The standard ISO 2768 provides the following key features:
Many engineers fall into the trap of using a faded, photocopied chart from 1995. This is dangerous. The version of the ISO 2768 general tolerances PDF contains critical footnotes, boundary conditions, and updates regarding nominal size ranges.
These values define the allowable angular variation based on the length of the shorter leg of the angle in question. Tolerance Class Up to 10mm 10 to 50mm 50 to 120mm 120 to 400mm Over 400mm (Fine) m (Medium) c (Coarse) v (Very Coarse) ISO 2768-2: Geometrical Tolerances Tables
Eliminates clutter caused by repetitive tolerance callouts. iso 2768 general tolerances pdf exclusive
ISO 2768 is an international manufacturing standard that simplifies technical drawings by establishing default "general tolerances" for dimensions and features that do not have individual tolerance callouts. Instead of annotating every single measurement, engineers can simply reference this standard in the drawing's title block—most commonly as —to define acceptable variations. Why Use ISO 2768?
Most general mechanical engineering applications utilize the "m" (medium) class.
For a complete set of tables including angularity and run-out, you can access these technical PDF guides from industry leaders: ISO 2768 Full Guide Dimensional Tolerance Chart Comprehensive Machining PDF DAU Components perpendicularity ISO 2768-2 The standard ISO 2768 provides the following key
120 to 400mm: ±0.5mm
The tolerance is given in mm per the length of the feature. For a 200mm long block with class "m," the flatness tolerance is 0.5mm.
Angular deviations are measured based on the length of the shorter leg of the angle. Length of Shorter Leg (mm) Medium (m) Coarse (c) Very Coarse (v) Over 10 to 50 Over 50 to 120 Over 120 to 400 Over 400 ISO 2768-2: Geometrical Tolerances These values define the allowable angular variation based
| Nominal Length Range (mm) | Class H | Class K | Class L | |--------------------------:|:-------:|:-------:|:-------:| | ≤ 10 | 0.02 | 0.05 | 0.1 | | >10 – 30 | 0.05 | 0.1 | 0.2 | | >30 – 100 | 0.1 | 0.2 | 0.4 | | >100 – 300 | 0.2 | 0.4 | 0.8 | | >300 – 1000 | 0.3 | 0.6 | 1.2 | | >1000 – 3000 | 0.4 | 0.8 | 1.6 |
Covers features that do not have individual geometrical tolerances (such as straightness, flatness, perpendicularity, and symmetry). Part 1: ISO 2768-1 (Linear & Angular Tolerances)
ISO 2768-mH (Linear class "m", Geometrical class "H")
Understanding ISO 2768: The Definitive Guide to General Tolerances
| Nominal Length Range | H (Precision) | K (Standard) | L (Coarse) | | :--- | :--- | :--- | :--- | | ≤10 | 0.02 | 0.05 | 0.1 | | >10 to 30 | 0.05 | 0.1 | 0.2 | | >30 to 100 | 0.1 | 0.2 | 0.4 | | >100 to 300 | 0.2 | 0.4 | 0.8 | | >300 to 1000 | 0.3 | 0.6 | 1.2 | | >1000 to 3000 | 0.4 | 0.8 | 1.6 |