Dimensioning and Tolerancing (ASME Y 14.5)

The Y14.5 standard is considered the authoritative guideline for the design language of geometric dimensioning and tolerancing (GD&T.) It establishes uniform practices for stating and interpreting GD&T and related requirements for use on engineering drawings and in related documents.

GD&T is an essential tool for communicating design intent — that parts from technical drawings have the desired form, fit, function and interchangeability. By providing uniformity in drawing specifications and interpretation, GD&T reduces guesswork throughout the manufacturing process — improving quality, lowering costs, and shortening deliveries.

Now, a consensus committee of experts has revised Y14.5 for 21st-century applications. Important changes address: concept of feature of size; datum references and degrees of freedom; composite position tolerances; surface boundaries and axis methods of interpretation; profile tolerances; and symbology and modifiers tools. Additionally, the subject matter has been restructured for better readability, with profile, orientation, and form now in separate sections, and material within sections reorganized.

ASME Y14.5-2009 is a replacement of ASME Y14.5M-1994.

Foreword
Committee Roster
Correspondence with the Y14 Committee

Section 1 : Scope, Definitions, and General Dimensioning
Section 2 : General Tolerancing and Related Principles
Section 3 : Symbology
Section 4 : Datum Reference Frames
Section 5 : Tolerances of Form
Section 6 : Tolerances of Orientation
Section 7 : Tolerances of Location
Section 8 : Tolerances of Profile
Section 9 : Tolerances of Runout

Nonmandatory Appendices
A : Principal Changes and Improvements
B : Formulas for Positional Tolerancing
C : Form, Proportion, and Comparison of Symbols
D : Former Practices
E : Decision Diagrams for Geometric Control
Index