常用美制螺纹极限尺寸

大径极限 中径极限 螺胚直径公称尺寸和每英寸牙数螺纹系列代号最小最大最小最大小径max 最小 最大8-320.1571 0.1631 0.1399 0.1428 0.1248 (0.164-32)3.99034.1427 3.5535 3.6271 3.1699 3.58 3.61 10-240.1818 0.1890 0.1586 0.1619 0.1379 (0.190-24)4.6177 4.8006 4.0284 4.1123 3.5027 4.07 4.10 12-240.2078 0.2150 0.1845 0.1879 0.1639 (0.216-24)5.2781 5.4610 4.6863 4.7727 4.1631 4.72 4.75 1/4-200.2408 0.2489 0.2127 0.2164 0.1876 (0.250-20)6.1163 6.3221 5.4026 5.4966 4.7650 5.45 5.48 5/16-180.3026 0.3113 0.2712 0.2752 0.2431 (0.3175-18)7.6860 7.9070 6.8885 6.9901 6.1747 6.94 6.98 3/8-160.3643 0.3737 0.3287 0.3331 0.2970 (0.375-16)9.2532 9.4920 8.3490 8.4607 7.5438 8.40 8.44 7/16-140.4258 0.4361 0.3850 0.3897 0.3485 (0.4375-14)10.8153 11.0769 9.77909.8984 8.8519 9.83 9.87 1/2-130.4876 0.4985 0.4435 0.4485 0.4041 (0.50-13)12.3850 12.6619 11.2649 11.3919 10.2641 11.34 11.38 9/16-120.5495 0.5609 0.5016 0.5068 0.4587 (0.5625-12)13.9573 14.2469 12.7406 12.8727 11.6510 12.80 12.84 5/8-110.6113 0.6234 0.5589 0.5644 0.5119 (0.625-11)15.5270 15.8344 14.1961 14.3358 13.0023 14.27 14.32 3/4-100.7353 0.7482 0.6773 0.6832 0.6255 (0.750-10)18.6766 19.0043 17.2034 17.3533 15.8877 17.28 17.33 7/8-90.8592 0.8731 0.7946 0.8009 0.7368 (0.875-9)21.8237 22.1767 20.1828 20.3429 18.7147 20.27 20.32 1"-80.9830 0.99800.9100 0.9168 0.8446 (1.000-8)UNC24.9682 25.3492 23.1140 23.2867 21.452823.22 23.271.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。

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8-32UNC 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 0.1879 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 0.29708.40 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 0.458712.80 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 0.736820.27 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，数值为依经验公式计算而得，在实践中需验证。

美制螺纹标准对照表美制外螺纹（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8-32UNC 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 0.1879 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 0.29708.40 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 0.458712.80 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 0.736820.27 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，数值为依经验公式计算而得，在实践中需验证。

美制螺纹标准对照表美制外螺纹（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8-32UNC 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 0.1879 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 0.29708.40 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 0.458712.80 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 0.736820.27 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，数值为依经验公式计算而得，在实践中需验证。

