METRICfine60° flankISO 262

M30 × 2 fine Thread Dimensions

M30 x 2 (fine) is a fine ISO Metric thread. Pitch is 2 mm, equivalent to 12.7 threads per inch. The recommended tap drill leaves roughly 75% thread engagement.

Major Ø30 mm
Pitch2 mm
Threads per inch12.7
Pitch Ø28.7 mm
Tap drill28 mm

Thread profile

millimetres unless stated
Thread profile — M30 x 2 (fine)d 30d2 28.7d3 27.55mm60°P 2h3 1.227tap ⌀28
M30 × 2 fine — basic profile60° flank angle · Not to scale

Basic information

Designation
M30 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
30 mm
Pitch
2 mm
Threads per inch
12.7
Pitch diameter
28.7 mm
Minor diameter (external)
27.55 mm
Minor diameter (internal)
27.83 mm
Thread depth
1.227 mm
Recommended tap drill
Ø 28 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 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 M30 × 2 fine yet.

Related

Other pitches at the same 30 mm diameter — a fine pitch on a coarse diameter, or the reverse, is the usual substitution question.

Neighbouring sizes in ISO Metric.