Metric Thread Pitch Reference Guide

Diameter
(mm)		 Coarse
(Standard)		 Fine Extra Fine Superfine
M1 0.25 0.2
M1.6 0.35 0.2
M2 0.4 0.25
M2.5 0.45 0.35
M3 0.5 0.35
M3.5 0.6 0.35
M4
ISO 4032
ISO 4035		 0.7 0.5
M5
ISO 4032
ISO 4035		 0.8 0.5
M6
ISO 4032
ISO 4035		 1 0.75
M7 1 0.75
M8
ISO 4032
ISO 4035		 1.25 1
ISO 8673
ISO 8675		 0.75
M10
ISO 4032
ISO 4035		 1.5 1.25 1
ISO 8673
ISO 8675		 0.75
DIN 981(KM0)
M12
ISO 4032
ISO 4035		 1.75 1.5
ISO 8673
ISO 8675
DIN 70852		 1.25 1
DIN 981(KM1)
M14 2 1.5 1.25 1
M15 1
DIN 981(KM2)
Diameter
(mm)		 Coarse
(Standard)		 Fine Extra Fine Superfine
M16
ISO 4032
ISO 4035		 2 1.5
ISO 8673
ISO 8675
DIN 70852		 1
M17 1
DIN 981(KM3)
M18 2.5 2 1.5 1
M20
ISO 4032
ISO 4035		 2.5 2 1.5
ISO 8673
ISO 8675
DIN 70852		 1
DIN 981(KM4)
M22 2.5 2 1.5 1
M24
ISO 4032
ISO 4035		 3 2
ISO 8673
ISO 8675		 1.5
DIN 70852		 1
M25 1.5
DIN 981(KM5)
M27 3 2 1.5 1
M30
ISO 4032
ISO 4035		 3.5 3 2
ISO 8673
ISO 8675		 1.5
DIN 981(KM6)
DIN 70852
M35 1.5
DIN 70852
M36
ISO 4032
ISO 4035		 4 3.5 3
ISO 8673
ISO 8675		 2

This guide details metric thread pitch sizes for different bolt diameters, based on DIN 13-1 and DIN 13-2 standards. It covers four main thread types:

  • Coarse (Standard): Most commonly used for general applications
  • Fine: Offers greater adjustment precision and higher strength
  • Extra Fine: Provides even finer adjustment and increased thread engagement
  • Superfine: Specialized applications requiring the highest precision

When selecting nuts for various thread types, consider the following standards:

  • Standard Threads: Hex Nut Style 1 ISO 4032 (DIN 934)
  • Fine Threads:
    • Hex Nut Style 1 Fine ISO 8673 (DIN 971-1)
    • Hex High Nuts Style 2 Fine ISO 8674 (DIN 971-2)
    • Hex Thin Nut Fine Grade AB ISO 8675 (DIN 439-2)
  • Specialized Applications:
    • KM Locknuts DIN 981
    • Slotted Locknuts DIN 70852

For fine thread applications, consider using Hexagon Head Screws conforming to ISO 8676.