1、美制外螺紋2A常用規格極限尺寸表粗牙公稱尺寸和每英寸牙數螺紋系列代號大徑極限中徑極限小徑max螺胚直徑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)UNC5.27815.46104.68634.7727

2、4.16314.724.751/4-200.24080.24890.21270.21640.1876(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)9.25329.49208.34908.46077.54388.408.447/16-140.42580.43610.38500.38970.

3、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(0.625-115.52715.8

4、3414.19614.33513.0023721)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(1.000-824.96825.34923.11423.28621.452827)22

5、071 .螺胚直徑指滾絲前的尺寸,數值為依經驗公式計算而得,在實踐中需驗證.2 .標記例如：10-24UNC-2A或0.190-24UNC-2A、3/8-16UNC-2A或0.375-16UNC-2A注：表中上行斜體數值單位為英寸,下行為毫米美制外螺紋2A常用規格極限尺寸表細牙公稱尺寸螺紋大徑極限中徑極限螺胚直徑和每英寸牙數系列代號最小最大最小最大小徑max最小最大8-360.15770.16320.14240.14520.1291(0.164-36)4.00564.14533.61703.68813.27913.653.6710-320.18310.18910.16580.16880.150

6、8(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(0.317524)7.72677.90967.12727.22126.

7、61163/8-240.36670.37390.34300.34680.3228(0.375-24)9.31429.49718.71228.80878.19918.758.787/16-20(0.437520)0.428110.87370.436211.07950.399510.14730.403710.25400.37499.522510.1910.231/2-20(0.50-20)0.490612.46120.498712.66700.461911.73230.466211.84150.437411.110011.7811.829/16-18(0.562518)0.552414.03100

8、.561114.25190.520513.22070.525013.33500.492912.519713.2713.315/8-18(0.625-18)0.614915.61850.623615.83940.582814.80310.587514.92250.555414.107214.8514.893/4-16(0.750-16)0.739118.77310.748519.01190.702917.85370.707917.98070.671817.063717.9117.957/8-14(0.875-10.863121.9220.873422.1840.821620.8680.82702

9、1.0050.785819.959320.9320.974)74681"-120.98680.99820.93820.94410.896023.9(1.000-125.06425.35423.83023.98022.7584023.952)73311.螺胚直徑指滾絲前的尺寸,數值為依經驗公式計算而得,在實踐中需驗證.2.標記例如：10-32UNF-2A(或0.190-32UNF-2A)、3/8-24UNF-2A(或0.375-24UNF-2A)美制內螺紋(2B)常用規格極限尺寸表(粗牙)公稱尺寸和每英寸牙數螺紋系列代號小徑極限中徑極限大徑min底孔直徑最小最大最小最大最小最大8-32

10、0.13000.13900.14370.14750.1640(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)4.34344.59744.79814.90985.48644.404.551/4-200.19600.20700.21750.22240.2500(0.250-20)4.97845

11、.25785.52455.64906.35005.055.205/16-180.25200.26500.27640.28170.3125(0.317518)6.40086.73107.02067.15527.93756.456.603/8-160.30700.32100.33440.34010.3750(0.375-16)7.79788.15348.49388.63859.52507.858.007/16-140.36000.37600.39110.39720.4375(0.437514)9.14409.55049.933910.088911.11259.209.401/2-13(0.50-1

12、3)0.417010.59180.434011.02360.450011.43000.456511.59510.500012.700010.6510.909/16-12(0.562512)0.472011.98880.490012.44600.508412.91340.515213.08610.562514.287512.0512.305/8-11(0.625-11)0.527013.38580.546013.86840.566014.37640.573214.55930.625015.875013.4513.703/4-100.64200.66300.68500.69270.750016.4

13、16.70(0.750-10)16.306816.840217.399017.594619.050007/8-9(0.875-9)0.755019.17700.778019.76120.802820.39110.811020.59940.875022.225019.3019.601"-8(1.000-8)0.865021.97100.890022.60600.918823.33750.927623.56101.000025.400022.1022.401.底孔直徑指攻絲前鉆孔直徑,鑄鐵、黃銅等較軟料取小值,鋼、青銅等較硬料取大值.2.標記例如：10-24UNC-2B(或0.190-2

14、4UNC-2B)、3/8-16UNC-2B(或0.375-16UNC-2B)美制內螺紋(2B)常用規格極限尺寸表(細牙)公稱尺寸和每英寸牙數螺紋系列代號小徑極限中徑極限大徑min底孔直徑最小最大最小最大最小最大8-36(0.164-36)UNF0.13403.40360.14203.60680.14603.70840.14963.79980.16404.16563.453.6710-32(0.190-30.15603.96240.16404.16560.16974.31040.17364.40940.19004.82604.004.272)12-280.17700.18600.19280.19

15、700.2160(0.216-28)4.49584.72444.89715.00385.48644.554.851/4-280.21100.22000.22680.23110.2500(0.250-28)5.35945.58805.76075.86996.35005.405.715/16-240.26700.27700.28540.29020.3125(0.317524)6.78187.03587.24927.37117.93756.857.203/8-240.33000.34000.34790.35280.3750(0.375-24)8.38208.63608.83678.96119.525

16、08.458.787/16-20(0.437520)0.38309.72820.395010.03300.405010.28700.410410.42420.437511.11259.8510.231/2-20(0.50-20)0.446011.32840.457011.60780.467511.87450.473112.01670.500012.700011.4011.829/16-18(0.562518)0.502012.75080.515013.08100.526413.37060.532313.52040.562514.287512.8513.315/8-18(0.625-18)0.565014.35100.578014.68120.588914.95810.594915.11050.625015.875014.4514.893/4-16(0.750-16)0.682017.32280.696017.67840.709418.01880.715918.18390.750019.050017.4017.957/8-14(0.875-14)0.798020.2692