ISO Screw Threads Metric
Limiting Dimensions of Standard Series Threads for Commercial Screws, Bolts and Nuts (Inches)
Nom- inal Size Diam
External Thread (Bolt)
Internal Thread (Nut)
Basic Thread Desig- nation
Pitch P
Major Diameter
Minor Diameter Tol Cl.
Minor Diameter
Major Dia.
Pitch Diameter
Pitch Diameter
Tol Cl.
Allow- ance
mm mm
Max.
Min.
Max.
Min.
Tol.
Max.
Min.
Min.
Max.
Min.
Max.
Tol.
Min.
1.6 0.35 M1.6 6g 0.0008 0.0622 0.0589 0.0533 0.0509 0.0024 0.0453 0.0419 6H 0.0481 0.0520 0.0541 0.0574 0.0033 0.0630 1.8 0.35 M1.8 6g 0.0008 0.0701 0.0668 0.0611 0.0588 0.0023 0.0531 0.0498 6H 0.0560 0.0598 0.0620 0.0652 0.0032 0.0709 2 0.4 M2.0 6g 0.0009 0.0779 0.0743 0.0677 0.0652 0.0025 0.0586 0.0549 6H 0.0617 0.0661 0.0686 0.0720 0.0034 0.0788 2.2 0.45 M2.2 6g 0.0009 0.0858 0.0819 0.0743 0.0716 0.0027 0.0640 0.0601 6H 0.0675 0.0723 0.0752 0.0788 0.0036 0.0867 2.5 0.45 M2.5 6g 0.0009 0.0976 0.0938 0.0861 0.0834 0.0027 0.0759 0.0719 6H 0.0793 0.0841 0.0870 0.0906 0.0036 0.0985 3 0.5 M3.0 6g 0.0009 0.1173 0.1132 0.1045 0.1016 0.0029 0.0931 0.0889 6H 0.0969 0.1023 0.1054 0.1092 0.0038 0.1182 3.5 0.6 M3.5 6g 0.0009 0.1369 0.1321 0.1216 0.1183 0.0033 0.1079 0.1030 6H 0.1123 0.1185 0.1225 0.1268 0.0043 0.1378 4 0.7 M4.0 6g 0.0009 0.1566 0.1512 0.1387 0.1352 0.0034 0.1227 0.1173 6H 0.1277 0.1347 0.1396 0.1442 0.0046 0.1575 4.5 0.75 M4.5 6g 0.0010 0.1762 0.1708 0.1571 0.1536 0.0035 0.1400 0.1345 6H 0.1452 0.1526 0.1580 0.1626 0.0046 0.1772 5 0.8 M5.0 6g 0.0010 0.1959 0.1900 0.1754 0.1717 0.0037 0.1572 0.1513 6H 0.1628 0.1706 0.1764 0.1812 0.0048 0.1969 6 1.0 M6.0 6g 0.0012 0.2351 0.2282 0.2096 0.2052 0.0044 0.1868 0.1797 6H 0.1936 0.2028 0.2107 0.2165 0.0058 0.2363 7 1.0 M7.0 6g 0.0011 0.2745 0.2675 0.2489 0.2446 0.0043 0.2262 0.2191 6H 0.2330 0.2422 0.2501 0.2559 0.0058 0.2756 8 1.25 M8.0 6g 0.0012 0.3138 0.3056 0.2818 0.2773 0.0045 0.2535 0.2454 6H 0.2617 0.2721 0.2830 0.2892 0.0062 0.3150 8 1.0 M8 x 1.0 6g 0.0011 0.3139 0.3069 0.2883 0.2840 0.0043 0.2656 0.2584 6H 0.2724 0.2816 0.2894 0.2952 0.0058 0.3150 10 1.5 M10 6g 0.0013 0.3924 0.3832 0.3540 0.3489 0.0051 0.3199 0.3102 6H 0.3298 0.3415 0.3554 0.3624 0.0070 0.3937 10 1.25 M10 x 1.25 6g 0.0012 0.3925 0.3843 0.3606 0.3560 0.0046 0.3322 0.3241 6H 0.3404 0.3508 0.3618 0.3680 0.0062 0.3937 12 1.75 M12 6g 0.0014 0.4711 0.4607 0.4263 0.4205 0.0058 0.3865 0.3758 6H 0.3979 0.4110 0.4277 0.4355 0.0078 0.4725 12 1.25 M12 x 1.25 6g 0.0012 0.4713 0.4630 0.4393 0.4342 0.0051 0.4109 0.4023 6H 0.4192 0.4295 0.4405 0.4475 0.0070 0.4725 14 2.0 M14 6g 0.0016 0.5496 0.5387 0.4985 0.4923 0.0062 0.4530 0.4412 6H 0.4660 0.4807 0.5001 0.5083 0.0082 0.5512 14 1.5 M14 x 1.5 6g 0.0013 0.5499 0.5407 0.5115 0.5061 0.0054 0.4774 0.4677 6H 0.4873 0.4990 0.5129 0.5203 0.0074 0.5512 16 2.0 M16 6g 0.0016 0.6284 0.6175 0.5772 0.5710 0.0062 0.5318 0.5199 6H 0.5447 0.5594 0.5788 0.5871 0.0083 0.6300 16 1.5 M16 x 1.5 6g 0.0014 0.6286 0.6194 0.5903 0.5849 0.0054 0.5561 0.5465 6H 0.5660 0.5777 0.5916 0.5990 0.0074 0.6300 18 2.5 M18 6g 0.0017 0.7070 0.6939 0.6430 0.6364 