ASME Y14.5 is a standard published by the American Society of Mechanical Engineers (ASME) to establish rules, symbols, definitions, requirements, defaults, and recommended practices for stating and interpreting Geometric Dimensions and Tolerances (GD&T).[1] ASME/ANSI issued the first version of this Y-series standard in 1973.[2]
ASME Y14.5 is a complete definition of Geometric Dimensioning and Tolerancing. It contains 15 sections which cover symbols and datums as well as tolerances of form, orientation, position, profile and runout.[3] It is complemented by ASME Y14.5.1 - Mathematical Definition of Dimensioning and Tolerancing Principles. Together these standards allow for clear and concise detailing of dimensional requirements on a product drawing or electronic drawing package as well as the verification of the requirements on manufactured parts. Effective application of GD&T allows for parts to be verified by dimensional measurements, gauging, or by CMM.
The modern standard can trace its roots to the military standard MIL-STD-8 published in 1949.[4] It was revised by MIL-STD-8A in 1953, which introduced the concept of modern GD&T "Rule 1".[5][6] Further revisions have continued to add new concepts and address new technology like Computer Aided Design and Model-based definition. A list of revisions follows:[6]