scope:

GENERAL

This Standard establishes uniform practices for stating and interpreting dimensioning, tolerancing, and related requirements for use on engineering drawings and in related documents. For a mathematical explanation of many of the principles in this Standard, see ASME Y14.5.1M. Practices unique to architectural and civil engineering and welding symbology are not included.

Section 1, General. This Section establishes definitions, fundamental rules, and practices for general dimensioning that apply to coordinate as well as geometric dimensioning methods. For tolerancing practices, see Sections 2 through 6.

Units. The International System of Units (SI) is featured in this Standard because SI units are expected to supersede United States (U.S.) customary units specified on engineering drawings. Customary units could equally well have been used without prejudice to the principles established.

Reference to this Standard. Where drawings are based on this Standard, this fact shall be noted on the drawings or in a document referenced on the drawings. References to this Standard shall state ASME Y14.5M-1994.

Figures. The figures in this Standard are intended only as illustrations to aid the user in understanding the principles and methods of dimensioning and tolerancing described in the text. The absence of a figure illustrating the desired application is neither reason to assume inapplicability, nor basis for drawing rejection. In some instances, figures show added detail for emphasis. In other instances, figures are incomplete by intent. Numerical values of dimensions and tolerances are illustrative only.

NOTE: To assist the users of this Standard, a listing of the paragraph(s) that refer to an illustration appears in the lower right-hand corner of each figure. This listing may not be all-inclusive. The absence of a listing is not a reason to assume inapplicability.

Notes. Notes herein in capital letters are intended to appear on finished drawings. Notes in lower case letters are explanatory only and are not intended to appear on drawings.

Reference to Gaging. This document is not intended as a gaging standard. Any reference to gaging is included for explanatory purposes only.

Symbols. Adoption of the symbols indicating dimensional requirements, as shown in Fig. C-2 of Appendix C, does not preclude the use of equivalent terms or abbreviations where symbology is considered inappropriate.