Iso 2768-mh Tolerance Chart

If you design a shaft with a length of 50mm and do not write a tolerance, ISO 2768-mh applies. Looking at the chart, 50mm falls into the ">30 up to 120" row. Therefore, the acceptable length is 50mm ±0.3mm (49.7mm to 50.3mm). Angular Dimensions (ISO 2768-m) Angles are treated slightly differently. For Class 'm', the tolerance is expressed in millimeters per millimeter of the shorter side.

| Class | Linear (6-30mm) | Geometric (Flatness per 100mm) | Typical Application | | :--- | :--- | :--- | :--- | | | ±0.05mm | 0.1mm | Precision instruments, aerospace backups | | m (Medium) | ±0.2mm | 0.2mm | General machining, welding fixtures | | c (Coarse) | ±0.5mm | 0.4mm | Sand castings, agricultural equipment | | v (Very Coarse) | ±1.0mm | 0.8mm | Rough fabrications, concrete molds | iso 2768-mh tolerance chart

ISO 2768-mH Alternatively (for clarity): General tolerances according to ISO 2768-1 (Class m) and ISO 2768-2 (Class H). What to avoid: Do not write just "Tolerances: mH" without referencing ISO 2768. The standard implies specific rules for radii, chamfers, and how to treat zero values. Radii and Chamfers Under ISO 2768-m A frequently overlooked part of the standard concerns external radii (r) and chamfer heights. If you design a shaft with a length

The 'H' grade corresponds to the "Medium" geometric class. Here is the for geometry: Table 2: ISO 2768-2 'H' Grade (Medium) 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 | Angular Dimensions (ISO 2768-m) Angles are treated slightly

Among the four tolerance classes (f – fine, m – medium, c – coarse, v – very coarse), one stands out as the undisputed king of job shops, prototype development, and general machinery: .

'f' is too expensive for base material. 'c' is too loose for mating holes. 'mH' balances cost and functionality for 80% of mechanical parts. When NOT to Use ISO 2768-mh The existence of this chart does not mean you should never add explicit tolerances.