The ISO 2768-mh standard is a specific designation within the international manufacturing framework used to simplify technical drawings by providing general tolerances for parts produced by machining or metal removal .
Cleaner Drawings: You don't have to clutter your CAD exports with "±" values for every single fillet or shoulder. iso 2768-mh tolerance chart
Interpretation: A 200 mm long surface must be flat within 0.2 mm. A hole's axis must be perpendicular to a reference surface within a 0.1 mm cylindrical zone if the feature size is between 30-100 mm. The ISO 2768-mh standard is a specific designation
Applications of ISO 2768-MH
The ISO 2768-mh tolerance chart is a masterclass in engineering standardization—a compact, intelligent, and widely accepted tool that balances the competing demands of precision, cost, and clarity. By mandating a 'medium' flexibility on linear sizes and a 'fine' discipline on geometric form, it provides a sensible default for countless general machining applications, from mounting brackets to simple enclosures. However, its very convenience is its greatest risk. The chart is a starting point, not a finish line. The responsible engineer must recognize when to override the default, applying specific calculated tolerances for critical fits, evaluating the compatibility of the 'm' and 'h' classes with the chosen manufacturing process, and always, always considering the real-world function of the part. Mastery of ISO 2768-mh lies not in memorizing its numbers, but in understanding the profound engineering judgment that dictates when to apply it, and when to draw a red circle and specify a tighter, functional tolerance. In that judgment, the chart transcends its role as a table of numbers and becomes a true design philosophy. ISO 2768-1 (1990): Tolerances for linear and angular
This is where ISO 2768 comes into play. It is the international savior that defines "general tolerances" for linear and angular dimensions without individual tolerance indications.