If you work in mechanical design or manufacturing, you’ve likely seen the notation "ISO 2768-mH" on a drawing title block.
| Shorter Side Length (mm) | Tolerance (mm) | |--------------------------|----------------| | ≤ 100 | 0.2 | | >100 to 300 | 0.3 | | >300 to 1000 | 0.4 | | >1000 to 3000 | 0.5 |
Cost Efficiency: Use these general tolerances for non-critical features to avoid over-engineering and high machining costs. iso 2768-mh tolerance chart
ISO 2768-mh tolerance chart is a standardized system used in mechanical engineering to simplify technical drawings by defining general tolerances for linear and geometrical dimensions without specific indications. The designation "mH" refers to a combination of two specific precision classes: (Medium) for linear and angular dimensions and for geometrical tolerances (form and position). Overview of ISO 2768
The ISO 2768-MH tolerance chart is a specific part of the ISO 2768 standard, which defines the tolerances for medium (M) and high (H) accuracy classes. The chart provides a set of tolerance values for different feature types, including: Title: Decoding the ISO 2768-mH Tolerance Chart: When
These tolerances apply to measurements like lengths, widths, diameters, and step distances. Nominal Dimension Range (mm) Tolerance (± mm) Over 3 to 6 Over 6 to 30 Over 30 to 120 Over 120 to 400 Over 400 to 1,000 Over 1,000 to 2,000 Over 2,000 to 4,000 Xometry Standard Tolerances Geometrical Tolerances (H - High Precision)
Conclusion
While powerful, the ISO 2768-mh chart is not a universal panacea. Engineers must apply it with intelligence.
Myth: "The 'H' means the same as the 'm'." Reality: No. 'H' is specifically from ISO 2768-2. It defines geometry, not size. A part can be the wrong size (within 'm') but perfectly flat (within 'H'). The designation "mH" refers to a combination of