UNF
Unified Fine Thread, Standardised in 1918, Angle of Thread 60°.
| Size | Tapping Drill mm | Pitch mm | TPI | OD mm |
| 2-64 UNF | 1.90 | 0.40 | 64 | 2.18 |
| 3-56 UNF | 2.15 | 0.45 | 56 | 2.51 |
| 4-48 UNF | 2.40 | 0.53 | 48 | 2.84 |
| 6-40 UNF | 2.95 | 0.64 | 40 | 3.51 |
| 8-36 UNF | 3.55 | 0.71 | 36 | 4.17 |
| 10-32 UNF | 4.10 | 0.79 | 32 | 4.83 |
| 12-28 UNF | 4.65 | 0.91 | 28 | 5.49 |
| 1/4-28 UNF | 5.50 | 0.91 | 28 | 6.35 |
| 5/16-24 UNF | 6.90 | 1.06 | 24 | 7.94 |
| 3/8-24 UNF | 8.50 | 1.06 | 24 | 9.53 |
| 7/16-20 UNF | 9.90 | 1.27 | 20 | 11.11 |
| 1/2-20 UNF | 11.40 | 1.27 | 20 | 12.70 |
| 9/16-18 UNF | 12.90 | 1.41 | 18 | 14.29 |
| 5/8-18 UNF | 14.50 | 1.41 | 18 | 15.88 |
| 3/4-16 UNF | 17.46 | 1.59 | 16 | 19.05 |
| 7/8-14 UNF | 20.42 | 1.81 | 14 | 22.23 |
| 1-12 UNF | 23.25 | 2.12 | 12 | 25.40 |
See also: British Association Threads, British Standard Whitworth, Thread, UNC.
Subjects: Mechanical Engineering