0.0066 0.5862 0.5725 6H 0.6022 0.6198 0.6448 0.6535 0.0087 0.7087 18 1.5 M18 x 1.5 6g 0.0013 0.7074 0.6982 0.6690 0.6636 0.0054 0.6349 0.6252 6H 0.6448 0.6565 0.6704 0.6777 0.0073 0.7087 20 2.5 M20 6g 0.0018 0.7857 0.7726 0.7218 0.7152 0.0066 0.6649 0.6513 6H 0.6809 0.6985 0.7235 0.7322 0.0087 0.7875 20 1.5 M20 x 1.5 6g 0.0014 0.7861 0.7769 0.7477 0.7423 0.0054 0.7136 0.7039 6H 0.7235 0.7352 0.7491 0.7565 0.0074 0.7875 22 2.5 M22 6g 0.0018 0.8644 0.8513 0.8005 0.7939 0.0066 0.7437 0.7300 6H 0.7597 0.7773 0.8023 0.8110 0.0087 0.8662 22 1.5 M22 x 1.5 6g 0.0014 0.8648 0.8556 0.8265 0.8211 0.0054 0.7924 0.7827 6H 0.8023 0.8140 0.8278 0.8352 0.0074 0.8662 24 3.0 M24 6g 0.0020 0.9429 0.9283 0.8662 0.8584 0.0078 0.7980 0.7817 6H 0.8171 0.8366 0.8682 0.8785 0.0103 0.9449 24 2.0 M24 x 2.0 6g 0.0016 0.9433 0.9324 0.8922 0.8856 0.0066 0.8467 0.8345 6H 0.8597 0.8744 0.8938 0.9025 0.0087 0.9449 27 3.0 M27 6g 0.0019 1.0611 1.0464 0.9843 0.9765 0.0078 0.9161 0.8999 6H 0.9352 0.9548 0.9863 0.9966 0.0103 1.0630 27 2.0 M27 x 2.0 6g 0.0016 1.0614 1.0505 1.0103 1.0037 0.0066 0.9648 0.9526 6H 0.9778 0.9925 1.0119 1.0206 0.0087 1.0630 30 3.5 M30 6g 0.0022 1.1790 1.1623 1.0895 1.0812 0.0083 1.0099 0.9917 6H 1.0320 1.0539 1.0917 1.1026 0.0109 1.1812 30 2.0 M30 x 2.0 6g 0.0016 1.1796 1.1686 1.1284 1.1218 0.0066 1.0829 1.0707 6H 1.0959 1.1106 1.1300 1.1387 0.0087 1.1812 33 3.5 M33 6g 0.0022 1.2971 1.2804 1.2076 1.1993 0.0083 1.1280 1.1099 6H 1.1501 1.1720 1.2098 1.2207 0.0109 1.2993 33 2.0 M33 x 2.0 6g 0.0016 1.2977 1.2867 1.2465 1.2399 0.0066 1.2011 1.1888 6H 1.2140 1.2287 1.2481 1.2568 0.0087 1.2993 36 4.0 M36 6g 0.0025 1.4149 1.3963 1.3126 1.3039 0.0087 1.2217 1.2017 6H 1.2469 1.2704 1.3151 1.3268 0.0117 1.4174 36 3.0 M36 x 3.0 6g 0.0020 1.4154 1.4007 1.3386 1.3309 0.0077 1.2705 1.2542 6H 1.2895 1.3091 1.3406 1.3510 0.0104 1.4174 39 4.0 M39 6g 0.0025 1.5330 1.5144 1.4307 1.4220 0.0087 1.3398 1.3198 6H 1.3650 1.3885 1.4332 1.4449 0.0117 1.5355 39 3.0 M39 x 3.0 6g 0.0020 1.5335 1.5188 1.4568 1.4490 0.0078 1.3886 1.3723 6H 1.4076 1.4272 1.4587 1.4691 0.0104 1.5355 Excerpt from American National Standard B1. 16-1972, American Gaging Practices for Metric Screw Threads; “In all cases the inch conversion values have been rounded toward the interior of the tolerance zone, that is, maximum limits have been rounded downward and minimum limits have been rounded upward. Due to the fact that the majority of machinery and measuring equipment in the United States is based on the inch system, all gages should be made to the inch conversions.” TAP RECOMMENDATIONS: The pitch diameter high limits of the recommended tap for 6H tolerance class is 40% of the product tolerance rounded to the nearest 0.0005.” Example: M10 x 1.5; product tolerance = 0.00070” x .40 = .0028” rounded to 0.0030”. This is the amount over basic pitch diameter. Based on 0.0005” increments over basic pitch diameter, the recommended tap has a D6 high limit (0.0030 ÷ 0.0005”).
Threading Technical
775
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