MIL-HDBK-404, MILITARY HANDBOOK CALCULATION AND DESIGN OF MASTER GEARS (12 JUN 1990). This handbook includes the instructions for the design, development, and calculation and for specifying requirements of master gears for the functional inspection of external and internal, spur and helical, parallel and askew axis, involute profile gears. Materials pertinent to the inspection of bevel and worm gears and related inspection equipment are also covered.