scope:

This International Standard specifies the characteristics of thestandard basic rack tooth profile for cylindrical involute gears(external or internal) for general and heavy engineering. ThisInternational Standard applies to the standardized modulesspecified in ISO 54. The defined profile does not take into accountthe possible cut-off of the height of internal teeth. This heightis to be calculated for each case. The standard basic rack toothprofile defined in this International Standard constitutes ageometrical reference for a system of involute gears in order tofix the sizes of their teeth. It does not constitute a definitionof a cutter, but a cutter may be defined from this standard basicrack tooth profile in order to realize a conforming profile.