2. Tolerances for Broken Edges (External Radii and Chamfers)
Quality inspectors know exactly what baseline standard to judge the parts by, allowing for faster component sign-offs. How to Indicate ISO 2768-mK on a Drawing
Perpendicularity defines the allowable deviation from a perfect 90-degree angle between two planes or axes. 0.4 mm max deviation. Over 100 to 300 mm: 0.6 mm max deviation. Over 300 to 1000 mm: 0.8 mm max deviation. Over 1000 to 3000 mm: 1.0 mm max deviation. Symmetry and Run-Out general tolerance iso 2768-mk
: Represents the K tolerance class for geometrical tolerances (form and position characteristics like straightness, flatness, perpendicularity, and symmetry).
When manufacturing a mechanical part, achieving absolute perfection in dimensions is physically impossible. Minor variations always occur due to tool wear, machine vibrations, and material expansion. To ensure parts fit together without requiring expensive, hyper-precise measurements for every single dimension, engineers use general tolerances. Over 1000 to 3000 mm: 1
If your assembly has a critical mating part—such as a bearing press-fit or a sealed O-ring groove—the general tolerances of ISO 2768-mk will likely be too loose. In these scenarios, you must (e.g., or a fit callout like
The "K" class defines how much a feature can deviate in shape or position. These are critical for ensuring parts fit together during assembly. Straightness and Flatness In these scenarios
: Removes messy individual tolerance callouts from non-critical features.
These values are determined by choosing the longer of the two surface lengths or the diameter of the cylindrical part. Nominal Length Range (mm) Straightness & Flatness Tolerance (mm) for Class "k" Over 10 to 30 Over 30 to 100 Over 100 to 300 Over 300 to 1000 Over 1000 to 3000 2. Perpendicularity