.62360.58280.58750.5554(0.625-18)15.618515.839414.803114.922514.1072 3/4-160.73910.74850.70290.70790.6718(0.750-16)18.773119.011917.853717.980717.0637 7/8-140.86310.87340.82160.8270.7858(0.875-14)21.922722.184420.868621.005819.95931"-120.98680.99820.93820.94410.896(1.000-12)

25.064725.354323.830323.980122.7584

最小最大最小最大 8-320.130.1390.14370.14750.164(0.164-32) 3.302 3.5306 3.65 3.7465 4.1656 10-240.1450.1560.16290.16720.19(0.190-24) 3.683 3.9624 4.1377 4.2469 4.826 12-240.1710.1810.18890.19330.216(0.216-24) 4.3434 4.5974 4.7981 4.9098 5.4864 1/4-200.1960.2070.21750.22240.25(0.250-20) 4.9784 5.2578 5.5245 5.649 6.35 5/16-180.2520.2650.27640.28170.3125(0.3175-18) 6.4008 6.7317.02067.15527.9375 3/8-160.3070.3210.33440.34010.375(0.375-16)7.79788.15348.49388.63859.525 7/16-140.360.3760.39110.39720.4375(0.4375-14)

9.144

9.5504

9.9339

10.0889

11.1125

1.螺胚直径指滚丝前的尺寸，数值为依经验公式计算而得，在实践中需验证。

2.标记示例：10-32UNF-2A(或0.190-32UNF-2A)、3/8-24UNF-2A(或0.375-24UNF-2A)

UNF

美制内螺纹（2B）常用规格极限尺寸表（粗牙）

公称尺寸和每英寸牙数

螺纹系列代号

小径极限中径极限大径min UNC

1/2-130.4170.4340.450.45650.5(0.50-13)10.591811.0236

11.4311.595112.79/16-120.4720.490.50840.51520.5625(0.5625-12)11.988812.44612.913413.086114.2875 5/8-110.5270.5460.5660.57320.625(0.625-11)13.385813.868414.376414.559315.875 3/4-100.6420.6630.6850.69270.75(0.750-10)16.306816.840217.39917.594619.05 7/8-90.7550.7780.80280.8110.875(0.875-9)19.17719.7612

20.391120.599422.225

1"-80.8650.890.91880.92761(1.000-8)

21.971

22.606

23.3375

23.561

25.4

最小最大最小最大 8-360.1340.1420.1460.14960.164(0.164-36) 3.4036 3.6068 3.7084 3.7998 4.1656 10-320.1560.1640.16970.17360.19(0.190-32) 3.9624 4.1656 4.3104 4.4094 4.826 12-280.1770.1860.19280.1970.216(0.216-28) 4.4958 4.7244 4.8971 5.0038 5.4864 1/4-280.2110.220.22680.23110.25(0.250-28) 5.3594 5.588 5.7607 5.8699 6.35 5/16-240.2670.2770.28540.29020.3125(0.3175-24) 6.78187.03587.24927.37117.9375 3/8-240.330.340.34790.35280.375(0.375-24)8.3828.6368.83678.96119.525 7/16-200.3830.3950.4050.41040.4375(0.4375-20)9.728210.03310.28710.424211.1125

1/2-200.4460.4570.46750.47310.5(0.50-20)11.328411.607811.874512.016712.79/16-180.5020.5150.52640.53230.5625(0.5625-18)12.750813.08113.370613.520414.2875 5/8-180.5650.5780.58890.59490.625(0.625-18)14.35114.681214.958115.110515.875 3/4-160.6820.6960.70940.71590.75(0.750-16)17.322817.678418.018818.183919.05 7/8-14

0.798

0.814

0.8286

0.8356

0.875

1.底孔直径指攻丝前钻孔直径，铸铁、黄铜等较软料取小值，钢、青铜等较硬料取大值。

2.标记示例：10-24UNC-2B(或0.190-24UNC-2B)、3/8-16UNC-2B(或0.375-16UNC-2B)

UNC

美制内螺纹（2B）常用规格极限尺寸表（细牙）

公称尺寸和每英寸牙数

螺纹系列代号

小径极限中径极限大径min UNF

(0.875-14)20.269220.675621.046421.224222.225

1"-120.910.9280.94590.95351

(1.000-12)23.11423.571224.025924.218925.4

1.底孔直径指攻丝前钻孔直径，铸铁、黄铜等较软料取小值，钢、青铜等较硬料取大值。

2.标记示例：10-32UNF-2B(或0.190-32UNF-2B)、3/8-24UNF-2B(或0.375-24UNF-2B)

最小最大最小最大螺胚直径4.14.72 4.755.45 5.486.94 6.988.48.449.839.8711.3411.3812.812.8414.2714.3217.2817.3320.2720.3223.22

23.27

3.58 3.61

4.07螺胚直径4.274.82

4.85

3.65 3.67

4.24

最小最大4.82 4.855.69 5.717.177.28.758.7810.1910.2311.7811.8213.2713.3114.8514.8917.9117.9520.9320.9723.9

23.95

底孔直径3.94.4 4.555.05 5.26.45 6.67.8589.2

9.4

3.4 3.53.75

最小最大10.6510.912.0512.313.4513.716.416.719.319.622.122.4

值。

底孔直径4.274.55 4.855.4 5.716.857.28.458.789.8510.2311.411.8212.8513.3114.4514.8917.417.9520.35

20.97

3.45 3.674

20.3520.97

23.923.95值。