Internal Threads - Class 2B
| Nominal
Size & Threads / Inch & Series Designation |
Allow- ance |
Minor Diameter |
Pitch Diameter |
Major Diameter |
||||
| Min. | Max. | Min. | Max. | Tolerance | Min. | |||
| 0-80 1-64 1-72 2-56 2-64 |
UNF UNC UNF UNC UNF |
0.0005 0.0006 0.0006 0.0006 0.0006 |
0.0465 0.0561 0.0580 0.0667 0.0691 |
0.0514 0.0623 0.0635 0.0737 0.0753 |
0.0519 0.0629 0.0640 0.0744 0.0759 |
0.0542 0.0655 0.0665 0.0772 0.0786 |
0.0023 0.0026 0.0025 0.0028 0.0027 |
0.0600 0.0730 0.0730 0.0860 0.0860 |
| 3-48 3-56 4-40 4-48 5-40 |
UNC UNF UNC UNF UNC |
0.0007 0.0007 0.0008 0.0007 0.0008 |
0.0764 0.0797 0.0849 0.0894 0.0979 |
0.0845 0.0865 0.0939 0.0968 0.1062 |
0.0855 0.0874 0.0958 0.0985 0.1088 |
0.0885 0.0902 0.0991 0.1016 0.1121 |
0.0030 0.0028 0.0033 0.0031 0.0033 |
0.0990 0.0990 0.1120 0.1120 0.1250 |
| 5-44 6-32 6-40 8-32 8-36 |
UNF UNC UNF UNC UNF |
0.0007 0.0008 0.0008 0.0009 0.0008 |
0.1004 0.104 0.111 0.130 0.134 |
0.1079 0.114 0.119 0.139 0.142 |
0.1102 0.1177 0.1218 0.1437 0.1460 |
0.1134 0.1214 0.1252 0.1475 0.1496 |
0.0032 0.0037 0.0034 0.0038 0.0036 |
0.1250 0.1380 0.1380 0.1640 0.1640 |
| 10-24 10-32 12-24 12-28 1/4-20 |
UNC UNF UNC UNF UNC |
0.0010 0.0009 0.0010 0.0010 0.0011 |
0.145 0.156 0.171 0.177 0.196 |
0.156 0.164 0.181 0.186 0.207 |
0.1629 0.1697 0.1889 0.1928 0.2175 |
0.1672 0.1736 0.1933 0.1970 0.2224 |
0.0043 0.0039 0.0044 0.0042 0.0049 |
0.1900 0.1900 0.2160 0.2160 0.2500 |
| 1/4-28 5/16-18 5/16-24 3/8-16 3/8-24 |
UNF UNC UNF UNC UNF |
0.0010 0.0012 0.0011 0.0013 0.0011 |
0.211 0.252 0.267 0.307 0.330 |
0.220 0.265 0.277 0.321 0.034 |
0.2268 0.2764 0.2854 0.3344 0.3479 |
0.2311 0.2817 0.2902 0.3401 0.3528 |
0.0043 0.0053 0.0048 0.0057 0.0049 |
0.2500 0.3125 0.3125 0.3750 0.3750 |
| 7/16-14 7/16-20 1/2-13 1/2-20 9/16-12 |
UNC UNF UNC UNF UNC |
0.0014 0.0013 0.0015 0.0013 0.0016 |
0.360 0.383 0.417 0.446 0.472 |
0.376 0.395 0.434 0.457 0.490 |
0.3911 0.4050 0.4500 0.4675 0.5084 |
0.3972 0.4104 0.4565 0.4731 0.5152 |
0.0061 0.0054 0.0065 0.0056 0.0068 |
0.4375 0.4375 0.5000 0.5000 0.5625 |
| 9/16-18 5/8-11 5/8-18 3/4-10 3/4-16 |
UNF UNC UNF UNC UNF |
0.0014 0.0016 0.0014 0.0018 0.0015 |
0.502 0.527 0.565 0.642 0.682 |
0.515 0.546 0.578 0.663 0.696 |
0.5264 0.5660 0.5889 0.6850 0.7094 |
0.5323 0.5732 0.5949 0.6927 0.7159 |
0.0059 0.0072 0.0060 0.0077 0.0065 |
0.5625 0.6250 0.6250 0.7500 0.7500 |
| 7/8-9 7/8-14 1-8 1-12 1-14 |
UNC UNF UNC UNF UNS |
