UNF Unified Fine Thread · ANSI/ASME B1.1
1" - 12 UNF Thread: Pitch, Tap Drill & Dimensions
1" - 12 UNF is a UNF Unified Fine Thread (ANSI/ASME B1.1) size, with a major diameter of 25.400 mm, 12 threads per inch (2.117 mm pitch). The tap drill is 23.25 mm.
| Major Diameter (inch) | 1.000 |
|---|---|
| Major Diameter (mm) | 25.400 |
| Tapping Drill Size (mm) | 23.25 |
| TPI | 12 |
| Pitch (mm) | 2.117 |
| Flank angle | 60° |
Common questions
What size drill do I use to tap 1" - 12 UNF?
Use a 23.25 drill. This is the standard tap drill for 1" - 12 UNF; for hard materials or deep threads a slightly larger drill reduces tapping torque.
What is the pitch of 1" - 12 UNF?
The pitch of 1" - 12 UNF is 2.117, meaning the thread advances that distance in one full turn.
Where can I find other UNF Unified Fine Thread sizes?
The full UNF Unified Fine Thread table, with every size and a live filter, is on its standard page, and the Thread Finder searches all 73 standards at once.
Reference values; computed values use the ISO basic profile. Verify against the current standard before production use.