Coordinate measurement of spiral and straight bevel gears improves design capability and enables interchangeable manufacture by precise definition of geometry and accurate measurement rather than by fitting to an existing mating part or “master” gear. The teeth are measured relative to perfectly conjugate teeth rather than to the modified shapes produced by an errorless machine. Application of coordinate measurements is an integral part of the bevel gear manufacturing process at Caterpillar Inc. The method of application differs from that developed by others in that the software was written independently, and the tooth shape plots are produced in a fashion much like those for an involute spur gear. The coordinate measurement check supersedes the subjective bearing contact pattern roll check for control of geometry, but the roll check is maintained as a supplementary routine inspection.
