UNF - Unified National Fine Thread
UNF threads ANSI B1.1Nominal Diameter (in) | Threads per inch | Major Diameter (in) | Major Diameter (mm) | Tapping Drill Size (mm) | Pitch (mm) |
---|---|---|---|---|---|
0 | 80 | 0.06 | 1.524 | 1.25 | 0.317 |
1 | 72 | 0.073 | 1.854 | 1.55 | 0.353 |
2 | 64 | 0.068 | 2.184 | 1.9 | 0.397 |
3 | 56 | 0.099 | 2.515 | 2.15 | 0.453 |
4 | 48 | 0.112 | 2.845 | 2.4 | 0.529 |
5 | 44 | 0.125 | 3.175 | 2.7 | 0.577 |
6 | 40 | 0.138 | 3.505 | 2.95 | 0.635 |
8 | 36 | 0.164 | 4.166 | 3.5 | 0.705 |
10 | 32 | 0.19 | 4.826 | 4.1 | 0.794 |
12 | 28 | 0.216 | 5.486 | 4.7 | 0.907 |
1/4" | 28 | 0.25 | 6.35 | 5.5 | 0.907 |
5/16" | 24 | 0.313 | 7.938 | 6.9 | 1.058 |
3/8" | 24 | 0.375 | 9.525 | 8.5 | 1.058 |
7/16" | 20 | 0.438 | 11.112 | 9.9 | 1.27 |
1/2" | 20 | 0.5 | 12.7 | 11.5 | 1.27 |
9/16" | 18 | 0.563 | 14.288 | 12.9 | 1.411 |
5/8" | 18 | 0.625 | 15.875 | 14.5 | 1.411 |
3/4" | 16 | 0.75 | 19.05 | 17.5 | 1.587 |
7/8" | 14 | 0.875 | 22.225 | 20.4 | 1.814 |
1" | 12 | 1 | 25.4 | 23.25 | 2.117 |
1 1/8" | 12 | 1.125 | 28.575 | 26.5 | 2.117 |
1 1/4" | 12 | 1.25 | 31.75 | 29.5 | 2.117 |
1 3/8" | 12 | 1.375 | 43.925 | 32.75 | 2.117 |
1 1/2" | 12 | 1.5 | 38.1 | 36 | 2.117 |