The K class tolerance equals the flatness tolerance for the shorter side of the angle.
Scope and structure ISO 2768 is published in parts. The most commonly referenced part for general dimensional tolerances is ISO 2768‑1: “General tolerances — Part 1: Tolerances for linear and angular dimensions without individual tolerance indication.” There is also ISO 2768‑2: “Geometrical tolerances.” ISO 2768‑1 defines tolerance classes (finer to coarser) that apply to linear and angular dimensions: m (medium), c (coarse), and v (very coarse). Each class assigns tolerance values depending on the nominal size range of the feature. ISO 2768‑2 supplements this by giving guidance on permissible geometric deviations (such as flatness, perpendicularity, coaxiality) when specific geometric tolerances are not shown.
