Never rely on general tolerances for press fits, sealing surfaces, or high-speed rotating components. Flag these with explicit tolerances.
ISO 2768-1 defines four classes of tolerances. As you move from "f" to "v," the tolerance becomes looser (more deviation allowed). Iso 2768 General Tolerances Pdf
Engineers and machinists frequently seek out a downloadable for several vital reasons: Never rely on general tolerances for press fits,
| Class | Description | Typical Application | | :--- | :--- | :--- | | | Fine | Precision engineering, small electronic components. | | m | Medium | General machinery, standard CNC parts. (Most common) | | c | Coarse | Fabricated parts, welded assemblies, castings. | | v | Very Coarse | Rough structural components, sheet metal work. | As you move from "f" to "v," the
It is important to note that ISO 2768 is currently under revision. The updated standard, , is expected to be published in 2025. It will bring the standard in line with the latest ISO GPS (Geometrical Product Specifications) framework. Designers and engineers should stay informed about these changes and prepare to transition to the new version once it is released.
ISO 2768 solves this problem by providing a blanket set of rules. A single note in the drawing title block—such as —applies a standard matrix of acceptable variations to all non-toleranced dimensions. Benefits to Manufacturing