0.0019 0.0016 0.0020 0.0018 0.0017 |
0.755 0.798 0.865 0.910 0.923 |
0.778 0.814 0.890 0.928 0.938 |
0.8028 0.8286 0.9188 0.9459 0.9536 |
0.8110 0.8356 0.9276 0.9535 0.9609 |
0.0082 0.0070 0.0088 0.0076 0.0073 |
0.8750 0.8750 1.0000 1.0000 1.0000 |
| 11/8-7 11/8-8 11/812 11/4-7 11/4-8 |
UNC UN UNF UNC UN |
0.0022 0.0021 0.0018 0.022 0.0021 |
0.970 0.990 1.035 1.095 1.115 |
0.998 1.015 1.053 1.123 1.140 |
1.322 1.0438 1.0709 1.1572 1.1688 |
1.0416 0.0528 1.0787 1.668 1.1780 |
0.0094 0.0090 0.0078 0.0096 0.0092 |
1.1250 1.1250 1.1250 1.2500 1.2500 |
| 11/4-12 1 3/8-6 1 3/8-8 1 3/8-12 11/2-6 |
UNF UNC UN UNF UNC |
0.0018 0.0024 0.0022 0.0019 0.0024 |
1.160 1.195 1.240 1.285 1.320 |
1.178 1.225 1.265 1.303 1.350 |
1.1959 1.2667 1.2938 1.3209 1.3917 |
1.2039 1.2771 1.3031 1.3291 1.4022 |
0.0080 0.0104 0.0093 0.0082 0.0105 |
1.2500 1.3750 1.3750 1.3750 1.5000 |
| 11/2-8 11/2-12 1 5/8-8 1 3/4-5 1 3/4-8 |
UN UNC UN UNC UN |
0.0022 0.0019 0.0022 0.0027 0.0023 |
1.365 1.410 1.490 1.534 1.615 |
1.390 1.428 1.515 1.568 1.640 |
1.4188 1.4459 1.5438 1.6201 1.6688 |
1.4283 1.4542 1.5535 1.6317 1.6786 |
0.0095 0.0083 0.0097 0.0116 0.0098 |
1.5000 1.5000 1.6250 1.7500 1.7500 |
| 1 7/8-8 2-41/2 2-8 2 1/4-4.5 2 1/4-8 |
UN UNC UN UNC UN |
0.0023 0.0029 0.0023 0.0029 0.0024 |
1.740 1.759 1.865 2.009 2.115 |
1.765 1.795 1.890 2.045 2.140 |
1.7938 1.8557 1.9188 2.1057 2.1688 |
1.8038 1.8681 1.9289 2.1183 2.1792 |
0.0100 0.0124 0.0101 0.0126 0.0104 |
1.8750 2.0000 2.0000 2.2500 2.2500 |
| 2 1/2-4 2 1/2-8 2 3/4-4 2 3/4-8 3-4 |
UNC UN UNC UN UNC |
0.0031 0.0024 0.0032 0.0025 0.0032 |
2.229 2.365 2.479 2.615 2.729 |
2.267 2.390 2.517 2.640 2.767 |
2.3376 2.4188 2.5876 2.6688 2.8376 |
2.3511 2.4294 2.6013 2.6796 2.8515 |
0.0135 0.0106 0.0137 0.0108 0.0139 |
2.5000 2.5000 2.7500 2.7500 3.0000 |
| 3-8 3 1/4-4 31/4-8 3 1/2-4 31/2-8 |
UN UNC UN UNC UN |
0.0026 0.0033 0.0026 0.0033 0.0026 |
2.865 2.979 3.115 3.229 3.365 |
2.890 3.017 3.140 3.267 3.390 |
2.9188 3.0876 3.1688 3.3376 3.4188 |
2.9299 3.1017 3.1801 3.3519 3.4303 |
0.0111 0.0141 0.0113 0.0143 0.0115 |
3.0000 3.2500 3.2500 3.5000 3.5000 |
| 3 3/4-4 3 3/4-8 4-4 4-8 |
UNC UN UNC UN |
0.0034 0.0027 0.0034 0.0027 |
3.479 3.615 3.729 3.865 |
3.517 3.640 3.767 3.890 |
3.5876 3.6688 3.8376 3.9188 |
3.6021 3.6805 3.8523 3.9307 |
0.0145 0.0117 0.0147 0.0119 |
3.7500 3.7500 4.0000 4.0000 |
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