General Tolerance Iso 2768-mk -
However, the selection of the 'mk' class over others (like 'f' for fine, 'c' for coarse, or 'v' for very coarse) carries significant implications for manufacturing. While 'mk' is the most common default, it is not a "one-size-fits-all" solution. The 'medium' linear tolerance (m) is surprisingly tight for very large parts, where a ±0.5 mm swing is negligible, and surprisingly loose for miniature precision components. The 'k' geometric tolerance demands that features remain within a specific envelope of flatness or perpendicularity. For example, a large milled plate 500 mm long under ISO 2768-mk would require a flatness of 0.5 mm. This is achievable with standard milling but would be impossible with basic saw cutting.
In the intricate world of technical design and manufacturing, a drawing is more than a picture; it is a legal contract between the designer and the machinist. Every line, dimension, and note carries a specific command. However, specifying tight tolerances for every single feature of a part would be financially ruinous and technically unnecessary. To solve this dilemma, engineers rely on a silent shorthand: general tolerances . Among the most widely adopted standards for this purpose is ISO 2768-mk , a code that dictates the allowable limits of variation for dimensions and geometries when no explicit tolerance is given. general tolerance iso 2768-mk
Where ISO 2768-mk truly shines is in its role as a . It forces designers to be intentional. When an engineer applies this general tolerance, they are effectively stating: "All features that do not have a specific tolerance block are assumed to be non-critical, and the 'medium' workshop accuracy is acceptable." If a feature requires greater precision—such as a bearing seat or a guide rail—the designer must explicitly call out a tighter tolerance (e.g., H7 or g6), which overrides the general standard. This distinction separates critical control points from the "background noise" of the part, clarifying priorities for quality control inspectors and machinists alike. However, the selection of the 'mk' class over