When a designer writes ISO 2768-MK-E in the title block or general notes of a drawing, it instructs the manufacturer that must conform to the specific limits defined by this standard.
If a feature matters for function or fit, give it an explicit tolerance. ISO 2768-MK-E is for everything else. iso 2768-mk-e
GENERAL TOLERANCES: ISO 2768-MK-E Alternatively: When a designer writes ISO 2768-MK-E in the
These values apply per 100 mm of length. For longer lengths, the tolerance is prorated but limited by the maximum deviation. For designers, using it correctly (and knowing its
| Tolerance Class | Straightness & Flatness (mm per 100 mm) | Perpendicularity & Symmetry (mm per 100 mm) | Runout (mm) | |----------------|------------------------------------------|----------------------------------------------|--------------| | | 0.2 | 0.5 | 0.2 |
For production shops, understanding this shorthand reduces errors and clarifies expectations. For designers, using it correctly (and knowing its limits) produces clear, manufacturable drawings without over-tolerancing.
1. Introduction ISO 2768-MK-E is a combined shorthand notation used on engineering drawings and technical documents. It references three parts of the ISO 2768 standard, which specifies default tolerances for linear dimensions, angular dimensions, geometrical features (form, orientation, location, and runout), and the indication of "E" for general external radius and chamfer dimensions.