General ISO Geometrical Tolerances Per. ISO 2768

Mechanical Tolerance Standards Menu

The following are general geometrical tolerances per. ISO 2768 for the following:

  • Linear Dimensions
  • External Radius and Chamfer Heights
  • Straightness and Flatness
  • Perpendicularity
  • Symmetry
  • Runout

Related Mechanical Tolerance Design Data

Variations on dimensions without tolerance values are according to " ISO 2768". All tolerance limits are given in mm.

ISO 2768 and derivative geometrical tolerance standards are intened to simplify drawing specifications for mechanical tolerances. ISO 2768 is mainly for parts that are manufactured by way of machniing or removeal of materials.

Linear Dimensions:

Permissible deviations in mm for ranges in nominal lengths f (fine) Tolerance class designation (description) v (very coarse)
m (medium) c (coarse)
0.5 up to 3 ±0.05 ±0.1 ±0.2 -
over 3 up to 6 ±0.05 ±0.1 ±0.3 ±0.5
over 6 up to 30 ±0.1 ±0.2 ±0.5 ±1.0
over 30 up to 120 ±0.15 ±0.3 ±0.8 ±1.5
over 120 up to 400 ±0.2 ±0.5 ±1.2 ±2.5
over 400 up to 1000 ±0.3 ±0.8 ±2.0 ±4.0
over 1000 up to 2000 ±0.5 ±1.2 ±3.0 ±6.0
over 2000 up to 4000 - ±2.0 ±4.0 ±8.0

External Radius and Chamfer Heights

Permissible deviations in mm for ranges in nominal lengths f (fine) Tolerance class designation (description) v (very coarse)
m (middle) c (coarse)
0.5 up to 3 ±0.2 ±0.2 ±0.4 ±0.4
over 3 up to 6 ±0.5 ±0.5 ±1.0 ±1.0
over 6 ±1.0 ±1.0 ±2.0 ±2.0

Angular Dimensions

Permissible deviations in degrees and minutes for ranges in nominal lengths f (fine) Tolerance class designation (description) v (very coarse)
m (middle) c (coarse)
up to 10 ±1º ±1º ±1º30' ±3º
over 10 up to 50 ±0º30' ±0º30' ±1º ±2º
over 50 up to 120 ±0º20' ±0º20' ±0º30' ±1º
over 120 up to 400 ±0º10' ±0º10' ±0º15' ±0º30'
over 400 ±0º5' ±0º5' ±0º10' ±0º20'

Straightness and Flatness

Ranges in nominal lengths in mm Tolerance class
H K L
up to 10 0.02 0.05 0.1
over 10 up to 30 0.05 0.1 0.2
over 30 up to 100 0.1 0.2 0.4
over 100 up to 300 0.2 0.4 0.8
over 300 up to 1000 0.3 0.6 1.2
over 1000 up to 3000 0.4 0.8 1.6

Perpendicularity

Ranges in nominal lengths in mm Tolerance class
H K L
up to 100 0.2 0.4 0.6
over 100 up to 300 0.3 0.6 1
over 300 up to 1000 0.4 0.8 1.5
over 1000 up to 3000 0.5 0.8 2

Symmetry (Position for ISO G&T Standard not-ASME or ANSI GD&T)

Ranges in nominal lengths in mm Tolerance class
H K L
up to 100 0.5 0.6 0.6
over 100 up to 300 0.5 0.6 1
over 300 up to 1000 0.5 0.8 1.5
over 1000 up to 3000 0.5 1 2

Run-Out

Tolerance class
H K L
0.1 0.2 0.5

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