General Tolerance Iso 2768-mk -

These control the acceptable variance in angular degrees based on the length of the shorter leg of the angle. Length of Shorter Leg (mm) Tolerance Deviation for Class "m" ±plus or minus 1∘1 raised to the composed with power Over 10 to 50 ±plus or minus Over 50 to 120 ±plus or minus Over 120 to 400 ±plus or minus ±plus or minus ISO 2768-2: The "k" Class (Geometrical Tolerances)

| Nominal Length Range | Tolerance (mm) | |----------------------|----------------| | ≤ 10 | 0.02 | | >10 – 30 | 0.05 | | >30 – 100 | 0.1 | | >100 – 300 | 0.2 | | >300 – 1000 | 0.3 | | >1000 – 3000 | 0.4 |

While ISO 2768-mk is easily achievable for metals like aluminum and steel via CNC milling, it can be extremely difficult to maintain on soft plastics, rubbers, or 3D-printed parts due to thermal expansion and warping.

The first letter refers to (Linear & Angular tolerances). There are four classes: general tolerance iso 2768-mk

The industry standard for general mechanical engineering and machining.

"Medium" (m) and "K" classes represent standard workshop accuracy. Forcing tighter tolerances where they aren't needed increases manufacturing time and cost.

Instead of writing ± values for every single hole or edge, one note covers everything non-critical. These control the acceptable variance in angular degrees

If your assembly has a critical mating part—such as a bearing press-fit or a sealed O-ring groove—the general tolerances of ISO 2768-mk will likely be too loose. In these scenarios, you must (e.g., or a fit callout like

If a specific dimension has an explicit tolerance written next to it (e.g., 50mm ±0.02 ), the specific tolerance overrides ISO 2768-mK.

ISO 2768-mK is an international standard that defines general tolerances for machining processes, such as CNC machining . It is typically indicated in the drawing's title block as "General Tolerance: ISO 2768-mK". There are four classes: The industry standard for

For class , the general tolerance for circular run-out (radial, axial, and any surface of revolution) is 0.2 mm . Why Use ISO 2768-mK?

| Length of Shorter Side (mm) | Tolerance (± degrees/minutes) | | :--- | :--- | | Up to 10 | ± 1° | | Over 10 up to 50 | ± 0° 30' | | Over 50 up to 120 | ± 0° 20' | | Over 120 up to 400 | ± 0° 10' | | Over 400 | ± 0° 5' |