The callout is the most common general tolerance designation used globally, particularly for CNC machining and sheet metal fabrication. It combines two distinct parts of the standard to cover both physical size and geometric form. 1. What does "mk" stand for?
Below is a snapshot of the allowable deviations for linear dimensions under the "m" (medium) class: Dimension Range (mm) Tolerance (± mm) 120 to 400 400 to 1000 Best Practices for Implementation general tolerance iso 2768-mk
If you need a precision shaft to slide into a hole, you must use a standard like ISO 286 (e.g., H7/g6) instead of general tolerances. The callout is the most common general tolerance