General Tolerance Iso 2768-mk Jun 2026

For basic dimensions like lengths, widths, heights, and diameters, class "m" dictates the following symmetric tolerances: Nominal Dimension Range (mm) Permissible Deviation (mm) over 3 to 6 over 6 to 30 over 30 to 120 over 120 to 400 over 400 to 1000 over 1000 to 2000 over 2000 to 4000

For a side up to 100mm, the limit is 0.4mm.

For parallelism , the tolerance equals the value of the size tolerance. For positional tolerances , the standard recommends using ISO 2768-2 only for "non-functional" features; otherwise, individually specify. general tolerance iso 2768-mk

Permissible Deviations for Broken Edges (External Radii and Chamfers)

| Tolerance Class (ISO 2768) | Part 1 (Linear) | Part 2 (Geometry) | Typical Use | | :--- | :--- | :--- | :--- | | | Tightest | Medium | Precision instruments | | m (Medium) | Standard | – | General machining (default) | | c (Coarse) | Loose | – | Fabrications, non-critical | | v (Very coarse) | Very loose | – | Castings before machining | For basic dimensions like lengths, widths, heights, and

| Nominal Length Range (mm) | Tolerance Class H | Tolerance Class K | Tolerance Class L | | :--- | :---: | :---: | :---: | | | 0.02 | 0.05 | 0.10 | | 10 up to 30 | 0.05 | 0.10 | 0.20 | | 30 up to 100 | 0.10 | 0.20 | 0.40 | | 100 up to 300 | 0.20 | 0.40 | 0.80 | | 300 up to 1000 | 0.30 | 0.60 | 1.20 | | 1000 up to 3000 | 0.40 | 0.80 | 1.60 |

Defines the tolerance class for geometrical features like straightness, flatness, and symmetry. Permissible Deviations for Broken Edges (External Radii and

ISO 2768-1 defines four precision levels. The lower-case letter in "mK" stands for Medium .

Geometrical tolerances control the form, orientation, and location of features. ISO 2768-2 defines three classes for geometrical tolerances: H, K, and L.

Tolerances are scaled according to the size of the nominal dimension. Larger dimensions receive wider tolerance zones because variations naturally increase with part size. 1. Linear Dimensions