ISO 2768 Part 1 is intended to simplify drawing indications and it specifies general tolerances for linear and angular dimensions without individual tolerance indications in four tolerance classes. It applies to the dimensions of parts that are produced by metal removal or parts that are formed with sheet metal fabrication.
ISO 2768 Part 1 only applies to the following dimensions which do not have an individual tolerance indication:
a) linear dimensions (e.g. external sizes, internal sizes, step sizes, diameters, radii, distances, external radii and chamfer heights for broken edges);
General Tolerances to DIN ISO 2768 Created Date: 4/26/2018 3:18:31 PM. 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 intendedto simplify drawing specifications for mechanical tolerances. ISO 2768 is mainly for parts that are manufactured by way of machining or removal of materials. If general tolerances according to ISO 2768-1 are valid, the following has to be inserted in the title box, i.e. For tolerance class medium. ISO 2768 – m or general tolerance ISO 2768 – m. For new designs only the general tolerance according to DIN ISO 2768-1 should be valid.
b) angular dimensions, including angular dimensions usually not indicated, e.g. right angles (90°). unless reference to ISO 2768-2 is made, or angles of uniform polygons;
c) linear and angular dimensions produced by machining assembled parts.
It does not apply for the following dimensions:
a) linear and angular dimensions which are covered by reference to other standards on general tolerances;
b) auxiliary dimensions indicated in brackets;
c) theoretically exact dimensions indicated in rectangular frames.
Din Iso 2768 Mk Chart
Note:
1. These tolerances may be suitable for use with materials other than metal.
2. When selecting the tolerance class, the respective customary workshop accuracy has to be taken into consideration.
3. Smaller or larger tolerances should be indicated adjacent to the relevant nominal dimensions.
4. General tolerances specified in angular units control only the general orientation of lines or line elements of surfaces, but not their form deviations.
Iso 2768 Mk Meaning
5. If general tolerances in accordance with ISO 2768 shall apply, the information shall be indicated in or near the title block, such as ISO 2768-m.