美制螺纹标准对照表

1、美制螺纹标准对照表美制螺纹标准对比表美制外螺纹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8-32unc 0.1571 0.1631 0.1399 0.1428 0.12483.58 3.61(0.164-32) 3.9903 4.1427 3.5535 3.6271 3.169910-24 0.1818 0.1890 0.1586 0.1619 0.13794.07 4.10 (0.190-24) 4.6177 4.8006 4.0284 4.1123 3.502712-24 0.2078 0.2150 0.1845 0.1

2、879 0.16394.72 4.75 (0.216-24)5.2781 5.4610 4.6863 4.7727 4.16311/4-20 0.2408 0.2489 0.2127 0.2164 0.18765.45 5.48 (0.250-20)6.1163 6.3221 5.4026 5.4966 4.76505/16-18 0.3026 0.3113 0.2712 0.2752 0.24316.94 6.98 (0.3175-18)7.6860 7.9070 6.8885 6.9901 6.17473/8-16 0.3643 0.3737 0.3287 0.3331 0.29708.4

3、0 8.44 (0.375-16) 9.2532 9.4920 8.3490 8.4607 7.54387/16-14 0.4258 0.4361 0.3850 0.3897 0.34859.83 9.87 (0.4375-14) 10.8153 11.0769 9.7790 9.8984 8.85191/2-13 0.4876 0.4985 0.4435 0.4485 0.404111.34 11.38 (0.50-13) 12.3850 12.6619 11.2649 11.3919 10.26419/16-12 0.5495 0.5609 0.5016 0.5068 0.458712.8

4、0 12.84 (0.5625-12) 13.9573 14.2469 12.7406 12.8727 11.65105/8-11 0.6113 0.6234 0.5589 0.5644 0.511914.27 14.32 (0.625-11) 15.5270 15.8344 14.1961 14.3358 13.00233/4-10 0.7353 0.7482 0.6773 0.6832 0.625517.28 17.33 (0.750-10) 18.6766 19.0043 17.2034 17.3533 15.88777/8-9 0.8592 0.8731 0.7946 0.8009 0

5、.736820.27 20.32 (0.875-9) 21.8237 22.1767 20.1828 20.3429 18.71471"-8 0.9830 0.9980 0.9100 0.9168 0.844623.22 23.27 (1.000-8) 24.9682 25.3492 23.1140 23.2867 21.45281.螺胚直径指滚丝前的尺寸，数值为依阅历公式计算而得，在理论中需验证。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

6、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8-36unf 0.1577 0.1632 0.1424 0.1452 0.12913.65 3.67(0.164-36) 4.0056 4.1453 3.6170 3.6881 3.279110-32 0.1831 0.1891 0.1658 0.1688 0.15084.24 4.27 (0.190-32) 4.6507 4.8031 4.2113 4.2875 3.830312-28 0.2085 0.2150 0.1886 0.1918 0.17124.82 4.85 (0.21

7、6-28)5.2959 5.4610 4.7904 4.8717 4.34851/4-28 0.2425 0.2490 0.2225 0.2258 0.20525.69 5.71 (0.250-28)6.1595 6.3246 5.6515 5.7353 5.21215/16-24 0.3042 0.3114 0.2806 0.2843 0.26037.17 7.20 (0.3175-24) 7.7267 7.9096 7.1272 7.2212 6.61163/8-24 0.3667 0.3739 0.3430 0.3468 0.32288.75 8.78 (0.375-24) 9.3142

8、 9.4971 8.7122 8.8087 8.19917/16-20 0.4281 0.4362 0.3995 0.4037 0.374910.19 10.23 (0.4375-20) 10.8737 11.0795 10.1473 10.2540 9.52251/2-20 0.4906 0.4987 0.4619 0.4662 0.437411.78 11.82 (0.50-20) 12.4612 12.6670 11.7323 11.8415 11.11009/16-18 0.5524 0.5611 0.5205 0.5250 0.492913.27 13.31 (0.5625-18)

9、14.0310 14.2519 13.2207 13.3350 12.51975/8-18 0.6149 0.6236 0.5828 0.5875 0.555414.85 14.89 (0.625-18) 15.6185 15.8394 14.8031 14.9225 14.10723/4-16 0.7391 0.7485 0.7029 0.7079 0.671817.91 17.95 (0.750-16) 18.7731 19.0119 17.8537 17.9807 17.06377/8-14 0.8631 0.8734 0.8216 0.8270 0.785820.93 20.97 (0

