While the tables above cover the exact dimensions for the "mk" classification, the official documentation provides deeper insights into exceptions, methodology, and legal compliance. To obtain an authorized copy, you can purchase the documents directly from the or your local national standards institute (such as ANSI, DIN, or BSI). Many manufacturing shops also provide summarized, downloadable PDF reference sheets containing these exact matrix tables for quick workshop reference.
These values apply to the rounding or beveling of sharp edges. Nominal Size Range (mm) Tolerance Class m (Medium) Over 3 to 6 3. Angular Dimensions
ISO 2768 is an international standard created to simplify drawing specifications. it establishes for linear and angular dimensions without individual tolerance indications. The standard is divided into two parts: Tolerance Iso 2768 Mk Pdf
Class 'm' avoids over-tolerancing. Specifying unnecessarily tight tolerances drives up manufacturing costs by requiring specialized tools and slower machining speeds. ISO 2768-mk offers a functional compromise. How to Implement it on a Drawing
When a drawing specifies ISO 2768-mK, it also invokes the class for geometrical tolerances. These control the form and position of features without individual callouts. While the tables above cover the exact dimensions
Part 1 of the standard dictates permissible deviations for dimensions without specific tolerance callouts. The allowable variance depends entirely on the nominal size of the feature—larger dimensions are allowed larger variations.
If you are working on a specific manufacturing project, please let me know: These values apply to the rounding or beveling
| Nominal Length Range of Shorter Side (mm) | Permissible Deviation | | :--- | :--- | | up to 10 | ± 1° | | over 10 up to 50 | ± 0°30' | | over 50 up to 120 | ± 0°20' | | over 120 up to 400 | ± 0°10' | | over 400 | ± 0°5' |
ISO 2768-1 also covers tolerances for angles. These are expressed in degrees and minutes (or degrees and arc minutes) and are referenced to the nominal length of the shorter side of the angle.
While "MK" is very common, other combinations are used depending on the application: