General Tolerance Iso 2768-mk Guide
If you are currently working on a manufacturing blueprint, tell me:
Perpendicularity controls the 90-degree relationship between two intersecting surfaces or axes. It uses the longer of the two intersecting sides as the baseline reference length. Reference Length Range (mm) Tolerance Class (Medium) over 100 to 300 over 300 to 1000 over 1000 to 3000 3. Symmetry
While the "m" part dictates size, the "k" part dictates form and position. ISO 2768 Part 2 ensures that parts are straight, flat, and perpendicular enough to function correctly, even if specific Geometric Dimensioning and Tolerancing (GD&T) symbols are missing from the drawing. Straightness and Flatness
Refers to ISO 2768-1 , which governs linear and angular dimensions (like lengths, radii, and diameters). general tolerance iso 2768-mk
While the 'm' class controls the size of a feature, the 'K' class in ISO 2768-2 ensures its geometric quality. These tolerances are critical for ensuring that mating parts fit and function correctly, and that rotating components operate without vibration or binding. The 'K' class represents a medium precision level for form and position.
2. Tolerances for Broken Edges (External Radii and Chamfers)
If your drawing title block says "ISO 2768-mK," but you explicitly label a critical slot as 20.00mm +0.02 / -0.00 , the manufacturer must prioritize the +0.02mm limit for that slot while applying the standard ISO ±0.2mm tolerance to the rest of the part. Conclusion If you are currently working on a manufacturing
In mechanical engineering and manufacturing, clear communication between designers and machinists is critical. If every single dimension on a technical drawing required an explicit tolerance, the blueprint would become an unreadable cluster of numbers. To solve this problem, the International Organization for Standardization developed .
Refers to Part 2 of the standard, covering Geometrical tolerances (like flatness, symmetry, and run-out). The 'k' is the class for general geometrical tolerances. ISO 2768-1: Linear Dimensions (The 'm')
Under ISO 2768-1, there are four tolerance classes: f (fine), m (medium), c (coarse), and v (very coarse). The class is the most frequently used in general mechanical engineering. Linear Dimensions (mm) Symmetry While the "m" part dictates size, the
Aerospace or automotive engine components often require strict geometric limits (Class H or custom GD&T) to prevent mechanical failure. ✅ Summary of ISO 2768-mK
The standard is split into two parts:
