ASME B1.160° flank
Unified National Fine Threads
The inch fine series. More threads per inch than UNC at the same diameter — finer adjustment, better resistance to vibration loosening, and less thread depth to cut, at the cost of a weaker thread form. 23 designations are listed here, all quoted in inches.
Dimensions23 sizes
| Designation | TPI | Major (in) | Pitch Ø (in) | Minor ext (in) | Tap drill (in) |
|---|---|---|---|---|---|
| #0-80 UNF | 80 | 0.06 | 0.052 | 0.0445 | 0.0475 |
| #1-72 UNF | 72 | 0.073 | 0.0642 | 0.0559 | 0.0591 |
| #2-64 UNF | 64 | 0.086 | 0.076 | 0.0669 | 0.0704 |
| #3-56 UNF | 56 | 0.099 | 0.0874 | 0.0772 | 0.0811 |
| #4-48 UNF | 48 | 0.112 | 0.0984 | 0.0866 | 0.0912 |
| #5-44 UNF | 44 | 0.125 | 0.1102 | 0.0972 | 0.1023 |
| #6-40 UNF | 40 | 0.138 | 0.1217 | 0.1075 | 0.113 |
| #8-36 UNF | 36 | 0.164 | 0.1461 | 0.1299 | 0.1362 |
| #10-32 UNF | 32 | 0.19 | 0.1697 | 0.1516 | 0.1587 |
| #12-28 UNF | 28 | 0.216 | 0.1929 | 0.172 | 0.1803 |
| 1/4-28 UNF | 28 | 0.25 | 0.2268 | 0.2063 | 0.2143 |
| 5/16-24 UNF | 24 | 0.3125 | 0.2854 | 0.2614 | 0.2708 |
| 3/8-24 UNF | 24 | 0.375 | 0.348 | 0.324 | 0.3333 |
| 7/16-20 UNF | 20 | 0.4375 | 0.4051 | 0.376 | 0.3875 |
| 1/2-20 UNF | 20 | 0.5 | 0.4677 | 0.4386 | 0.45 |
| 9/16-18 UNF | 18 | 0.5625 | 0.5264 | 0.4945 | 0.5069 |
| 5/8-18 UNF | 18 | 0.625 | 0.589 | 0.5567 | 0.5694 |
| 3/4-16 UNF | 16 | 0.75 | 0.7094 | 0.6732 | 0.6875 |
| 7/8-14 UNF | 14 | 0.875 | 0.8287 | 0.7874 | 0.8036 |
| 1-12 UNF | 12 | 1 | 0.9461 | 0.8976 | 0.9167 |
| 1-1/8-12 UNF | 12 | 1.125 | 1.0709 | 1.0228 | 1.0417 |
| 1-1/4-12 UNF | 12 | 1.25 | 1.1961 | 1.1476 | 1.1667 |
| 1-1/2-12 UNF | 12 | 1.5 | 1.4461 | 1.3976 | 1.4167 |