ISO 2768 is an essential tool for mechanical designers and manufacturers. By understanding and utilizing the f , m , c , and v classes in ISO 2768-1, and the H , K , L classes in ISO 2768-2, you can streamline your design process and ensure high-quality, cost-efficient production.
While Part 1 handles lengths and angles, controls the shape, form, and position of features. These are known as geometrical tolerances (similar to standard GD&T controls).
"Look here," Elias pointed to a table. "People think general tolerances are just laziness—a way to avoid marking every single dimension on a drawing. But it’s actually a secret language of trust between the designer and the shop." iso 2768 general tolerances pdf exclusive
The standard is explicitly split into two complementary parts that govern separate aspects of a component's physical geometry:
| Nominal Length Range (mm) | Class H | Class K | Class L | |--------------------------:|:-------:|:-------:|:-------:| | ≤ 100 | 0.5 | 0.6 | 0.6 | | >100 – 300 | 0.5 | 0.6 | 1.0 | | >300 – 1000 | 0.5 | 0.8 | 1.5 | | >1000 – 3000 | 0.5 | 1.0 | 2.0 | ISO 2768 is an essential tool for mechanical
Establishes a universal language between design firms and external manufacturing vendors worldwide. Industry Transition Note
A significant aspect of ISO standards, including ISO 2768, is their legal status. Unlike national laws or regulations which are public domain, ISO standards are copyrighted documents developed by a non-governmental organization. This leads to the concept of "exclusive" distribution. These are known as geometrical tolerances (similar to
To legally enforce general tolerances, the drawing title block must feature a specific note. The note must clearly state the standard designation followed by the chosen tolerance classes from both Part 1 and Part 2. ISO 2768 - [Part 1 Class][Part 2 Class]