ISO 17485:2006 provides the gear manufacturer and the gear buyer with a mutually advantageous reference for uniform tolerances. Ten accuracy grades are defined, numbered 2 to 11 in order of decreasing precision.
ISO 17485:2006 does not apply to enclosed gear unit assemblies, including speed reducers or increasers, gear motors, shaft mounted reducers, high speed units, or other enclosed gear units manufactured for a given power, speed, ratio or application.
Gear design is beyond the scope of ISO 17485:2006. The use of the accuracy grades for the determination of gear performance requires extensive experience with specific applications. Therefore, the users of this International Standard are cautioned against the direct application of tolerance values to a projected performance of unassembled (loose) gears when they are assembled.