These tolerances are usually applied when no specific tolerances are given for certain features. The standard provides a general guideline for acceptable variations in dimensions and geometry, to ensure that parts can be manufactured and assembled properly.
| Nominal Length Range (mm) | Straightness / Flatness (mm) – H | |---------------------------|----------------------------------| | Up to 10 | 0.02 | | >10 to 30 | 0.05 | | >30 to 100 | 0.1 | | >100 to 300 | 0.2 | | >300 to 1000 | 0.3 | | >1000 to 3000 | 0.4 | iso 2768 m h
| Component Type | Suitability of ISO 2768-mH | Remarks | |----------------|-----------------------------|---------| | Machined bracket (cast iron) | Highly suitable | Class m (±0.3 mm up to 120 mm) matches typical milling. Class H flatness (0.1 mm for 100 mm) is feasible. | | Plastic injection molded part | Not recommended | Shrinkage and warpage exceed m tolerances; use part-specific tolerances (e.g., ISO 20457). | | Sheet metal chassis (laser cut) | Suitable for non-critical holes | Bend angles may exceed angular tolerance of m (±0.5°); specify individual angular tolerances for folds. | | Precision shaft (diameter 20 mm) | Not suitable for bearing fit | General tolerance ±0.2 mm is too loose for H7/g6 fit; requires individual tolerance. | These tolerances are usually applied when no specific