Unified National Fine Thread Chart
24 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) |
|---|---|---|---|---|---|---|
| #0-80 UNF | 80 | 0.06 | 0.0519 | 0.0447 | #56 | 0.0018 |
| #1-72 UNF | 72 | 0.073 | 0.064 | 0.056 | #53 | 0.0027 |
| #2-64 UNF | 64 | 0.086 | 0.0759 | 0.0668 | #50 | 0.0039 |
| #3-56 UNF | 56 | 0.099 | 0.0874 | 0.0771 | #47 | 0.0052 |
| #4-48 UNF | 48 | 0.112 | 0.0985 | 0.0864 | #43 | 0.0065 |
| #5-44 UNF | 44 | 0.125 | 0.1102 | 0.0971 | #39 | 0.0082 |
| #6-40 UNF | 40 | 0.138 | 0.1218 | 0.1073 | #34 | 0.01 |
| #8-36 UNF | 36 | 0.164 | 0.146 | 0.1299 | #29 | 0.0145 |
| #10-32 UNF | 32 | 0.19 | 0.1697 | 0.1517 | 5/32" | 0.0197 |
| #12-28 UNF | 28 | 0.216 | 0.1928 | 0.1722 | #16 | 0.0254 |
| 1/4-28 UNF | 28 | 0.25 | 0.2268 | 0.2062 | #3 | 0.0359 |
| 5/16-24 UNF | 24 | 0.3125 | 0.2854 | 0.2614 | H | 0.0574 |
| 3/8-24 UNF | 24 | 0.375 | 0.3479 | 0.3239 | 21/64" | 0.087 |
| 7/16-20 UNF | 20 | 0.4375 | 0.405 | 0.3762 | W | 0.1176 |
| 1/2-20 UNF | 20 | 0.5 | 0.4675 | 0.4387 | 29/64" | 0.1587 |
| 9/16-18 UNF | 18 | 0.5625 | 0.5264 | 0.4943 | 1/2" | 0.2014 |
| 5/8-18 UNF | 18 | 0.625 | 0.5889 | 0.5568 | 9/16" | 0.2542 |
| 3/4-16 UNF | 16 | 0.75 | 0.7094 | 0.6733 | 11/16" | 0.3705 |
| 7/8-14 UNF | 14 | 0.875 | 0.8286 | 0.7874 | 51/64" | 0.5062 |
| 1-12 UNF | 12 | 1 | 0.9459 | 0.8978 | 29/32" | 0.6587 |
| 1-1/8-12 UNF | 12 | 1.125 | 1.0709 | 1.0228 | 1/1" | 0.8508 |
| 1-1/4-12 UNF | 12 | 1.25 | 1.1959 | 1.1478 | 1/1" | 1.0674 |
| 1-3/8-12 UNF | 12 | 1.375 | 1.3209 | 1.2728 | 1/1" | 1.3086 |
| 1-1/2-12 UNF | 12 | 1.5 | 1.4459 | 1.3978 | 1/1" | 1.5743 |