General Tolerance Iso 2768-mk [verified] < 2025-2027 >

Here is the real-world data for ISO 2768-mk. Use this to decide if your design needs tighter tolerances.

Geometrical tolerances control form, orientation, and run-out. The class enforces medium control over these geometric features. Straightness and Flatness

Choosing the correct tolerance class is a critical design decision that directly impacts manufacturing cost and feasibility.

Therefore, when you see in a drawing title block, it means the component must be manufactured to Medium linear tolerances and Medium geometric tolerances . ISO 2768-m (Part 1): Linear and Angular Dimensions general tolerance iso 2768-mk

Any tolerance written explicitly next to a dimension automatically overrides ISO 2768-mK. Use explicit tolerances for critical fits, bearing seats, and tight assembly clearances.

Linear dimensions include external sizes, internal sizes, steps, diameters, and distances. Nominal Size Range (mm) Permissible Deviation (mm) for Class Over 3 to 6 Over 6 to 30 Over 30 to 120 Over 120 to 400 Over 400 to 1000 Over 1000 to 2000 Over 2000 to 4000 External Radii and Chamfer Heights

Section B (using table) 6. Ø10 mm: a) m: ±0.15 → range 9.85–10.15 mm b) k: ±0.5 → range 9.5–10.5 mm 7. Length 45 mm: a) m: for 30–120 → ±0.2 → 44.8–45.2 mm b) k: for 30–120 → ±0.8 → 44.2–45.8 mm 8. Ø2.5 mm: a) m (≤3) ±0.1 → 2.4–2.6 mm b) k (≤3) ±0.3 → 2.2–2.8 mm 9. Angle 60°: m: ±1.0° → 59.0°–61.0° k: ±3.0° → 57.0°–63.0° If groove requires ±0.05 mm explicit tolerance, that explicit tolerance overrides ISO 2768 for that feature and ISO 2768 does not apply to that groove. Here is the real-world data for ISO 2768-mk

The "m" component of ISO 2768-mK governs linear distances. In manufacturing, larger parts naturally require larger permissible deviations. Therefore, the standard breaks down acceptable deviations into specific nominal dimension ranges. Linear Dimensions

While ISO 2768 has been the trusted backbone of manufacturing for decades, modern global drafting practices are transitioning toward and updated Geometric Dimensioning and Tolerancing (GD&T) principles under ASME Y14.5. These newer standards implement general geometric specifications to better control 3D component spaces. However, ISO 2768-mk remains the most widely recognized standard in European CNC machining and traditional fabrication workshops. ✅ Conclusion

This part controls the "form" of the part. For example, "K" ensures a surface stays reasonably flat or straight without needing a specific GD&T callout for every face. The General CNC Machining Tolerance: ISO 2768-mk The class enforces medium control over these geometric

Extra credit

Angular tolerances are not constant; they depend on the length of the shorter side of the angle.

The designation is split into two distinct parts, covering different aspects of manufacturing accuracy: