ISO 2768 is the international standard used to simplify technical drawings by providing general tolerances
Specifying "ISO 2768-m" allows the machinist to use standard, efficient tools rather than specialized, slow, and expensive precision equipment.
Establishes a universal language between design firms and external manufacturing vendors worldwide. Industry Transition Note
Always consult your manufacturer before setting a class. Requesting an "fH" specification on an old manual lathe will drive up production costs exponentially or result in rejected manufacturing bids. iso 2768 general tolerances pdf exclusive
Permissible deviations in mm for nominal length ranges.
| Nominal Length Range of Shorter Side (mm) | Fine (f) | Medium (m) | |------------------------------------------:|:--------:|:----------:| | 0 – 10 | ±1° | ±1° | | 10 – 50 | ±0°30' | ±0°30' | | 50 – 120 | ±0°20' | ±0°20' | | 120 – 400 | ±0°10' | ±0°10' | | >400 | ±0°5' | ±0°5' |
In the world of precision manufacturing and mechanical engineering, clarity is the foundation of quality. When a design drawing lacks specific tolerances for every single dimension, ISO 2768 serves as the universal "safety net." This international standard simplifies drawings, reduces administrative overhead, and ensures that manufacturers and clients are on the same page regarding acceptable deviations. What is ISO 2768? ISO 2768 is the international standard used to
The permissible deviation depends on the length of the part and the selected class. Note the shift in upcoming 2025 standard:
| Nominal Length Range of the Shorter Side (mm) | f (Fine) | m (Medium) | | :--- | :--- | :--- | | up to 10 | ±1° | ±1° | | over 10 up to 50 | ±0° 30’ | ±0° 30’ | | over 50 up to 120 | ±0° 20’ | ±0° 20’ | | over 120 up to 400 | ±0° 10’ | ±0° 10’ | | over 400 | ±0° 5’ | ±0° 5’ |
Used for non-critical features like rough castings. ISO 2768 General Tolerance Guide | PDF - Scribd Requesting an "fH" specification on an old manual
The ISO 2768 general tolerances standard is significant in various industries, including:
Part 2 utilizes three tolerance classes, denoted by capital letters: – Fine K – Medium L – Coarse Straightness and Flatness
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.
Aligns production with standard workshop accuracies, preventing over-engineering.
For angular dimensions, the tolerance is applied to the of the angle. Range (mm) m (medium) c (coarse) v (very coarse) Up to 10 Over 10 up to 50 Over 50 up to 120 Over 120 up to 400 ISO 2768-2: Geometrical Tolerances