When you specify "ISO 2768-m," you are telling the shop that a 100mm block can be between 99.8mm and 100.2mm (depending on the nominal size range). Below is the tolerance table for Class "m":
Under ISO 2768-2, there are three tolerance classes for general geometrical tolerances: K (Medium) L (Low) Tolerance Iso 2768 Mk Pdf
| Nominal Size Range | Tolerance (mm) | |--------------------|----------------| | 0.5 to 3 | ±0.1 | | >3 to 6 | ±0.1 | | >6 to 30 | ±0.2 | | >30 to 120 | ±0.3 | | >120 to 400 | ±0.5 | | >400 to 1000 | ±0.8 | | >1000 to 2000 | ±1.2 | When you specify "ISO 2768-m," you are telling
This letter refers to Part 2 of the standard, which covers features like straightness, flatness, and circularity. The "k" represents a specific tolerance class for these geometric characteristics. Other classes in Part 2 include 'H' and 'L'. Key Components of the Standard Other classes in Part 2 include 'H' and 'L'
In simple terms: If a dimension on a drawing does not have a specific tolerance written next to it, the rules of ISO 2768 automatically apply.