ASME B1.160° flank
Unified National Extra Fine Threads
The extra fine inch series, used where wall thickness is critical: thin-wall tube and aircraft fittings. Rarely stocked outside specialist suppliers, so check availability before designing one in. 9 designations are listed here, all quoted in inches.
Dimensions9 sizes
| Designation | TPI | Major (in) | Pitch Ø (in) | Minor ext (in) | Tap drill (in) |
|---|---|---|---|---|---|
| 1/4-32 UNEF | 32 | 0.25 | 0.2295 | 0.2118 | 0.2187 |
| 5/16-32 UNEF | 32 | 0.3125 | 0.2921 | 0.274 | 0.2813 |
| 3/8-32 UNEF | 32 | 0.375 | 0.3547 | 0.3366 | 0.3437 |
| 7/16-28 UNEF | 28 | 0.4375 | 0.4142 | 0.3937 | 0.4018 |
| 1/2-28 UNEF | 28 | 0.5 | 0.4768 | 0.4563 | 0.4643 |
| 9/16-24 UNEF | 24 | 0.5625 | 0.5354 | 0.5114 | 0.5208 |
| 5/8-24 UNEF | 24 | 0.625 | 0.598 | 0.574 | 0.5833 |
| 3/4-20 UNEF | 20 | 0.75 | 0.7177 | 0.6886 | 0.7 |
| 7/8-20 UNEF | 20 | 0.875 | 0.8425 | 0.8138 | 0.825 |