Abstract : This report describes the results of an analytical study of the point efficiencies of various types of fuze gear trains. Involute and clock-tooth profiles for two and three pass step-up gear meshes which operate in spin and nonspin environments are compared, and the differences explored. The conclusions of an investigation concerning the geometrical factors which influence the point efficiencies of multipass step-up gear trains are discussed. The analyses on which these results are based are given in detail.