| Nominal Dimension Range (mm) | Permitted Deviation (± mm) | |------------------------------|----------------------------| | 0.5 up to 3 | ±0.1 | | >3 up to 6 | ±0.1 | | >6 up to 30 | ±0.2 | | >30 up to 120 | ±0.3 | | >120 up to 400 | ±0.5 | | >400 up to 1000 | ±0.8 | | >1000 up to 2000 | ±1.2 | | >2000 up to 4000 | ±2.0 |
✅ Example: A 50 mm width without a specific tolerance is allowed to be 50 mm ±0.3 mm.
To understand the "mh" combination, one must first understand the parent standard, ISO 2768. It is divided into two parts: iso 2768-mh tolerance chart
Thus, the notation "ISO 2768-mh" instructs the manufacturer to apply the 'm' (medium) class from Part 1 for linear/angular dimensions, and the 'h' (fine) class from Part 2 for geometrical tolerances.
| Tolerance Class | Straightness & Flatness (mm) | Perpendicularity (mm) | Symmetry (mm) | Circular Runout (mm) | | :--- | :--- | :--- | :--- | :--- | | H (Medium) | 0.2 per 100mm length | 0.3 per 100mm length | 0.5 | 0.2 | | Nominal Dimension Range (mm) | Permitted Deviation
Interpretation of Table 2:
The existence of this chart does not mean you should never add explicit tolerances. To understand the "mh" combination, one must first
Do not use ISO 2768-mh for: