ISO 2768‑1 applies to linear and angular dimensions on drawings for products manufactured by conventional methods (machining, forming, casting, forging) when tighter tolerances are not specified. ISO 2768‑2 addresses geometrical tolerances (flatness, perpendicularity, etc.) and complements the first part. Use ISO 2768 when:
| Feature | Tolerance Class | Key Values | | :--- | :--- | :--- | | Linear dimensions (0.5–4000mm) | m | ±0.1mm up to 6mm, ±0.2mm up to 30mm, ±0.3mm up to 120mm, ±0.5mm up to 400mm | | Radii and chamfers (0.5–6mm+) | m | ±0.2mm up to 3mm, ±0.5mm up to 6mm, ±1.0mm over 6mm | | Angular dimensions (0–400+ mm) | m | ±1° up to 10mm, ±0°30′ up to 50mm, ±0°20′ up to 120mm | | Straightness/Flatness | H | 0.02mm up to 10mm, 0.05mm up to 30mm, 0.1mm up to 100mm | | Perpendicularity | H | 0.2mm up to 100mm, 0.4mm up to 300mm | | Symmetry | H | 0.5mm for up to 3000mm | | Circular run-out | H | 0.1mm | iso 2768-mh tolerance chart
(Note: Class H preserves a flat 0.5 mm limit for symmetry across all lengths up to 3000 mm). Circular Run-Out ISO 2768‑1 applies to linear and angular dimensions
This table defines the permitted deviation for angles, based on the length of the shorter side. The tolerances for the medium (m) class are identical to the fine (f) class. Circular Run-Out This table defines the permitted deviation
represents "medium" accuracy, which is the industry standard for most CNC machining and general workshop practices. Table 1: Linear Dimensions (Permissible deviations in mm) Nominal Length (mm) m (medium) c (coarse) v (very coarse) Over 3 to 6 Over 6 to 30 Over 30 to 120 Over 120 to 400 Over 400 to 1000 Over 1000 to 2000 Over 2000 to 4000 Academia.edu Table 2: External Radii and Chamfer Heights (mm) Nominal Size f (fine) / m (medium) c (coarse) / v (very coarse) Over 3 to 6 Part 2: Geometrical Tolerances (Class "H") The "H" in
Ultimate Guide to the ISO 2768-MH Tolerance Chart ISO 2768-MH is an international manufacturing standard that simplifies engineering drawings by defining standard tolerances for linear and angular dimensions. Instead of labeling every single dimension with an individual tolerance, designers use this standard to establish a baseline of acceptable variation.
ISO standards are universally recognized. A drawing designed under ISO 2768-mh in Europe can be perfectly understood and manufactured by a machine shop in Asia or North America without communication friction. Practical Application Rules