Overview
EN ISO 286-1:2010 - "Geometrical product specifications (GPS) - ISO code system for tolerances on linear sizes - Part 1" defines the basis of tolerances, deviations and fits for linear sizes. It establishes the internationally accepted ISO code system for tolerances applicable to features of size of type cylinder and two parallel opposite surfaces (e.g., holes, shafts, slot widths, key thicknesses). The standard sets out core terminology, basic concepts, and a standardized selection of tolerance classes used for design and manufacturing to assure functional fits and interchangeability.
Key topics
- Scope and feature types: applies to cylinders and two parallel opposite surfaces; nominal sizes of mating features must be identical for fit application.
- Terminology and definitions: formal definitions for terms such as feature of size, nominal size, limit deviations, basic hole, and basic shaft.
- ISO code system and designation rules: how tolerance classes are designated and written (see Part 2 for tables).
- Principles of fits: basic terminology and rules to determine fits (clearance, transition, interference) between mating parts.
- Selection of tolerance classes: standardized guidance for choosing tolerance grades for general-purpose applications.
- Relationship to GPS matrix and dimensional tolerancing: positions ISO 286-1 within the GPS framework and notes interaction with ISO 14405-1 (dimensional tolerancing).
- Important updates: references the transition of default size association from the envelope criterion to the two-point size criterion per ISO 14405-1 and notes when additional form or surface texture controls may be needed.
Applications
EN ISO 286-1:2010 is used to:
- Specify tolerance systems on engineering drawings for shafts, holes, pins, keys, and slots.
- Ensure interchangeability and predictable fits in mass production.
- Guide designers and tolerancing engineers in selecting appropriate tolerance classes for manufacturability and function.
- Support quality engineers and inspection teams by providing the basis for limit deviations and acceptance criteria.
Typical users include mechanical designers, manufacturing engineers, metrology specialists, drawing and CAD standards authors, and suppliers producing mating components.
Related standards
- ISO 286-2 - Part 2: tables of standard tolerance grades and limit deviations for holes and shafts (essential companion for numeric values).
- ISO 14405-1 - Dimensional tolerancing (linear sizes) - clarifies size-association criteria (two-point vs envelope).
- ISO/TR and GPS matrix documents referenced for broader geometrical product specification context.
Keywords: EN ISO 286-1:2010, ISO code system for tolerances, tolerances on linear sizes, basic hole, basic shaft, fits, GPS, limit deviations, nominal size.
