If you are looking for information on ISO 2768 General Tolerances
, here is a breakdown of the standard used to simplify technical drawings by providing universal tolerance classes for dimensions without individual indications. 🛠️ What is ISO 2768?
ISO 2768 is an international standard that defines general tolerance classes for linear and angular dimensions, as well as geometrical features. It is divided into two primary parts: ISO - International Organization for Standardization Part 1 (ISO 2768-1):
Focuses on linear and angular dimensions. It specifies four tolerance classes: (very coarse) Part 2 (ISO 2768-2):
Focuses on geometrical tolerances (GD&T) such as flatness, straightness, and symmetry. It uses three classes: 📄 Why Use General Tolerances? Simplification: Iso 2768 General Tolerances Pdf
Reduces the number of specific tolerance callouts on a drawing, making it cleaner and easier to read. Efficiency:
Speeds up the design and manufacturing workflow by providing a "default" accuracy level. Cost-Effective:
Prevents over-engineering by applying appropriate tolerances based on the manufacturing process. 🔍 Resources & Downloads
While the official full-text standard is a paid document, many manufacturers and engineering hubs provide summary tables and PDF guides for reference: Official Standard: You can purchase the current version directly from the ISO 2768-1 Official Page Technical Guides: Sites like If you are looking for information on ISO
offer detailed breakdowns and charts of the tolerance values for each class. Quick Reference PDF:
For a visual summary of the tolerance tables, you can view this General Tolerance Guide ZEISS Quality Forum specific numerical values
The ISO 2768 standard is a foundational document in mechanical engineering, providing a global language for general tolerances
on technical drawings. By referencing this standard, engineers can avoid the tedious and cluttering task of specifying individual tolerances for every single dimension, relying instead on a set of "default" accuracy levels. Why ISO 2768 is Essential Cost Reduction: Loose general tolerances mean less scrap,
In modern manufacturing, every feature on a part has a theoretical size and shape, but real-world processes like CNC machining or sheet metal forming always involve slight deviations. ISO 2768 ensures that: Standard Tolerances in Manufacturing: ISO 2768 & ISO 286
The core concept behind ISO 2768 is "functionality." The standard assumes that dimensions with no specific tolerance are not critical to the assembly or function of the part. Therefore, the tolerances provided in the standard represent the normal manufacturing accuracy of common machining processes.
By using these general tolerances, manufacturers can avoid unnecessary costs. If a shop can meet the general tolerance class using standard equipment, they do not need to slow down production to achieve unnecessary precision on non-critical features.
Angular tolerances are given for the shorter side of the angle (in millimeters per meter or degrees/minutes).
| Range of Nominal Length of Shorter Side (mm) | Fine (f) | Medium (m) | Coarse (c) | Very Coarse (v) | | :--- | :--- | :--- | :--- | :--- | | up to 10 | ±1° | ±1° | ±1°30' | ±3° | | >10 up to 50 | ±0°30' | ±0°30' | ±1° | ±2° | | >50 up to 120 | ±0°20' | ±0°20' | ±0°30' | ±1° | | >120 up to 400 | ±0°10' | ±0°10' | ±0°15' | ±0°30' | | >400 | ±0°5' | ±0°5' | ±0°10' | ±0°20' |