10、.875-14) 21.9227 22.1844 20.8686 21.0058 19.95931"-12 0.9868 0.9982 0.9382 0.9441 0.896023.90 23.95 (1.000-12) 25.0647 25.3543 23.8303 23.9801 22.75841.螺胚直径指滚丝前的尺寸，数值为依阅历公式计算而得，在理论中需验证。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小径极限中径极限大径min

11、底孔直径最小最大最小最大最小最大8-32unc 0.1300 0.1390 0.1437 0.1475 0.16403.40 3.50(0.164-32) 3.3020 3.5306 3.6500 3.7465 4.165610-24 0.1450 0.1560 0.1629 0.1672 0.19003.75 3.90 (0.190-24) 3.6830 3.96244.1377 4.2469 4.826012-24 0.1710 0.1810 0.1889 0.1933 0.21604.40 4.55 (0.216-24) 4.3434 4.5974 4.7981 4.90985.4864

12、1/4-20 0.1960 0.2070 0.2175 0.2224 0.25005.05 5.20 (0.250-20) 4.9784 5.2578 5.5245 5.64906.35005/16-18 0.2520 0.2650 0.2764 0.2817 0.31256.45 6.60 (0.3175-18) 6.4008 6.73107.0206 7.1552 7.93753/8-16 0.3070 0.3210 0.3344 0.3401 0.37507.85 8.00 (0.375-16) 7.7978 8.1534 8.4938 8.6385 9.52507/16-14 0.36

13、00 0.3760 0.3911 0.3972 0.43759.20 9.40 (0.4375-14) 9.1440 9.5504 9.9339 10.0889 11.11251/2-13 0.4170 0.4340 0.4500 0.4565 0.500010.65 10.90 (0.50-13) 10.5918 11.0236 11.4300 11.5951 12.70009/16-12 0.4720 0.4900 0.5084 0.5152 0.562512.05 12.30 (0.5625-12) 11.9888 12.4460 12.9134 13.0861 14.28755/8-1

14、1 0.5270 0.5460 0.5660 0.5732 0.625013.45 13.70 (0.625-11) 13.3858 13.8684 14.3764 14.5593 15.87503/4-10 0.6420 0.6630 0.6850 0.6927 0.750016.40 16.70 (0.750-10) 16.3068 16.8402 17.3990 17.5946 19.05007/8-9 0.7550 0.7780 0.8028 0.8110 0.875019.30 19.60 (0.875-9) 19.1770 19.7612 20.3911 20.5994 22.22

15、501"-8 0.8650 0.8900 0.9188 0.9276 1.000022.10 22.40 (1.000-8) 21.9710 22.6060 23.3375 23.5610 25.40001.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螺纹系列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8-36unf 0.1340 0.1420 0.146

16、0 0.1496 0.16403.45 3.67(0.164-36) 3.4036 3.6068 3.7084 3.7998 4.165610-32 0.1560 0.1640 0.1697 0.1736 0.19004.00 4.27 (0.190-32) 3.9624 4.1656 4.3104 4.4094 4.826012-28 0.1770 0.1860 0.1928 0.1970 0.21604.55 4.85 (0.216-28) 4.4958 4.7244 4.89715.0038 5.48641/4-28 0.2110 0.2200 0.2268 0.2311 0.25005

17、.40 5.71 (0.250-28) 5.3594 5.5880 5.7607 5.86996.35005/16-24 0.2670 0.2770 0.2854 0.2902 0.31256.857.20 (0.3175-24) 6.7818 7.0358 7.2492 7.3711 7.93753/8-24 0.3300 0.3400 0.3479 0.3528 0.37508.45 8.78 (0.375-24) 8.3820 8.6360 8.8367 8.9611 9.52507/16-20 0.3830 0.3950 0.4050 0.4104 0.43759.85 10.23 (

18、0.4375-20) 9.7282 10.0330 10.2870 10.4242 11.11251/2-20 0.4460 0.4570 0.4675 0.4731 0.500011.40 11.82 (0.50-20) 11.3284 11.6078 11.8745 12.0167 12.70009/16-18 0.5020 0.5150 0.5264 0.5323 0.562512.85 13.31 (0.5625-18) 12.7508 13.0810 13.3706 13.5204 14.28755/8-18 0.5650 0.5780 0.5889 0.5949 0.625014.45 14.89 (0.625-18) 14.3510 14.6812 14.9581 15.1105 15.87503/4-16 0.6820 0.6960 0.7094 0.7159 0.750017.40 17.95 (0.750-16) 17.