If you are designing custom mechanical enclosures, structural brackets, or general machinery parts, assigning provides the ideal balance of precision and manufacturability for standard industrial processes.
This defines how much a feature can deviate from being exactly 90 degrees to a reference surface.
ISO 2768 is an international standard that defines general tolerances for linear and angular dimensions, as well as geometric tolerances for features without individual tolerance indications. It simplifies technical drawings by eliminating the need to specify tolerances for every single dimension. is a combination of two parts of the standard:
Instead of cluttering a drawing with ±0.1mm for every hole or slot, you write the standard once in the title block. This tells the workshop: “If no specific tolerance is shown next to a dimension, follow this table.” general tolerance iso 2768-mk
The second letter refers to (Geometric tolerances). The classes are H, K, L .
The tolerance value depends on the length of the line (for straightness) or the length of the longer side (for flatness).
The notation "ISO 2768-mK" references two distinct parts of the ISO 2768 standard, applying different classes to different types of measurements. It simplifies technical drawings by eliminating the need
For features like fillets and broken edges, the permissible deviations differ from standard linear dimensions. These values also apply to chamfer heights.
Symmetry tolerances apply to features sharing a common median plane. Nominal Length Range ( Tolerance Limit for Class "K" ( 4. Circular Run-out
| 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 | The classes are H, K, L
When a design requires higher precision, a different standard can be selected.
It ensures that a machine shop in one country interprets "no tolerance" the same way as a shop in another. Part 1: Dimensional Tolerances (The "m")
Answer key (concise) — for examiner use only