If you are a supplier or manufacturer working with parts specified under MS81-2021, ensure you have the correct revision of the PDF. Differences between "Revision 1" and "Revision 2" can lead to significant manufacturing errors, especially when transitioning from old "Class 1/2" systems to the current "f/m/c" classes.
While MS81-2021 is a corporate-specific standard, it is heavily based on international standards such as ISO 2768 , which also defines general tolerances for linear and angular dimensions. Ms81-2021 Standard Pdf
In modern Geometrical Product Specifications (GPS), newer standards like ISO 22081:2021 are beginning to replace older general tolerance methods by providing rules for general geometrical and size specifications to minimize individual indications on documentation. How to Reference MS81-2021 on Drawings If you are a supplier or manufacturer working
: On older technical drawings, you may see references to "1st Class" or "2nd Class" tolerances. Under modern enforcement, these older designations are often mapped to the Annex MS81-2021 requirements. Key Technical Specifications Key Technical Specifications : This standard applies to
: This standard applies to machining dimensions of less than 2000 mm for individual machining work.
When engineers create technical drawings, they don't always specify a tolerance for every single dimension to avoid clutter. Instead, they refer to a "General Tolerance" standard. The MS81-2021 (Revision 2) serves as the primary annex for general tolerances in machine-cut operations within specific corporate standards like MSF1-2021.
Summary for Manufacturers