美国UNF和unc螺纹标准

1、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螺胚直径最小最大最小最大最小最大8-320.15710.16310.13990.14280.1248(0.164-32)3.99034.14273.55353.62713.16993.583.6110-240.18180.18900.15860.16190.1379(0.190-24)4.61774.80064.02844.11233.50274.074.1012-240.20780.21500.18450.18790.1639(0.216-24)UNC5.27815.46104.68634.

2、77274.16314.724.751/4-200.24080.24890.21270.21640.1876(0.250-20)6.11636.32215.40265.49664.76505.455.485/16-180.30260.31130.27120.27520.2431(0.317518)7.68607.90706.88856.99016.17476.946.983/8-160.36430.37370.32870.33310.2970(0.375-16)9.25329.49208.34908.46077.54388.408.447/16-140.42580.43610.38500.38

3、970.3485(0.4375-10.81511.0769.77909.89848.85199.839.8714)391/2-130.48760.49850.44350.44850.404111.311.3(0.50-1312.38512.66111.26411.39110.264148)09999/16-120.54950.56090.50160.50680.458712.812.8(0.5625-13.95714.24612.74012.87211.65100412)39675/8-110.61130.62340.55890.56440.511914.214.3(0.625-115.527

4、15.83414.19614.33513.0023721)04183/4-100.73530.74820.67730.68320.625517.217.3(0.750-118.67619.00417.20317.35315.8877830)63437/8-90.85920.87310.79460.80090.736820.220.3(0.875-921.82322.17620.18220.34218.714772)77891"-80.98300.99800.91000.91680.844623.223.2(1.000-824.96825.34923.11423.28621.45282

5、7)22071.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螺纹系列代号大径极限中径极限小径max螺胚直径最小最大最小最大最小最大8-360.15770.16320.14240.14520.1291(0.164-36)4.00564.14533.61703.68813.27913.653.6710-320.18310.18910.16

6、580.16880.1508(0.190-32)4.65074.80314.21134.28753.83034.244.2712-28UNF0.20850.21500.18860.19180.1712(0.216-28)5.29595.46104.79044.87174.34854.824.851/4-280.24250.24900.22250.22580.2052(0.250-28)6.15956.32465.65155.73535.21215.695.715/16-240.30420.31140.28060.28430.26037.177.20(0.3175-24)7.72677.9096

7、7.12727.22126.61163/8-240.36670.37390.34300.34680.3228(0.375-29.31429.49718.71228.80878.19918.758.784)7/16-200.42810.43620.39950.40370.374910.1(0.4375-10.87311.07910.14710.2549.5225910.2320)75301/2-200.49060.49870.46190.46620.437411.7(0.50-2012.46112.66711.73211.84111.1100811.82)20359/16-180.55240.5

8、6110.52050.52500.492913.2(0.5625-14.03114.25113.22013.33512.5197713.3118)09705/8-180.61490.62360.58280.58750.555414.8(0.625-115.61815.83914.80314.92214.1072514.898)54153/4-160.73910.74850.70290.70790.671817.9(0.750-118.77319.01117.85317.98017.0637117.956)19777/8-140.86310.87340.82160.82700.785820.92

9、0.97(0.875-121.92222.18420.86821.00519.959334)74681"-120.98680.99820.93820.94410.896023.9(1.000-125.06425.35423.83023.98023.9522.758402)73311. 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螺纹系列代号小径极限中径极限大径mi

10、n底孔直径最小最大最小最大最小最大8-320.13000.13900.14370.14750.1640(0.164-32)3.30203.53063.65003.74654.16563.403.5010-240.14500.15600.16290.16720.1900(0.190-24)UNC3.68303.96244.13774.24694.82603.753.9012-240.17100.18100.18890.19330.2160(0.216-24)4.34344.59744.79814.90985.48644.404.551/4-200.19600.20700.2 仃50.22240.

11、2500(0.250-24.97845.25785.52455.64906.35005.055.200)5/16-180.25200.26500.27640.28170.3125(0.3175-6.40086.73107.02067.15527.93756.456.6018)3/8-160.30700.32100.33440.34010.3750(0.375-17.79788.15348.49388.63859.52507.858.006)7/16-140.36000.37600.39110.39720.4375(0.4375-9.14409.55049.933910.08811.11259.

12、209.4014)91/2-130.4 仃00.43400.45000.45650.500010.6(0.50-1310.59111.02311.43011.59512.7000510.90)86019/16-120.47200.49000.50840.51520.562512.0(0.5625-11.98812.44612.91313.08614.2875512.3012)80415/8-110.52700.54600.56600.57320.625013.4(0.625-113.38513.86814.37614.55915.8750513.701)84433/4-100.64200.66

13、300.68500.69270.750016.416.70(0.750-116.30616.84017.39917.59419.050000)82067/8-90.75500.77800.80280.81100.875019.3(0.875-919.17719.76120.39120.59922.2250019.60)02141"-80.86500.89000.91880.92761.000022.1(1.000-821.97122.60623.33723.56125.4000022.40)00501. 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

14、. 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螺纹系列代号小径极限中径极限大径min底孔直径最小最大最小最大最小最大8-360.13400.14200.14600.14960.1640(0.164-33.40363.60683.70843.79984.16563.453.676)UNF10-320.15600.16400.16970.17360.19004.004.27(0.190-33.96244.16564.31044.40944.826

15、02)12-280.仃700.18600.19280.19700.2160(0.216-24.49584.72444.89715.00385.48644.554.858)1/4-280.21100.22000.22680.23110.2500(0.250-25.35945.58805.76075.86996.35005.405.718)5/16-240.26700.27700.28540.29020.3125(0.3175-6.78187.03587.24927.37117.93756.857.2024)3/8-240.33000.34000.34790.35280.3750(0.375-28

16、.38208.63608.83678.96119.52508.458.784)7/16-200.38300.39500.40500.41040.437510.2(0.4375-9.728210.03310.28710.42411.11259.85320)0021/2-200.44600.45700.46750.47310.500011.411.8(0.50-2011.32811.60711.87412.01612.700002)48579/16-180.50200.51500.52640.53230.562512.813.3(0.5625-12.75013.08113.37013.52014.28755118)80645/8-180.56500.57800.58890.59490.625014.414.8(0.625-114.35114.68114.95815.11015.8750598)02153/4-160.68200.69600.70940.71590.750017.417.9(0.750-117.32217.67818.01818.18319.0500056)84897/8-140.79800.81400.82860.83560.