This International Standard establishes a classification system that can be used to communicate geometrical
accuracy specifications of unassembled bevel gears, hypoid gears and gear pairs. It defines gear tooth accura-
cy terms, specifies the structure of the gear accuracy grade system, and provides allowable values. The stan-
dard provides the gear manufacturer and the gear buyer with a mutually advantageous reference for uniform
tolerances. Ten grades are defined, numbered 2 to 11 in order of decreasing precision. Equations for tolerances
and their ranges of validity are provided for bevel and hypoid gearing.