This standard is intended to simplify drawing indications and it specifies general tolerances for linear and angular dimensions without individual tolerance indications in four tolerance classes1). It applies to the dimensions of parts that are produced by metal removal or parts that are formed from sheet metal. These tolerances may be suitable for use with materials other than metal. This part only applies to 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 (90o), or angles of uniform polygons. c) Linear and angular dimensions produced by machining assembled parts. It does not apply to 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.