The equations and values presented provide a general approach to design. Deviations from the methods and values stated in this design manual may be made when justified by experience, testing, or more specific analysis. It is intended for use by experienced gear designers capable of selecting reasonable values based on their knowledge of the performance of similar designs and the effect of such items as lubrication, deflection, manufacturing tolerances, metallurgy, residual stresses, and system dynamics. It is not intended for use by the engineering public at large. Because of the wide variety of applications of wormgearing, this design manual is a practical overview of wormgearing design and is intended as a guideline for users and manufacturers in the general principles of operation, the basic design concepts and formulas, the common thread forms used, the use of modified designs, tooling and manufacturing considerations, and the proper mounting, assembly and run--in of wormgearing.