ISO 678:1976

Straight bevel gears for general engineering and heavy engineering — Modules and diametral pitches

Specifies and defines modules and diametral pitches. ISO 678 is intended essentially to facilitate the establishment of series of cutting tools, and cannot prevent the use of unstandardized modules or diametral pitches, for instance by using the tool for the module or diametral pitch corresponding to the next smaller size given in the table.