螺纹尺寸对照表

 公称尺寸和每英寸牙数

 8-32(0.1-32) 10-24(0.190-24) 12-24(0.216-24) 1/4-20(0.250-20) 5/16-18(0.3175-18) 3/8-16(0.375-16) 7/16-14(0.4375-14) 1/2-13(0.50-13)9/16-12(0.5625-12) 5/8-11(0.625-11) 3/4-10(0.750-10) 7/8-9(0.875-9)1\"-8(1.000-8)

螺纹系列代号

大径极限最小0.15713.99030.18184.61770.20785.27810.24086.11630.30267.6860.339.25320.425810.81530.487612.3850.9513.95730.611315.5270.735318.67660.859221.82370.98324.9682

最大0.16314.14270.14.80060.2155.4610.246.32210.31137.9070.37379.4920.436111.07690.498512.66190.560914.24690.623415.83440.748219.00430.873122.17670.99825.3492

中径极限最小0.13993.55350.158.02840.184.68630.21275.40260.27126.88850.32878.3490.3859.7790.443511.290.501612.74060.5514.19610.677317.20340.794620.18280.9123.114

最大0.14283.62710.16194.11230.18794.77270.215.49660.27526.99010.33318.46070.379.840.448511.39190.506812.87270.14.33580.683217.35330.800920.34290.916823.2867

小径max0.12483.16990.13793.50270.16394.16310.187.7650.24316.17470.2977.380.34858.85190.404110.210.458711.6510.511913.00230.625515.88770.736818.71470.844621.4528

UNC

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)

（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

 8-36(0.1-36) 10-32(0.190-32) 12-28

螺纹系列代号

大径极限最小0.15774.00560.18314.65070.2085

最大0.16324.14530.114.80310.215

中径极限最小0.14243.6170.16584.21130.1886

最大0.14523.68810.16884.28750.1918

小径max0.12913.27910.15083.83030.1712

(0.216-28) 1/4-28(0.250-28) 5/16-24(0.3175-24) 3/8-24(0.375-24) 7/16-20(0.4375-20) 1/2-20(0.50-20)9/16-18(0.5625-18) 5/8-18(0.625-18) 3/4-16(0.750-16) 7/8-14(0.875-14)1\"-12(1.000-12)

UNF

5.29590.24256.15950.30427.72670.36679.31420.428110.87370.490612.46120.552414.0310.614915.61850.739118.77310.863121.92270.986825.075.4610.2496.32460.31147.90960.37399.49710.436211.07950.498712.6670.561114.25190.623615.83940.748519.01190.873422.18440.998225.334.79040.22255.65150.28067.12720.3438.71220.399510.14730.461911.73230.520513.22070.582814.80310.702917.85370.821620.86860.938223.83034.87170.22585.73530.28437.22120.34688.80870.403710.20.466211.84150.52513.3350.587514.92250.707917.98070.82721.00580.944123.98014.34850.20525.21210.26036.61160.32288.19910.37499.52250.437411.110.492912.51970.5514.10720.671817.06370.785819.95930.622.7584

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)

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

 8-32(0.1-32) 10-24(0.190-24) 12-24(0.216-24) 1/4-20(0.250-20) 5/16-18(0.3175-18) 3/8-16(0.375-16) 7/16-14(0.4375-14)

螺纹系列代号

小径极限最小0.133.3020.1453.6830.1714.34340.19.97840.2526.40080.3077.79780.369.144

最大0.1393.53060.1563.96240.1814.59740.2075.25780.2656.7310.3218.15340.3769.5504

中径极限最小0.14373.650.16294.13770.184.79810.21755.52450.277.02060.33448.49380.39119.9339

最大0.14753.74650.16724.24690.19334.90980.22245.90.28177.15520.34018.63850.397210.08

大径min0.14.16560.194.8260.2165.480.256.350.31257.93750.3759.5250.437511.1125

UNC

UNC

 1/2-13(0.50-13)9/16-12(0.5625-12) 5/8-11(0.625-11) 3/4-10(0.750-10) 7/8-9(0.875-9)1\"-8(1.000-8)

0.41710.59180.47211.98880.52713.38580.216.30680.75519.1770.86521.971

0.43411.02360.4912.4460.613.86840.66316.84020.77819.76120.22.606

0.4511.430.508412.91340.56614.370.68517.3990.802820.39110.918823.3375

0.456511.59510.515213.08610.573214.55930.692717.59460.81120.59940.927623.561

0.512.70.562514.28750.62515.8750.7519.050.87522.225

125.4

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

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

 8-36(0.1-36) 10-32(0.190-32) 12-28(0.216-28) 1/4-28(0.250-28) 5/16-24(0.3175-24) 3/8-24(0.375-24) 7/16-20(0.4375-20) 1/2-20(0.50-20)9/16-18(0.5625-18) 5/8-18(0.625-18) 3/4-16(0.750-16) 7/8-14

螺纹系列代号

小径极限最小0.1343.40360.1563.96240.1774.49580.2115.35940.2676.78180.338.3820.3839.72820.44611.32840.50212.75080.56514.3510.68217.32280.798

最大0.1423.60680.14.16560.18.72440.225.5880.2777.03580.348.6360.39510.0330.45711.60780.51513.0810.57814.68120.69617.67840.814

中径极限最小0.1463.70840.16974.31040.19284.710.22685.76070.287.24920.34798.83670.40510.2870.467511.87450.5213.37060.5814.95810.709418.01880.8286

最大0.14963.79980.173.40940.1975.00380.23115.86990.29027.37110.35288.96110.410410.42420.473112.01670.532313.52040.594915.11050.715918.18390.8356

大径min0.14.16560.194.8260.2165.480.256.350.31257.93750.3759.5250.437511.1125

0.512.70.562514.28750.62515.8750.7519.050.875

UNF

(0.875-14)1\"-12(1.000-12)20.26920.9123.11420.67560.92823.571221.040.945924.025921.22420.953524.2122.225

125.4

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)

螺胚直径最小3.584.074.725.456.948.49.8311.3412.814.2717.2820.2723.22

最大3.614.14.755.486.988.449.8711.3812.8414.3217.3320.3223.27

螺胚直径最小3.6.244.82

最大3.674.274.85

4.825.697.178.7510.1911.7813.2714.8517.9120.9323.9

4.855.717.28.7810.2311.8213.3114.17.9520.9723.95

底孔直径最小3.43.7.45.056.457.859.2

最大3.53.94.555.26.6.4

10.6512.0513.4516.419.322.1值。

10.912.313.716.719.622.4

底孔直径最小3.44.555.46.858.459.8511.412.8514.4517.420.35

最大3.674.274.855.717.28.7810.2311.8213.3114.17.9520.97

20.3523.9值。

20.9723.95