METRICfine60° flankISO 262

M27 × 2 fine Thread Dimensions

M27 x 2 (fine) is a fine ISO Metric thread. Pitch is 2 mm, equivalent to 12.7 threads per inch. The recommended tap drill is nominal diameter minus pitch.

Major Ø27 mm
Pitch2 mm
Threads per inch12.7
Pitch Ø25.7 mm
Tap drill25 mm

Thread profile

millimetres unless stated
Thread profile — M27 x 2 (fine)d 27d2 25.7d3 24.55mm60°P 2h3 1.227tap ⌀25
M27 × 2 fine — basic profile60° flank angle · Not to scale

Basic information

Designation
M27 x 2 (fine)
Thread system
ISO Metric
Series
fine
Standard
ISO 262
Basic profile
ISO 68-1 basic profile
Flank angle
60°

Dimensions

Major diameter
27 mm
Pitch
2 mm
Threads per inch
12.7
Pitch diameter
25.7 mm
Minor diameter (external)
24.55 mm
Minor diameter (internal)
24.83 mm
Thread depth
1.227 mm
Recommended tap drill
Ø 25 mm

How these values are derived

computed from the basic profile

These figures follow the ISO 68-1 basic profile of ISO 262. 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 × 2 fine 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.