Screw Thread Nomenclature

ISO 261 metric thread dimensions — Learn • Explore • Practice • Quiz

Mode

Standard ISO 261

Thread Size

M6 × 1.00

Coarse Pitch

Standard Pitches

Pitch 1.000 mm

0.75 1.00

Major diameter (d) and thread angle (60°) are always constant. Drag the pitch slider to see how d₂, d₁, h, and helix angle change with pitch.

Diameters

Major dia (d)6.000 mm

Pitch dia (d₂)5.350 mm

Minor dia (d₁)4.918 mm

Thread Profile

Pitch (P)1.000 mm

Thread depth (h)0.541 mm

Thread angle60°

Helix angle (λ)3.40°

Step-by-step Calculation

ISO 261 Screw Thread Nomenclature — Interactive Trainer

What You’ll Learn

This trainer covers the complete ISO 261 metric screw thread system. Learn to identify and calculate all key dimensions: major diameter, minor diameter, pitch diameter, pitch, thread depth, thread angle, and helix angle.

Standard Metric Coarse Threads (M2 – M12)

M2 — d = 2 mm, P = 0.4 mm
M3 — d = 3 mm, P = 0.5 mm
M5 — d = 5 mm, P = 0.8 mm
M6 — d = 6 mm, P = 1.0 mm
M8 — d = 8 mm, P = 1.25 mm
M10 — d = 10 mm, P = 1.5 mm
M12 — d = 12 mm, P = 1.75 mm

Key Formulas

Pitch diameter: d₂ = d − 0.6495 × P. Minor diameter: d₁ = d − 1.0825 × P. Thread depth: h = 0.5413 × P. All metric threads have a 60° thread angle.

Who Is This For?

Engineering students, apprentice machinists, and anyone studying mechanical engineering metrology. Covers the ISO 261 standard used worldwide for metric screw threads.