This part uses four tolerance classes, represented by lowercase letters, ranging from highest to lowest precision: What is ISO 2768 Standard in Machining - 3ERP
| Length of Feature (mm) | Class H | Class K | Class L | | :--- | :--- | :--- | :--- | | | 0.5 | 0.6 | 0.6 | | Over 100 up to 300 | 0.5 | 0.6 | 1.0 | | Over 300 up to 1000 | 0.5 | 0.8 | 1.5 | | Over 1000 up to 3000 | 0.5 | 1.0 | 2.0 | iso 2768 pdf
Linguistically, the phrase “ISO 2768 PDF” is revealing. It is not a search for “purchase ISO 2768” or “ISO 2768 summary.” The explicit filetype specification—PDF—indicates a desire for possession, not just knowledge. The seeker wants a portable, offline, printable, and often permanent artifact. This reflects a psychological need for tangible authority in a digital world. A cloud-based interactive tolerance table does not satisfy; only the static, paginated, official-looking PDF confers the legitimacy needed to defend a manufacturing decision in a quality audit. This part uses four tolerance classes, represented by
ISO 2768-2 applies only when the drawing references this specific part of the standard (e.g., "ISO 2768-mK"). If only ISO 2768-m is referenced, Part 2 does not apply. This reflects a psychological need for tangible authority
| Nominal Dimension Range (mm) | Class f (fine) | Class m (medium) | Class c (coarse) | Class v (very coarse) | | :--- | :--- | :--- | :--- | :--- | | | $\pm 0.05$ | $\pm 0.1$ | $\pm 0.2$ | — | | Over 3 up to 6 | $\pm 0.05$ | $\pm 0.1$ | $\pm 0.3$ | $\pm 0.5$ | | Over 6 up to 30 | $\pm 0.1$ | $\pm 0.2$ | $\pm 0.5$ | $\pm 1.0$ | | Over 30 up to 120 | $\pm 0.15$ | $\pm 0.3$ | $\pm 0.8$ | $\pm 1.5$ | | Over 120 up to 400 | $\pm 0.2$ | $\pm 0.5$ | $\pm 1.2$ | $\pm 2.5$ | | Over 400 up to 1000 | $\pm 0.3$ | $\pm 0.8$ | $\pm 2.0$ | $\pm 4.0$ | | Over 1000 up to 2000 | $\pm 0.5$ | $\pm 1.2$ | $\pm 3.0$ | $\pm 6.0$ | | Over 2000 up to 4000 | — | $\pm 2.0$ | $\pm 4.0$ | $\pm 8.0$ |