| Range of Nominal Length (mm) | Grade H | Grade K | Grade L | | :--- | :--- | :--- | :--- | | up to 10 | 0.02 | 0.05 | 0.1 | | >10 up to 30 | 0.05 | 0.1 | 0.2 | | >30 up to 100 | 0.1 | 0.2 | 0.4 | | >100 up to 300 | 0.2 | 0.4 | 0.8 | | >300 up to 1000 | 0.3 | 0.6 | 1.2 | | >1000 up to 3000 | 0.4 | 0.8 | 1.6 |
The ISO 2768 General Tolerances PDF is more than just a document; it is the silent language of precision engineering. It tells your machinist exactly how much error is acceptable without forcing you to label every single line on your blueprint.
Remember the golden rule: Select the loosest possible tolerance that still allows the part to function. This saves time, money, and material. For 90% of standard machine shop work, ISO 2768-mK (Medium for size, Standard for geometry) is the perfect default. Iso 2768 General Tolerances Pdf
This table applies to external dimensions (e.g., shaft diameter), internal dimensions (e.g., hole diameter), and step dimensions.
| Range of Nominal Sizes (mm) | Tolerance Class f (Fine) | Tolerance Class m (Medium) | Tolerance Class c (Coarse) | Tolerance Class v (Very Coarse) | | :--- | :--- | :--- | :--- | :--- | | 0.5 up to 3 | ±0.05 | ±0.1 | ±0.2 | - | | >3 up to 6 | ±0.05 | ±0.1 | ±0.3 | ±0.5 | | >6 up to 30 | ±0.1 | ±0.2 | ±0.5 | ±1.0 | | >30 up to 120 | ±0.15 | ±0.3 | ±0.8 | ±1.5 | | >120 up to 400 | ±0.2 | ±0.5 | ±1.2 | ±2.5 | | >400 up to 1000 | ±0.3 | ±0.8 | ±2.0 | ±4.0 | | >1000 up to 2000 | ±0.5 | ±1.2 | ±3.0 | ±6.0 | | Range of Nominal Length (mm) | Grade
Note: Values are in millimeters (mm).
For symmetry (position), the tolerance is equal to the geometrical tolerance grade value. For run-out, the general tolerance is always 0.1mm (for Grade H, K, or L) as per ISO 2768-2. Based on your keyword "Iso 2768 General Tolerances
Based on your keyword "Iso 2768 General Tolerances Pdf", an enhanced feature could be:
"Generate a compliant ISO 2768 tolerance summary sheet (PDF)"
Angular tolerances apply to angles expressed in degrees, minutes, and seconds. The tolerance depends on the length of the shorter side of the angle.
| Length of Shorter Side | Class f / m | Class c / v | | :--- | :--- | :--- | | Up to 10 | ±1° | ±1°30' | | Over 10 up to 50 | ±0°30' | ±1° | | Over 50 up to 120 | ±0°20' | ±0°30' | | Over 120 up to 400 | ±0°10' | ±0°20' | | Over 400 | ±0°5' | ±0°10' |