METRICcoarse60° flankISO 261

M24 × 3 Thread Dimensions

M24 x 3 is a coarse ISO Metric thread. Pitch is 3 mm, equivalent to 8.47 threads per inch. The recommended tap drill leaves roughly 75% thread engagement.

Major Ø24 mm
Pitch3 mm
Threads per inch8.47
Pitch Ø22.05 mm
Tap drill21 mm

Thread profile

millimetres unless stated
Thread profile — M24 x 3d 24d2 22.05d3 20.32mm60°P 3h3 1.84tap ⌀21
M24 × 3 — basic profile60° flank angle · Not to scale

Basic information

Designation
M24 x 3
Thread system
ISO Metric
Series
coarse
Standard
ISO 261
Basic profile
ISO 68-1 basic profile
Flank angle
60°

Dimensions

Major diameter
24 mm
Pitch
3 mm
Threads per inch
8.47
Pitch diameter
22.05 mm
Minor diameter (external)
20.32 mm
Minor diameter (internal)
20.75 mm
Thread depth
1.84 mm
Recommended tap drill
Ø 21 mm

How these values are derived

computed from the basic profile

These figures follow the ISO 68-1 basic profile of ISO 261. A 60° basic profile uses a fundamental triangle height H = 0.866025 × P, with external minor diameter d₃ = d − 1.226869 × P and internal minor diameter D₁ = d − 1.082532 × P; the two differ because the external root is rounded while the internal crest is truncated. A 55° Whitworth profile uses H = 0.960491 × P and a thread height of 0.640327 × P. 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

All M24 fasteners

No specification in this database uses M24 × 3 yet.

Related

Other pitches at the same 24 mm diameter — a fine pitch on a coarse diameter, or the reverse, is the usual substitution question.

Neighbouring sizes in ISO Metric.