Unified National Coarse Thread Chart
33 thread sizes with dimensions calculated per ASME B1.1. Click any thread for full specifications.
| Thread | TPI | Major Ø (in) | Pitch Ø (in) | Minor Ø (in) | Tap Drill | Stress Area (in²) |
|---|---|---|---|---|---|---|
| #1-64 UNC | 64 | 0.073 | 0.0629 | 0.0538 | #54 | 0.0026 |
| #2-56 UNC | 56 | 0.086 | 0.0744 | 0.0641 | #51 | 0.0036 |
| #3-48 UNC | 48 | 0.099 | 0.0855 | 0.0734 | #48 | 0.0048 |
| #4-40 UNC | 40 | 0.112 | 0.0958 | 0.0813 | #44 | 0.0059 |
| #5-40 UNC | 40 | 0.125 | 0.1088 | 0.0943 | #40 | 0.0078 |
| #6-32 UNC | 32 | 0.138 | 0.1177 | 0.0997 | #37 | 0.0089 |
| #8-32 UNC | 32 | 0.164 | 0.1437 | 0.1257 | #30 | 0.0138 |
| #10-24 UNC | 24 | 0.19 | 0.1629 | 0.1389 | #27 | 0.0172 |
| #12-24 UNC | 24 | 0.216 | 0.1889 | 0.1649 | 11/64" | 0.0238 |
| 1/4-20 UNC | 20 | 0.25 | 0.2175 | 0.1887 | #9 | 0.0312 |
| 5/16-18 UNC | 18 | 0.3125 | 0.2764 | 0.2443 | E | 0.0516 |
| 3/8-16 UNC | 16 | 0.375 | 0.3344 | 0.2983 | 5/16" | 0.0764 |
| 7/16-14 UNC | 14 | 0.4375 | 0.3911 | 0.3499 | 23/64" | 0.1048 |
| 1/2-13 UNC | 13 | 0.5 | 0.45 | 0.4056 | Z | 0.1401 |
| 9/16-12 UNC | 12 | 0.5625 | 0.5084 | 0.4603 | 15/32" | 0.1797 |
| 5/8-11 UNC | 11 | 0.625 | 0.566 | 0.5135 | 17/32" | 0.2233 |
| 3/4-10 UNC | 10 | 0.75 | 0.6851 | 0.6273 | 41/64" | 0.3308 |
| 7/8-9 UNC | 9 | 0.875 | 0.8028 | 0.7387 | 3/4" | 0.4569 |
| 1-8 UNC | 8 | 1 | 0.9188 | 0.8466 | 55/64" | 0.5995 |
| 1-1/8-7 UNC | 7 | 1.125 | 1.0322 | 0.9497 | 31/32" | 0.7553 |
| 1-1/4-7 UNC | 7 | 1.25 | 1.1572 | 1.0747 | 1/1" | 0.9601 |
| 1-3/8-6 UNC | 6 | 1.375 | 1.2668 | 1.1705 | 1/1" | 1.1435 |
| 1-1/2-6 UNC | 6 | 1.5 | 1.3918 | 1.2955 | 1/1" | 1.3926 |
| 1-3/4-5 UNC | 5 | 1.75 | 1.6201 | 1.5046 | 1/1" | 1.8819 |
| 2-4.5 UNC | 4.5 | 2 | 1.8557 | 1.7274 | 1/1" | 2.4758 |
| 2-1/4-4.5 UNC | 4.5 | 2.25 | 2.1057 | 1.9774 | 1/1" | 3.2221 |
| 2-1/2-4 UNC | 4 | 2.5 | 2.3376 | 2.1933 | 1/1" | 3.9669 |
| 2-3/4-4 UNC | 4 | 2.75 | 2.5876 | 2.4433 | 1/1" | 4.8986 |
| 3-4 UNC | 4 | 3 | 2.8376 | 2.6933 | 1/1" | 5.9284 |
| 3-1/4-4 UNC | 4 | 3.25 | 3.0876 | 2.9433 | 1/1" | 7.0564 |
| 3-1/2-4 UNC | 4 | 3.5 | 3.3376 | 3.1933 | 1/1" | 8.2825 |
| 3-3/4-4 UNC | 4 | 3.75 | 3.5876 | 3.4433 | 1/1" | 9.6069 |
| 4-4 UNC | 4 | 4 | 3.8376 | 3.6933 | 1/1" | 11.0294 |