GMNA E-91 PDF

This standard establishes the method to designate controls for surface texture of solid materials. It includes methods for controlling roughness, waviness, and lay, and provides a set of symbols for use on drawings, specifications, or other documents. This standard does not provide definitions or specify the means by which the surface texture is to be producted or measured.  This standard basically duplicates the contents of American National Standard (ANSI) Y14.36-1987, Surface Texture Symbols. Additional surface texture control requirements are provided in the surface texture section in Section W of the GM Engineering Standards.