Part I provides design data and other details of involute serrations of 45° pressure angle 10/20, 16/32 and 24/48 pitches for the full range 60 to 100 serrations, and 32/64, 40/80, 48/96, 64/128, 80/160 and 128/256 pitches for limited range. Limiting dimensions are tabulated and manufacturing errors and their effect on fit between mating serrated elements are discussed. Part II gives the methods of gauging and inspection, and the design details for gauges.