Iso 2768-mh Tolerance Chart
General tolerances on circular run-out Unit : mm Tolerance class H K L Circular run-out tolerance 0.1 0.2 0.5. General Tolerances to DIN ISO 2768 - DAU Components
| Nominal Size Range (mm) | Tolerance (mm) | |------------------------|----------------| | ≤ 100 | 0.2 | | >100 to 300 | 0.3 | | >300 to 1000 | 0.4 | | >1000 to 3000 | 0.5 |
What you are using (CNC machining, sheet metal, 3D printing?) The material of your part (aluminum, steel, plastics?)
| Nominal Size Range (mm) | Tolerance Class | | :--- | :--- | | | m (Medium) | | 0.5 up to 3 | ±0.2 | | over 3 up to 6 | ±0.5 | | over 6 | ±1 | iso 2768-mh tolerance chart
Refers to Part 1 of the standard, covering linear and angular dimensions (e.g., lengths, diameters, radii).
ISO 2768 simplifies drawing tolerancing by defining default tolerances applicable where no specific tolerance is provided. It reduces drawing clutter, promotes consistent interpretation, and helps control manufacturing costs by assigning broader or tighter tolerances depending on acceptable variability. The standard covers two parts: ISO 2768‑1 (general tolerances — linear and angular dimensions without individual tolerance indications) and ISO 2768‑2 (geometrical tolerances). Within ISO 2768‑1, four tolerance grades are specified: fine (f), medium (m), coarse (c), and very coarse (v). “m” (medium) is the default commonly used for general mechanical engineering where moderate precision is required.
The "m" class defines permissible deviations for linear measurements, external sizes, internal sizes, steps, diameters, and radii. The tolerance ranges strictly depend on the nominal size of the dimension. Larger dimensions naturally receive wider allowances. Linear Dimensions Tolerance Table (Class m) Nominal Size Range (mm) Tolerance Limit (mm) 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 Broken Edges Tolerance Table (Class m) General tolerances on circular run-out Unit : mm
6 — 30: ±0.2
When you see "ISO 2768-mH", the indicates that the "medium" class is applied to all linear dimensions (like lengths, widths, diameters) and angular dimensions that do not have an explicit tolerance.
When you see on a technical drawing, it means that unless otherwise specified, the workshop must adhere to the Medium linear tolerances and High (h) geometric tolerances listed above. This approach reduces drafting time and clarifies which dimensions are critical versus standard. “m” (medium) is the default commonly used for
Tolerance (grade m) for length L (mm):
Permissible deviations for broken edges, external radii, and chamfer heights for the "m" (medium) class.
"If I write ISO 2768-mh, I never have to tolerance diameters." Reality: Diameters (like a Ø10mm hole) follow the SAME linear chart. A Ø10mm hole could be Ø10.2mm. That is an H11 tolerance loose fit. For a running fit, you still need an explicit H7 or G6.
The following tables contain the exact values used to inspect and manufacture parts under the ISO 2768-mh standard. All values are listed in millimeters (mm). 1. Linear Dimensions (Class m - Medium)