美制螺丝规格,美制螺丝规格表美制外螺纹（2A ）常用螺丝规格极限尺寸表（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8-32 UNC 0.1571 0.1631 0.1399 0.1428 0.1248 3.58 3.61 (0.164-32) 3.9903 4.1427 3.5535 3.6271 3.169910-24 0.1818 0.1890 0.1586 0.1619 0.1379 4.07 4.10(0.190-24) 4.6177 4.8006 4.0284 4.1123 3.502712-24 0.2078 0.2150 0.1845 0.1879 0.1639 4.72 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 0.1876 5.45 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 0.2431 6.94 6.98(0.3175-18) 7.6860 7.9070 6.8885 6.9901 6.17473/8-160.36430.3737 0.3287 0.3331 0.2970 8.40 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 0.3485 9.83 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 0.4041 11.34 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 0.4587 12.80 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 0.5119 14.27 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 0.6255 17.28 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 0.7368 20.27 20.32(0.875-9) 21.8237 22.1767 20.1828 20.3429 18.71471"-8 0.9830 0.9980 0.9100 0.9168 0.8446 23.22 23.27 (1.000-8) 24.968225.3492 23.1140 23.2867 21.4528美制外螺纹（2A ）常用螺丝规格极限尺寸表（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8-36 UNF 0.1577 0.1632 0.1424 0.1452 0.1291 3.65 3.67 (0.164-36) 4.0056 4.1453 3.6170 3.6881 3.279110-32 0.1831 0.1891 0.1658 0.1688 0.1508 4.24 4.27(0.190-32) 4.6507 4.8031 4.2113 4.2875 3.830312-28 0.2085 0.2150 0.1886 0.1918 0.1712 4.82 4.85(0.216-28) 5.2959 5.4610 4.7904 4.8717 4.34851/4-28 0.2425 0.2490 0.2225 0.2258 0.2052 5.69 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 0.2603 7.17 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 0.3228 8.75 8.78(0.375-24) 9.3142 9.4971 8.7122 8.8087 8.19917/16-20 0.4281 0.4362 0.3995 0.4037 0.3749 10.19 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 0.4374 11.78 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 0.4929 13.27 13.31(0.5625-18) 14.0310 14.2519 13.2207 13.3350 12.51975/8-18 0.6149 0.6236 0.5828 0.5875 0.5554 14.85 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 0.6718 17.91 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 0.7858 20.93 20.97 (0.875-14) 21.9227 22.1844 20.8686 21.0058 19.95931"-120.9868 0.9982 0.9382 0.9441 0.8960 23.90 23.95(1.000-12) 25.064725.3543 23.8303 23.9801 22.7584美制内螺纹（2B ）常用螺丝规格极限尺寸表（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 0.1640 3.40 3.50 (0.164-32) 3.3020 3.5306 3.6500 3.7465 4.165610-24 0.1450 0.1560 0.1629 0.1672 0.1900 3.75 3.90 (0.190-24) 3.6830 3.9624 4.1377 4.2469 4.826012-24 0.1710 0.1810 0.1889 0.1933 0.2160 4.40 4.55(0.216-24) 4.3434 4.5974 4.7981 4.9098 5.48641/4-20 0.1960 0.2070 0.2175 0.2224 0.2500 5.05 5.20 (0.250-20) 4.9784 5.2578 5.5245 5.6490 6.35005/16-18 0.2520 0.2650 0.2764 0.2817 0.3125 6.45 6.60 (0.3175-18) 6.4008 6.7310 7.0206 7.1552 7.93753/8-160.30700.3210 0.3344 0.3401 0.3750 7.85 8.00(0.375-16) 7.7978 8.1534 8.4938 8.6385 9.52507/16-14 0.3600 0.3760 0.3911 0.3972 0.4375 9.20 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 0.5000 10.65 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 0.5625 12.05 12.30 (0.5625-12) 11.9888 12.4460 12.9134 13.0861 14.28755/8-11 0.5270 0.5460 0.5660 0.5732 0.6250 13.45 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 0.7500 16.40 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 0.8750 19.30 19.60(0.875-9) 19.1770 19.7612 20.3911 20.5994 22.22501"-8 0.8650 0.8900 0.9188 0.9276 1.0000 22.10 22.40 (1.000-8) 21.971022.6060 23.3375 23.5610 25.4000美制内螺纹（2B ）常用螺丝规格极限尺寸表（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8-36 UNF 0.1340 0.1420 0.1460 0.1496 0.1640 3.45 3.67 (0.164-36) 3.4036 3.6068 3.7084 3.7998 4.165610-32 0.1560 0.1640 0.1697 0.1736 0.1900 4.00 4.27(0.190-32) 3.9624 4.1656 4.3104 4.4094 4.826012-28 0.1770 0.1860 0.1928 0.1970 0.2160 4.55 4.85(0.216-28) 4.4958 4.7244 4.8971 5.0038 5.48641/4-28 0.2110 0.2200 0.2268 0.2311 0.2500 5.40 5.71(0.250-28) 5.3594 5.5880 5.7607 5.8699 6.35005/16-24 0.2670 0.2770 0.2854 0.2902 0.3125 6.85 7.20(0.3175-24) 6.7818 7.0358 7.2492 7.3711 7.93753/8-24 0.3300 0.3400 0.3479 0.3528 0.3750 8.45 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 0.4375 9.85 10.23(0.4375-20) 9.7282 10.0330 10.2870 10.4242 11.11251/2-20 0.4460 0.4570 0.4675 0.4731 0.5000 11.40 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 0.5625 12.85 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 0.6250 14.45 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 0.7500 17.40 17.95(0.750-16) 17.3228 17.6784 18.0188 18.1839 19.05007/8-14 0.7980 0.8140 0.8286 0.8356 0.8750 20.35 20.97 (0.875-14) 20.2692 20.6756 21.0464 21.2242 22.22501"-12 0.9100 0.9280 0.9459 0.9535 1.0000 23.90 23.95 (1.000-12) 23.1140 23.5712 24.0259 24.2189 25.4000。