UNC Unified Coarse Thread · ANSI/ASME B1.1

#3 - 48 UNC Thread: Pitch, Tap Drill & Dimensions

#3 - 48 UNC is a UNC Unified Coarse Thread (ANSI/ASME B1.1) size, with a major diameter of 2.515 mm, 48 threads per inch (0.529 mm pitch). The tap drill is 2.05 mm.

Profile shape (schematic, not to scale)
#3 - 48 UNC thread dimensions
Major Diameter (inch)0.099
Major Diameter (mm)2.515
Tapping Drill Size (mm)2.05
TPI48
Pitch (mm)0.529
Flank angle60°

Common questions

What size drill do I use to tap #3 - 48 UNC?

Use a 2.05 drill. This is the standard tap drill for #3 - 48 UNC; for hard materials or deep threads a slightly larger drill reduces tapping torque.

What is the pitch of #3 - 48 UNC?

The pitch of #3 - 48 UNC is 0.529, 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.

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