The standard categorizes workpieces into three main classes:
This table provides permissible deviations in millimeters for external sizes (shafts), internal sizes (holes), and features like step heights or radii. For a nominal size range (e.g., 0.5 mm up to 3000 mm), the table lists the upper and lower deviation limits for each class. For example, a 100 mm linear dimension under the “medium” class might show a tolerance of ±0.3 mm, while the “fine” class would show a tighter ±0.1 mm. iso 20457 tolerance table pdf
When reviewing a , ensure you are referencing the correct: The standard categorizes workpieces into three main classes: