Iso 2768 General Tolerances Pdf Exclusive |verified| Jun 2026
: Used for parts where high precision is not required.
| Class | Designation | Description | Typical Application | | :--- | :--- | :--- | :--- | | | Fine | Highest precision among the classes. | Precision instruments, tight fits, high-cost components. | | m | Medium | The industry standard. Most drawings use this. | General CNC machining, turning, and milling. | | c | Coarse | Loose tolerances for non-critical features. | Castings, rough forgings, or parts where fit isn't crucial. | | v | Very Coarse | The loosest manufacturing tolerances. | Sheet metal fabrication and coarse structural components. |
The protocol is split into two primary segments to cover dimensional attributes and shape profiles:
: Covers geometrical tolerances for features (such as straightness, flatness, perpendicularity, and symmetry). ISO 2768-1: Linear and Angular Dimensions
Workshops know exactly what level of accuracy is expected based on standard workshop capabilities. Structure of the ISO 2768 Standard iso 2768 general tolerances pdf exclusive
| Nominal Length Range (mm) | f (Fine) | m (Medium) | c (Coarse) | v (Very Coarse) | | :--- | :--- | :--- | :--- | :--- | | 0.5 up to 3 | ±0.05 | ±0.1 | ±0.2 | — | | over 3 up to 6 | ±0.05 | ±0.1 | ±0.3 | ±0.5 | | over 6 up to 30 | ±0.1 | ±0.2 | ±0.5 | ±1.0 | | over 30 up to 120 | ±0.15 | ±0.3 | ±0.8 | ±1.5 | | over 120 up to 400 | ±0.2 | ±0.5 | ±1.2 | ±2.5 | | over 400 up to 1000 | ±0.3 | ±0.8 | ±2.0 | ±4.0 | | over 1000 up to 2000 | ±0.5 | ±1.2 | ±3.0 | ±6.0 | | over 2000 up to 4000 | — | ±2.0 | ±4.0 | ±8.0 |
Permissible deviations in mm for nominal size ranges.
ISO 2768-2 establishes three tolerance classes: , K , and L . Straightness and Flatness
These values restrict how much a flat surface or a straight line can warp or bow over its length. Tolerance Class Up to 10mm over 10 to 30mm over 30 to 100mm over 100 to 300mm over 300 to 1000mm over 1000 to 3000mm K L 2. Perpendicularity : Used for parts where high precision is not required
Most general mechanical engineering applications utilize the "m" (medium) class.
Workshops understand the required workshop accuracy immediately, preventing over-processing of non-critical parts. ISO 2768 Part 1: Linear and Angular Dimensions
Truth: The standard explicitly assumes normal rigidity. For rubber, soft aluminum (1100 series), or thin-walled titanium, the standard’s "Fine" tolerance is impossible to hold without custom fixtures.
Tolerance Values for External Radii and Chamfer HeightsThese are typically tighter to ensure fit and finish:For 0.5 to 3 mm, the tolerance is ±0.2 mm.Over 6 mm, the tolerance is ±0.5 mm. ISO 2768-2: Geometrical Tolerances | | m | Medium | The industry standard
These values apply strictly to the rounding or beveling of sharp edges. Nominal Size Range (mm) Class f (Fine) (mm) Class m (Medium) (mm) Class c (Coarse) (mm) Class v (Very Coarse) (mm) Over 3 to 6 Over 6 Angular Dimensions
To enforce these tables on your project, you must look at or add a note to the technical drawing title block. The format combines the lowercase letter from Part 1 with the uppercase letter from Part 2.
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Disclaimer: This article provides a summary of the ISO 2768 standards. Always refer to the full, official ISO documentation for complete technical specifications. If you'd like, I can: