UNCcoarse60° flank

#6-32 UNC Thread Dimensions

#6-32 UNC is a coarse pitch UNC thread. There are 32 threads per inch, giving a pitch of 0.79 mm. The recommended tap drill leaves roughly 75% thread engagement.

Nominal Ø3.51 mm
Pitch0.79 mm
Threads per inch32
Pitch Ø-9.59 mm
Tap drill-16.65 mm

Thread profile

millimetres unless stated
Thread profile — #6-32 UNCd 3.51d2 -9.59d3 -21.23mm60°P 0.79h3 12.37tap ⌀-16.65
#6-32 UNC — basic profile60° flank angle · Not to scale
Designation
#6-32 UNC
Thread system
UNC
Series
coarse
Flank angle
60°
Major diameter
3.51 mm / 0.14"
Pitch
0.79 mm
Threads per inch
32
Pitch diameter
-9.59 mm
Minor diameter (external)
-21.23 mm
Minor diameter (internal)
-18.32 mm
Thread depth
12.37 mm
Recommended tap drill
Ø -16.65 mm / -0.6557"

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.