This part of ISO 2768 is intended to simplify drawing indications and it specifies general tolerances for linear and angular dimensions without individual tolerance indications in four tolerance classes. NOTE 1: The concepts behind the general tolerancing of linear and angular dimensions are described in annex A. It applies to the dimensions of parts that are produced by metal removal or parts that are formed from sheet metal. NOTE 2: These tolerances may be suitable for use with materials other than metal. NOTE 3: Parallel International Standards exist or are planned, e.g. see ISO 8062 for castings. This part of ISO 2768 only applies for the following dimensions which do not have an individual tolerance indication: a) linear dimensions (e.g. external sizes, internal sizes, step sizes, diameters, radii, distances, external radii and chamfer heights for broken edges); b) angular dimensions, including angular dimensions usually not indicated, e.g. right angles (90°), unless reference to ISO 2768-2 is made, or angles of uniform polygons; c) linear and angular dimensions produced by machining assembled parts. It does not apply for the following dimensions: a) linear and angular dimensions which are covered by reference to other standards on general tolerances; b) auxiliary dimensions indicated in brackets; c) theoretically exact dimensions indicated in rectangular frames.