Standards for accuracy of gear tooth geometry have been developed by a number of governing bodies around the world and also in some cases by individual companies.
• The goal of these standards is to ensure that the manufacture of the gears meets the tolerances set by the designer for the intended application.
• These standards classify gears by quality numbers based on the as manufactured dimensions. Higher quality requires tighter, closer tolerances.
• The dimensions determine the level of quality. Determination of quality is performed with specialized, precision instrumentation and then compared to the standards.