| Threads Per Inch Chart | ||
|---|---|---|
|
Bolt Size
|
Threads Per Inch (TPI) |
|
| Coarse Thread (UNC) | Fine Thread (UNF) | |
| #0000 | - | 160 |
| #000 | - | 120 |
| #00 | - | 90 |
| #0 | - | 80 |
| #1 | 64 | 72 |
| #2 | 56 | 65 |
| #3 | 48 | 56 |
| #4 | 40 | 48 |
| #5 | 40 | 44 |
| #6 | 32 | 40 |
| #8 | 32 | 36 |
| #10 | 24 | 32 |
| #12 | 24 | 28 |
| 1/4" | 20 | 28 |
| 5/16" | 18 | 24 |
| 3/8" | 16 | 24 |
| 7/16" | 14 | 20 |
| 1/2" | 13 | 20 |
| 9/16" | 12 | 18 |
| 5/8" | 11 | 18 |
| 3/4" | 10 | 16 |
| 7/8" | 9 | 14 |
| 1" | 8 | 12* |
| 1-1/8" | 7 | 12 |
| 1-1/4" | 7 | 12 |
| 1-1/2" | 6 | 12 |
* 12 TPI is the UNF standard however 14 TPI is more common in actual use.
