METRICcoarse60° flank

M42 × 4.5 Thread Dimensions

M42 x 4.5 is a coarse pitch METRIC thread. Pitch is 4.5 mm, equivalent to 5.64 threads per inch. The recommended tap drill leaves roughly 75% thread engagement.

Nominal Ø42 mm
Pitch4.5 mm
Threads per inch5.64
Pitch Ø39.08 mm
Tap drill37.5 mm

Thread profile

millimetres unless stated
Thread profile — M42 x 4.5d 42d2 39.08d3 36.48mm60°P 4.5h3 2.76tap ⌀37.5
M42 × 4.5 — basic profile60° flank angle · Not to scale
Designation
M42 x 4.5
Thread system
METRIC
Series
coarse
Flank angle
60°
Major diameter
42 mm / 1.65"
Pitch
4.5 mm
Threads per inch
5.64
Pitch diameter
39.08 mm
Minor diameter (external)
36.48 mm
Minor diameter (internal)
37.13 mm
Thread depth
2.76 mm
Recommended tap drill
Ø 37.5 mm / 1.48"

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.