Standard Thread Pitch Chart
Technical Menu Posted on July 2nd, 2015 by vapro| 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 @ Minor Dia. | Tensile Stress Area | Nominal Size and Threads Per In. | Basic Pitch Dia. | Section @ Minor Dia. |
| In. | Sq in. | Sq in. | In. | Sq in. | Sq in. | In. | Sq in. | |||
| 3⁄8 – 16 | 0.3344 | 0.0678 | 0.0775 | 3⁄8 – 24 | 0.3479 | 0.0809 | – – | – | – | |
| 7⁄16 – 14 | 0.3911 | 0.0933 | 0.1063 | 7⁄16 – 20 | 0.405 | 0.109 | – – | – | – | |
| 1⁄2 – 13 | 0.45 | 0.1257 | 0.1419 | 1⁄2 – 20 | 0.4675 | 0.1486 | – – | – | – | |
| 9⁄16 – 12 | 0.5084 | 0.162 | 0.182 | 9⁄16 – 18 | 0.5264 | 0.189 | – – | – | – | |
| 5⁄8 – 11 | 0.566 | 0.202 | 0.226 | 5⁄8 – 18 | 0.5889 | 0.24 | – – | – | – | |
| 3⁄4 – 10 | 0.685 | 0.302 | 0.334 | 3⁄4 – 16 | 0.7094 | 0.351 | – – | – | – | |
| 7⁄8 – 9 | 0.8028 | 0.419 | 0.462 | 7⁄8 – 14 | 0.8286 | 0.48 | – – | – | – | |
| 1-8 | 0.9188 | 0.551 | 0.606 | 1-12 | 0.9459 | 0.625 | 1-8 | 0.9188 | 0.551 | |
| 11⁄8 – 7 | 1.0322 | 0.693 | 0.763 | 11⁄8 – 12 | 1.0709 | 0.812 | 11⁄8 – 8 | 1.0438 | 0.728 | |
| 11⁄4 – 7 | 1.1572 | 0.89 | 0.969 | 11⁄4 – 12 | 1.1959 | 1.024 | 11⁄4 – 8 | 1.1688 | 0.929 | |
| 13⁄8 – 6 | 1.2667 | 1.054 | 1.155 | 13⁄8 – 12 | 1.3209 | 1.26 | 13⁄8 – 8 | 1.2938 | 1.155 | |
| 11⁄2 – 6 | 1.3917 | 1.294 | 1.405 | 11⁄2 – 12 | 1.4459 | 1.521 | 11⁄2 – 8 | 1.4188 | 1.405 | |
| – – | – | – | – – | – | – | – | 15⁄8 – 8 | 1.5438 | 1.68 | |
| 13⁄4 – 5 | 1.6201 | 1.74 | 1.90 | – – | – | – | – | 13⁄4 – 8 | 1.6688 | 1.98 |
| – – | – | – | – – | – | – | – | 17⁄8 – 8 | 1.7938 | 2.3 | |
| 2 – 41⁄2 | 1.8557 | 2.3 | 2.50 | – – | – | – | – | 2-8 | 1.9188 | 2.65 |
| 21⁄4-4-1⁄2 | 2.1057 | 3.02 | 3.25 | – – | – | – | – | 21⁄4 – 8 | 2.1688 | 3.42 |
| 21⁄2 – 4 | 2.3376 | 3.72 | 4.00 | – – | – | – | – | 21⁄2 – 8 | 2.4188 | 4.29 |
| 23⁄4 – 4 | 2.5876 | 4.62 | 4.93 | – – | – | – | – | 23⁄4 – 8 | 2.6688 | 5.26 |
| 3-4 | 2.8376 | 5.62 | 5.97 | – – | – | – | – | 3 – 8 | 2.9188 | 6.32 |
| 31⁄4 – 4 | 3.0876 | 6.72 | 7.10 | – – | – | – | – | 31⁄4 – 8 | 3.1688 | 7.49 |
| 31⁄2 – 4 | 3.3376 | 7.92 | 8.33 | – – | – | – | – | 31⁄2 – 8 | 3.4188 | 8.75 |
| 33⁄4 – 4 | 3.5876 | 9.21 | 9.66 | – – | – | – | – | 33⁄4 – 8 | 3.6688 | 10.11 |
| 4-4 | 3.8376 | 10.61 | 11.08 | – – | – | – | – | 4 – 8 | 3.9188 | 11.57 |
