UNFfine60° flank

#0-80 UNF Thread Dimensions

#0-80 UNF is a fine pitch UNF thread. There are 80 threads per inch, giving a pitch of 0.32 mm. The recommended tap drill leaves roughly 75% thread engagement.

Nominal Ø1.52 mm
Pitch0.32 mm
Threads per inch80
Pitch Ø-3.71 mm
Tap drill-6.54 mm

Thread profile

millimetres unless stated
Thread profile — #0-80 UNFd 1.52d2 -3.71d3 -8.37mm60°P 0.32h3 4.95tap ⌀-6.54
#0-80 UNF — basic profile60° flank angle · Not to scale
Designation
#0-80 UNF
Thread system
UNF
Series
fine
Flank angle
60°
Major diameter
1.52 mm / 0.06"
Pitch
0.32 mm
Threads per inch
80
Pitch diameter
-3.71 mm
Minor diameter (external)
-8.37 mm
Minor diameter (internal)
-7.21 mm
Thread depth
4.95 mm
Recommended tap drill
Ø -6.54 mm / -0.2575"

How these values are derived

Basic ISO thread geometry uses the fundamental triangle height H = 0.866025 × P. External minor diameter d₃ = d − 1.226869 × P, internal minor diameter D₁ = d − 1.082532 × P. Tap drill is given as nominal diameter minus pitch, which approximates a 75% thread engagement — adjust for tough materials or deep holes.