Standard Thread Pitches
Standard Thread Pitches
| Coarse Thread Series - UNC | Fine Thread Series - UNF | 8-Thread Series - 8UN | |||||||||
| Nominal Size and Threads Per In. | Basic Pitch Dia. | Section at Minor Dia. | Tensile Stress Area | Nominal Size and Threads Per In. | Basic Pitch Dia. | Section at Minor Dia. | Tensile Stress Area | Nominal Size and Threads Per In. | Basic Pitch Dia. | Section at Minor Dia. | Tensile Stress Area |
| In. | Sq in. | Sq in. | In. | Sq in. | Sq in. | In. | Sq in. | Sq in. | |||
| -- -- | -- | -- | -- | 0 - 80 | 0.0519 | 0.00151 | 0.00180 | -- -- | -- | -- | -- |
| 1 - 64 | 0.0629 | 0.00218 | 0.00263 | 1 - 72 | 0.0640 | 0.00237 | 0.00278 | ||||
| 2 - 56 | 0.0744 | 0.00310 | 0.00370 | 2 - 64 | 0.0759 | 0.00339 | 0.00394 | ||||
| 3 - 48 | 0.0855 | 0.00406 | 0.00487 | 3 - 56 | 0.0874 | 0.00451 | 0.00523 | ||||
| 4 - 40 | 0.0958 | 0.00496 | 0.00604 | 4 - 48 | 0.0985 | 0.00566 | 0.00661 | -- -- | -- | -- | -- |
| 5 - 40 | 0.1088 | 0.00672 | 0.00796 | 5 - 44 | 0.1102 | 0.00716 | 0.00830 | ||||
| 6 - 32 | 0.1177 | 0.00745 | 0.00909 | 6 - 40 | 0.1218 | 0.00874 | 0.01015 | ||||
| 8 - 32 | 0.1437 | 0.01196 | 0.0140 | 8 - 36 | 0.1460 | 0.01285 | 0.01474 | ||||
| 10 - 24 | 0.1629 | 0.01450 | 0.0175 | 10 - 32 | 0.1697 | 0.0175 | 0.0200 | -- -- | -- | -- | -- |
| 12 - 24 | 0.1889 | 0.0206 | 0.0242 | 12 - 28 | 0.1928 | 0.0226 | 0.0258 | -- -- | -- | -- | -- |
| 1/4 - 20 | 0.2175 | 0.0269 | 0.0318 | 1/4 - 28 | 0.2268 | 0.0326 | 0.0364 | -- -- | -- | -- | -- |
| 5/16 - 18 | 0.2764 | 0.0454 | 0.0524 | 5/16 - 24 | 0.2854 | 0.0524 | 0.0580 | -- -- | -- | -- | -- |
| 3/8 - 16 | 0.3344 | 0.0678 | 0.0775 | 3/8 - 24 | 0.3479 | 0.0809 | 0.0878 | -- -- | -- | -- | -- |
| 7/16 - 14 | 0.3911 | 0.0933 | 0.1063 | 7/16 - 20 | 0.4050 | 0.1090 | 0.1187 | -- -- | -- | -- | -- |
| 1/2 - 13 | 0.4500 | 0.1257 | 0.1419 | 1/2 - 20 | 0.4675 | 0.1486 | 0.1599 | -- -- | -- | -- | -- |
| 9/16 - 12 | 0.5084 | 0.162 | 0.182 | 9/16 - 18 | 0.5264 | 0.189 | 0.203 | -- -- | -- | -- | -- |
| 5/8 - 11 | 0.5660 | 0.202 | 0.226 | 5/8 - 18 | 0.5889 | 0.240 | 0.256 | -- -- | -- | -- | -- |
| 3/4 - 10 | 0.6850 | 0.302 | 0.334 | 3/4 - 16 | 0.7094 | 0.351 | 0.373 | -- -- | -- | -- | -- |
| 7/8 - 9 | 0.8028 | 0.419 | 0.462 | 7/8 - 14 | 0.8286 | 0.180 | 0.509 | -- -- | -- | -- | -- |
| 1 - 8 | 0.9188 | 0.551 | 0.606 | 1 - 12 | 0.9459 | 0.625 | 0.663 | 1 - 8 | 0.9188 | 0.551 | 0.606 |
| 1-1/8 - 7 | 1.0322 | 0.693 | 0.763 | 1-1/8 - 12 | 1.0709 | 0.812 | 0.856 | 1-1/8 - 8 | 1.0438 | 0.728 | 0.790 |
| 1-1/4 - 7 | 1.1572 | 0.890 | 0.969 | 1-1/4 - 12 | 1.1959 | 1.024 | 1.073 | 1-1/4 - 8 | 1.1688 | 0.929 | 1.000 |
| 1-3/8 - 6 | 1.2667 | 1.054 | 1.155 | 1-3/8 - 12 | 1.3209 | 1.260 | 1.315 | 1-3/8 - 8 | 1.2938 | 1.155 | 1.233 |
| 1-1/2 - 6 | 1.3917 | 1.294 | 1.405 | 1-1/2 - 12 | 1.4459 | 1.521 | 1.581 | 1-1/2 - 8 | 1.4188 | 1.405 | 1.492 |
| -- -- | -- | -- | -- | -- -- | -- | -- | -- | 1-5/8 - 8 | 1.5438 | 1.68 | 1.78 |
| 1-3/4 - 5 | 1.6201 | 1.74 | 1.90 | -- -- | -- | -- | -- | 1-3/4 - 8 | 1.6688 | 1.98 | 2.08 |
| -- -- | -- | -- | -- | -- -- | -- | -- | -- | 1-7/8 - 8 | 1.7938 | 2.30 | 2.41 |
| 2 - 4-1/2 | 1.8557 | 2.30 | 2.50 | -- -- | -- | -- | -- | 2 - 8 | 1.9188 | 2.65 | 2.77 |
| 2-¼ - 4-½ | 2.1057 | 3.02 | 3.25 | -- -- | -- | -- | -- | 2-1/4 - 8 | 2.1688 | 3.42 | 3.56 |
| 2-1/2 - 4 | 2.3376 | 3.72 | 4.00 | -- -- | -- | -- | -- | 2-1/2 - 8 | 2.4188 | 4.29 | 4.44 |
| 2-3/4 - 4 | 2.5876 | 4.62 | 4.93 | -- -- | -- | -- | -- | 2-3/4 - 8 | 2.6688 | 5.26 | 5.43 |
| 3 - 4 | 2.8376 | 5.62 | 5.97 | -- -- | -- | -- | -- | 3 - 8 | 2.9188 | 6.32 | 6.51 |
| 3-1/4 - 4 | 3.0876 | 6.72 | 7.10 | -- -- | -- | -- | -- | 3-1/4 - 8 | 3.1688 | 7.49 | 7.69 |
| 3-1/2 - 4 | 3.3376 | 7.92 | 8.33 | -- -- | -- | -- | -- | 3-1/2 - 8 | 3.4188 | 8.75 | 8.96 |
| 3-3/4 - 4 | 3.5876 | 9.21 | 9.66 | -- -- | -- | -- | -- | 3-3/4 - 8 | 3.6688 | 10.11 | 10.34 |
| 4 - 4 | 3.8376 | 10.61 | 11.08 | -- -- | -- | -- | -- | 4 - 8 | 3.9188 | 11.57 | 11.81 |