Iso 2768-mh Tolerance Chart -
Linear tolerances (m), nominal size L (mm) → tolerance ±:
When you see on a technical drawing, it means that unless otherwise specified, the workshop must adhere to the Medium linear tolerances and High (h) geometric tolerances listed above. This approach reduces drafting time and clarifies which dimensions are critical versus standard.
Class (Medium) is the most common tolerance class for CNC machined metal parts. Below are the permissible deviations for linear measures and angles. Nominal Size Range (mm) Linear Dimensions (mm) Ext. Radii & Chamfers (mm) Angular Dimensions ±plus or minus ±plus or minus ±plus or minus ∘raised to the composed with power (up to 10mm) ±plus or minus ±plus or minus ±plus or minus ∘raised to the composed with power 30' (10-50mm) ±plus or minus ±plus or minus ±plus or minus ∘raised to the composed with power 20' (50-120mm) > 30 to 120 ±plus or minus ±plus or minus ±plus or minus ∘raised to the composed with power 10' (120-400mm) > 120 to 400 ±plus or minus ±plus or minus ±plus or minus ∘raised to the composed with power 5' (over 400mm) > 400 to 1000 ±plus or minus Sources: Part 2: Geometrical Tolerances (Class "H")
Exceeding these tolerances does not automatically mean a part is rejected; it only leads to rejection if the part's function is impaired. iso 2768-mh tolerance chart
In the world of engineering and manufacturing, tolerances play a crucial role in ensuring that parts and components fit together seamlessly. One of the most widely used tolerance standards is the ISO 2768-MH tolerance chart, which provides a set of guidelines for determining the acceptable limits of variation in the dimensions of parts and components. In this article, we will take a closer look at the ISO 2768-MH tolerance chart, its significance, and how to use it effectively.
This defines the tolerances for linear and angular dimensions (length, radii, diameters). The "m" stands for Medium .
The longer of the two features defines the reference element . Linear tolerances (m), nominal size L (mm) →
Appendix: Always consult the official ISO 2768‑1 and ISO 2768‑2 documents (and any national adoptions) for authoritative tables and exact wording before applying tolerances contractually.
What are you planning to use? (CNC milling, sheet metal, injection molding?) What is the primary function or material of the component?
The Ultimate Guide to the ISO 2768-mh Tolerance Chart In mechanical engineering and manufacturing, specifying precise dimensions for every single feature on a technical drawing is highly inefficient. To streamline this process, the International Organization for Standardization established . Below are the permissible deviations for linear measures
To implement this, simply add a note in or near the title block of your technical drawing: When NOT to Use It
The designation is split into two distinct parts that cover different aspects of a part's geometry: m (Medium): ISO 2768-1 , which defines general tolerances for linear and angular dimensions . It is the most common class for standard machining. ISO 2768-2 , which covers geometrical tolerances like straightness, flatness, and perpendicularity. The Linear Tolerance Chart (m) For a drawing labeled ISO 2768-m
Combined, provides a comprehensive baseline for a component made via CNC machining, sheet metal fabrication, or conventional milling [5]. Part 1: ISO 2768-1 (m) – Linear and Angular Dimensions
While primarily for material removal (like CNC machining), it can be applied to other processes with special examination. ISO 2768-2