Tolerance Iso 2768-mk — General

The goal is simple: to simplify drawings. By referencing ISO 2768, a designer tells the machinist, "Unless I specify otherwise, follow these standard accuracy levels." Breaking Down the "mk" Suffix

Parts made from plastics or materials with high thermal expansion (the standard is primarily designed for metal removal/machining). Dimensions where safety or critical function is at stake.

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) general tolerance iso 2768-mk

The designation consists of two separate parts that define the accuracy level for different features:

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') The goal is simple: to simplify drawings

For the 'm' class, the allowable deviation depends on the size of the dimension: Nominal Size (mm) Tolerance (± mm) 120 to 400 400 to 1000 External Radii and Chamfer Heights Nominal Size (mm) Tolerance (± mm) ISO 2768-2: Geometrical Tolerances (The 'k')

In the world of precision manufacturing, specifying every single dimension with a dedicated tolerance would make technical drawings cluttered and nearly impossible to read. To solve this, engineers use general tolerance standards. The most common among these is . Under ISO 2768-1, there are four tolerance classes:

ISO 2768-mk is the "Goldilocks" of manufacturing tolerances—not too tight, not too loose. It ensures that parts are functional and interchangeable without unnecessary manufacturing expenses. When you see it on a drawing, you’re looking at a standard of and Medium Geometrical control .

Part 2 focuses on the "form" of the part. There are three classes: H, K, and L. The class is the medium-level requirement for geometry.

For a side up to 100mm, the limit is 0.4mm.