UNE 1-121 Pt.1-1991 Technical illustration. Geometric tolerance. Overview, definitions, symbols and explanations of tolerance diagrams for shape, orientation, position and relief
1.1 The purpose of this standard is to establish the principles of symbolization and the indication of shape, orientation, position and oscillation tolerances in technical drawings, as well as the appropriate geometric definitions. Hereinafter, in this document, the term "geometric tolerances" will be used synonymously with this set of tolerances. 1.2 Geometric tolerances should be specified only where they are essential, that is, in the case of functional requirements, interchangeability and possible manufacturing issues. 1.3 The indication of geometric tolerances does not necessarily imply the use of a particular production, measurement or verification method.