When applying ISO 2768 general tolerances, keep these practical points in mind:
Machinists can work faster when tighter tolerances are not required. 6. How to Apply ISO 2768-mK on Drawings
This combination is one of the most popular in the industry because it provides a good balance between manufacturing cost and precision. For most standard CNC-machined or sheet metal parts, ISO 2768-mK offers an acceptable level of accuracy without over-specifying requirements. For instance, a hole diameter of 10mm under the "m" class would have a tolerance of ±0.2 mm.
By combining them into "Mk," a manufacturer knows to look at the "Medium" tolerance tables for both linear dimensions and geometric relationships. ISO 2768-1: Linear and Angular Tolerances (Class m) Tolerance Iso 2768 Mk Pdf
: Covers geometrical tolerances for features like straightness, flatness, perpendicularity, symmetry, and circular run-out. It features three tolerance classes: H, K, and L.
| Feature | Standard | Tolerance Class | | :--- | :--- | :--- | | Linear and Angular Dimensions | ISO 2768-1 (General Tolerances) | f (Fine), m (Medium), c (Coarse), v (Very Coarse) | | Geometrical Tolerances (Straightness, Flatness, Perpendicularity, Symmetry, Run-out) | ISO 2768-2 (Geometrical Tolerances) | H, K, L |
is the backbone of modern mechanical drawing interpretation. It prevents arguments between design and manufacturing. It saves money by allowing standard tolerances on non-critical features. When applying ISO 2768 general tolerances, keep these
provides a one-page lookup for "m" (medium) and other classes. Summary Tables for ISO 2768-mK
This is where comes into play. Specifically, the combination ISO 2768-mK is arguably the most common general tolerance standard used in global CNC machining, 3D printing, and sheet metal fabrication.
For rotating elements, the general circular run-out tolerance for class K is 0.2 mm . Why Use ISO 2768-Mk in Manufacturing? For most standard CNC-machined or sheet metal parts,
1. The "m" Class: Linear and Angular Dimensions (ISO 2768-1)
Similar tables exist for perpendicularity, symmetry, and circular run-out. For example, the general tolerance for perpendicularity under class K might be 0.4 mm for a length range of 100-300 mm, and the run-out tolerance for class K is often 0.2 mm.
For example, instead of specifying a tolerance for every hole, shaft, and edge radius on a complex part, simply writing "ISO 2768-mK" in the title block informs the machinist that all untoleranced dimensions are subject to the standard’s defined limits. This standard is the dominant general tolerance standard in Europe and Asia and is widely recognised by CNC machining suppliers worldwide. ISO 2768 supersedes older national standards like the original DIN 7168 and is crucial for international collaboration.
This single line replaces dozens of individual tolerance boxes, cleans up the drawing, and clearly defines the acceptable limits for the manufacturer.
Reduces clutter by eliminating the need to mark every dimension.