UNC Unified Coarse Thread · ANSI/ASME B1.1
#12 - 24 UNC Thread: Pitch, Tap Drill & Dimensions
#12 - 24 UNC is a UNC Unified Coarse Thread (ANSI/ASME B1.1) size, with a major diameter of 5.486 mm, 24 threads per inch (1.058 mm pitch). The tap drill is 4.47 mm.
| Major Diameter (inch) | 0.216 |
|---|---|
| Major Diameter (mm) | 5.486 |
| Tapping Drill Size (mm) | 4.47 |
| TPI | 24 |
| Pitch (mm) | 1.058 |
| Flank angle | 60° |
Common questions
What size drill do I use to tap #12 - 24 UNC?
Use a 4.47 drill. This is the standard tap drill for #12 - 24 UNC; for hard materials or deep threads a slightly larger drill reduces tapping torque.
What is the pitch of #12 - 24 UNC?
The pitch of #12 - 24 UNC is 1.058, meaning the thread advances that distance in one full turn.
Where can I find other UNC Unified Coarse Thread sizes?
The full UNC Unified Coarse 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.