UNEFextra fine60° flankASME B1.1

9/16-24 UNEF Thread Dimensions

9/16-24 UNEF is a Unified National Extra Fine thread. There are 24 threads per inch on a 0.5625 in major diameter, giving a metric-equivalent pitch of 1.058 mm. The recommended tap drill is nominal diameter minus pitch.

Major Ø0.5625 in
Threads per inch24
Pitch (metric)1.058 mm
Pitch Ø0.5354 in
Tap drill0.5208 in

Thread profile

millimetres unless stated
Thread profile — 9/16-24 UNEFd 14.287d2 13.6d3 12.99mm60°P 1.058h3 0.649tap ⌀13.229
9/16-24 UNEF — basic profile60° flank angle · Not to scale

Basic information

Designation
9/16-24 UNEF
Series
extra fine
Standard
ASME B1.1
Basic profile
Unified basic profile
Flank angle
60°

Dimensions

Major diameter
0.5625 in / 14.287 mm
Pitch (metric equivalent)
1.058 mm
Threads per inch
24
Pitch diameter
0.5354 in / 13.6 mm
Minor diameter (external)
0.5114 in / 12.99 mm
Minor diameter (internal)
0.5173 in / 13.14 mm
Thread depth
0.0256 in / 0.649 mm
Recommended tap drill
Ø 0.5208 in / 13.229 mm

How these values are derived

computed from the basic profile

These figures follow the Unified basic profile of ASME B1.1. A 60° basic profile has a fundamental triangle height H = 0.866025 × P, with pitch diameter d₂ = d − 0.649519 × P, external minor diameter d₃ = d − 1.226869 × P and internal minor diameter D₁ = d − 1.082532 × P; the two minor diameters differ because the external root is rounded while the internal crest is truncated. The recommended tap drill is given as nominal diameter minus pitch, which approximates 75% thread engagement — adjust it for tough materials or deep holes.

Compatible parts0 specification pages

No specification in this database uses 9/16-24 UNEF yet.

Related

Neighbouring sizes in Unified National Extra Fine.