METRICcoarse60° flankISO 261

M64 × 6 Thread Dimensions

M64 x 6 is a coarse ISO Metric thread. Pitch is 6 mm, equivalent to 4.23 threads per inch. The recommended tap drill leaves roughly 75% thread engagement.

Major Ø64 mm
Pitch6 mm
Threads per inch4.23
Pitch Ø60.1 mm
Tap drill58 mm

Thread profile

millimetres unless stated
Thread profile — M64 x 6d 64d2 60.1d3 56.64mm60°P 6h3 3.681tap ⌀58
M64 × 6 — basic profile60° flank angle · Not to scale

Basic information

Designation
M64 x 6
Thread system
ISO Metric
Series
coarse
Standard
ISO 261
Basic profile
ISO 68-1 basic profile
Flank angle
60°

Dimensions

Major diameter
64 mm
Pitch
6 mm
Threads per inch
4.23
Pitch diameter
60.1 mm
Minor diameter (external)
56.64 mm
Minor diameter (internal)
57.5 mm
Thread depth
3.681 mm
Recommended tap drill
Ø 58 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

No specification in this database uses M64 × 6 yet.

Related

Other pitches at the same 64 mm diameter — a fine pitch on a coarse diameter, or the reverse, is the usual substitution question.

Neighbouring sizes in ISO Metric.