METRICcoarse60° flankISO 261

M27 × 3 Thread Dimensions

M27 x 3 is a coarse ISO Metric thread. Pitch is 3 mm, equivalent to 8.47 threads per inch. The recommended tap drill is nominal diameter minus pitch.

Major Ø27 mm
Pitch3 mm
Threads per inch8.47
Pitch Ø25.05 mm
Tap drill24 mm

Thread profile

millimetres unless stated
Thread profile — M27 x 3d 27d2 25.05d3 23.32mm60°P 3h3 1.84tap ⌀24
M27 × 3 — basic profile60° flank angle · Not to scale

Basic information

Designation
M27 x 3
Thread system
ISO Metric
Series
coarse
Standard
ISO 261
Basic profile
ISO 68-1 basic profile
Flank angle
60°

Dimensions

Major diameter
27 mm
Pitch
3 mm
Threads per inch
8.47
Pitch diameter
25.05 mm
Minor diameter (external)
23.32 mm
Minor diameter (internal)
23.75 mm
Thread depth
1.84 mm
Recommended tap drill
Ø 24 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 has a fundamental triangle height H = 0.866025 × P, with pitch diameter d₂ = d − 0.649519 × P, external minor diameter d₃ = d − 1.226869 × P and internal minor diameter D₁ = d − 1.082532 × P; the two minor diameters differ because the external root is rounded while the internal crest is truncated. 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 M27 × 3 yet.

Related

Other pitches at the same 27 mm diameter — a fine pitch on a coarse diameter, or the reverse, is the usual substitution question.

Neighbouring sizes in ISO Metric.