UNF Unified Fine Thread · ANSI/ASME B1.1

3/4" - 16 UNF Thread: Pitch, Tap Drill & Dimensions

3/4" - 16 UNF is a UNF Unified Fine Thread (ANSI/ASME B1.1) size, with a major diameter of 19.050 mm, 16 threads per inch (1.587 mm pitch). The tap drill is 17.50 mm.

Profile shape (schematic, not to scale)
3/4" - 16 UNF thread dimensions
Major Diameter (inch)0.750
Major Diameter (mm)19.050
Tapping Drill Size (mm)17.50
TPI16
Pitch (mm)1.587
Flank angle60°

Common questions

What size drill do I use to tap 3/4" - 16 UNF?

Use a 17.50 drill. This is the standard tap drill for 3/4" - 16 UNF; for hard materials or deep threads a slightly larger drill reduces tapping torque.

What is the pitch of 3/4" - 16 UNF?

The pitch of 3/4" - 16 UNF is 1.587, 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.

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