| Standard | Focus | Relationship to ISO 286 | | :--- | :--- | :--- | | | Limits & Fits for linear sizes | The core standard | | ISO 2768 | General tolerances (no individual inspection) | Complementary (less precise) | | ISO 14405 | Linear size tolerancing (alternative to ±) | Overlapping, newer philosophy | | ANSI/ASME B4.2 | Inch-based limits & fits (US) | Similar logic, different units |
Refers to all external features of a workpiece (e.g., a pin, a key). It is always designated by lowercase letters (e.g., 3. Deviations and Tolerance
Determine whether your mechanism needs to rotate (clearance), remain locked (interference), or locate precisely (transition).
When someone says they need an "ISO 286 PDF," they are almost always referring to the tables in .
The ISO 286 system allows for two approaches to designing fits: iso 286 pdf
50 H 7 / g 6 | | | | | Nominal | IT Grade | IT Grade Size | for Hole | for Shaft | | Hole Position Shaft Position Use code with caution. The Letter: Tolerance Zone Position
This is the foundational document. Think of it as the textbook. establishes the theory, formulas, and calculations behind the entire system. It does not typically contain comprehensive tables of pre-calculated values. Instead, it provides the mathematical basis and the methodology for calculating standard tolerances (IT values) and fundamental deviations for any given nominal size.
Instead of manually calculating limits using complex mathematical formulas, the PDF contains exhaustive lookup tables organized by nominal size steps (e.g., 0–3mm, 3–6mm, 6–10mm, up to 3150mm).
Using the ISO 286-2 tables, you can determine the exact upper and lower limits: | Standard | Focus | Relationship to ISO
The limits are -9 µm / -25 µm (Actual size must be between 49.975 mm and 49.991 mm). Hole-Basis vs. Shaft-Basis Systems
ISO 286 establishes the "ISO code system for tolerances on linear sizes." It replaced older regional systems to create a unified global framework for engineering tolerances. By defining standard limits and fits, it eliminates ambiguity between design engineers and machine shops. The standard is divided into two primary parts:
ISO 286 (officially titled Geometrical product specifications (GPS) – ISO code system for tolerances on linear sizes ) is the international standard that defines the system of limits and fits for cylindrical workpieces. In simple terms, it tells engineers how much a manufactured part can deviate from its exact design size while still functioning perfectly.
for the shaft) to find the upper and lower limits in micrometers ( When someone says they need an "ISO 286
A shaft with a nominal diameter of 50 mm, a "g" fundamental deviation (slightly smaller than 50 mm), and an IT6 tolerance grade width. 4. Types of Fits in ISO 286
What are the for your hole or shaft (e.g., H7, g6)?
For those seeking the official , the standard is available for purchase from ISO national member bodies and authorized distributors. While free resources exist for reference, the complete, authoritative standard requires purchase. Understanding ISO 286 is essential for anyone involved in mechanical design, manufacturing, or quality control, enabling global collaboration and ensuring that parts fit together as intended, every time.