Without ISO 286, global manufacturing would be a mess. By following this code system, a shaft manufactured in Tokyo will fit perfectly into a hole machined in Berlin.
The official ISO website allows you to purchase and download genuine PDF copies of ISO 286-1 and ISO 286-2.
: Parts from different suppliers can be swapped without custom adjustments. iso 286 pdf
ISO 286 is a foundational Geometrical Product Specification (GPS) standard that establishes an international code system for tolerances on linear sizes, covering hole and shaft systems, as detailed in ISO 286-1 and ISO 286-2 . It defines fundamental deviations, fits, and Standard Tolerance Grades (IT) to ensure interchangeability, with specifications applicable at a reference temperature of 20°C. For the full technical documents, consult Sharif CAD/CAM and Almaseh Sanj.
Manufacturers do not need to over-engineer tolerances; they can select the most cost-effective fit that satisfies the functional requirement. Without ISO 286, global manufacturing would be a mess
– Explains the fundamental concepts, terminology, and graphical representations of limits and fits.
These determine the position of the tolerance zone relative to the nominal size. Used for Holes . Lowercase Letters (a–zc): Used for Shafts . ISO 286 Fit System: Clearance, Transition, and Interference : Parts from different suppliers can be swapped
In engineering drawings, a tolerance is written as a combination of the nominal size, the fundamental deviation letter, and the IT grade number. : The nominal size in millimeters (
ISO 286 is an international standard established by the International Organization for Standardization (ISO). It defines the universally accepted system of tolerances, deviations, and fits for linear sizes of features like cylinders (holes and shafts) and parallel surfaces.
The letter "H" (for holes) and "h" (for shafts) aligns the lower limit of the tolerance zone exactly with the nominal zero line.
Higher numbers represent wider tolerances (lower precision, less expensive to manufacture).