Home › Imperial Fine (UNF)
🔧 Imperial Fine (UNF)
Fine-thread UNF imperial bolts used in automotive and aerospace. Spanner size, threads per inch, tap drill and Grade 5 torque.
| Size | Wrench | Pitch | Torque |
|---|---|---|---|
| 1/4-28 UNF bolt | 7/16 in | 28 TPI (fine) | 17 Nm (12.5 ft·lb) |
| 5/16-24 UNF bolt | 1/2 in | 24 TPI (fine) | 34 Nm (25 ft·lb) |
| 3/8-24 UNF bolt | 9/16 in | 24 TPI (fine) | 53 Nm (39 ft·lb) |
| 7/16-20 UNF bolt | 5/8 in | 20 TPI (fine) | 85 Nm (63 ft·lb) |
| 1/2-20 UNF bolt | 3/4 in | 20 TPI (fine) | 115 Nm (85 ft·lb) |
| 9/16-18 UNF bolt | 13/16 in | 18 TPI (fine) | 165 Nm (122 ft·lb) |
| 5/8-18 UNF bolt | 15/16 in | 18 TPI (fine) | 225 Nm (166 ft·lb) |
| 3/4-16 UNF bolt | 1-1/8 in | 16 TPI (fine) | 390 Nm (288 ft·lb) |
All imperial fine (unf)
1/4-287/16 in · 28 TPI (fine)5/16-241/2 in · 24 TPI (fine)3/8-249/16 in · 24 TPI (fine)7/16-205/8 in · 20 TPI (fine)1/2-203/4 in · 20 TPI (fine)9/16-1813/16 in · 18 TPI (fine)5/8-1815/16 in · 18 TPI (fine)3/4-161-1/8 in · 16 TPI (fine)