: The governing international standard for general engineering tolerances.
is a combined shorthand notation used on engineering drawings and technical documents. It references three parts of the ISO 2768 standard, which specifies default tolerances for linear dimensions, angular dimensions, geometrical features (form, orientation, location, and runout), and the indication of "E" for general external radius and chamfer dimensions. iso 2768-mk-e
Class is the medium class for geometric tolerances. It applies to features where no individual geometric tolerance is specified. Class is the medium class for geometric tolerances
When a designer writes ISO 2768-MK-E in the title block or general notes of a drawing, it instructs the manufacturer that must conform to the specific limits defined by this standard. 400 | ±0°5' |
is a powerful, time-saving default tolerance specification for general mechanical engineering. It balances cost and precision, eliminating the need to individually tolerance every dimension on a drawing. The "M" ensures reasonable linear and angular accuracy, "K" provides essential geometric controls, and "E" extends the logic to common external rounded edges and chamfers.
| Nominal Length of Shorter Side (mm) | Tolerance (± degrees/minutes) | |--------------------------------------|-------------------------------| | Up to 10 | ±1° | | >10 to 50 | ±0°30' | | >50 to 120 | ±0°20' | | >120 to 400 | ±0°10' | | >400 | ±0°5' |