The notation combines two different tolerance classes.

| Class | Linear (mm for 30–120 mm) | Geometrical (Flatness for 30–100 mm) | Typical Use | |-------|----------------------------|---------------------------------------|--------------| | (fine) | ±0.15 | 0.05 | Precision machining | | m (medium) | ±0.30 | 0.10 | Standard machined parts | | c (coarse) | ±0.50 | 0.20 | Fabrication, welding | | v (very coarse) | ±1.00 | 0.50 | Castings, rough sawn |

: Ranges from 0.05 mm for small parts to 0.6 mm for parts over 1000 mm long. Perpendicularity

| Code | Refers to | Tolerance Class | Typical Application | |------|-----------|----------------|---------------------| | | ISO 2768-1 (Linear/Angular) | Medium | General machining (lathe, mill, drilling) | | k | ISO 2768-2 (Geometrical) | Fine | Tighter form & position control |

The designation combines two separate parts of the ISO 2768 standard: