Companion Flanges, Type A (External Pilot) and Type S (Internal Pilot)
This SAE Standard specifies the nominal dimensions and tolerances which affect the interchangeability between companion flanges and mating parts. The flanges covered by this document are designated type A and type S. The type A flanges are equivalent to type A ISO 7646. The type S flanges are equivalent to the type S ISO 7647. Type A is an external (male) pilot construction and type S is an internal (female) pilot construction. These flanges are not interchangeable. Dimensions not specified are left to the discretion of the component manufacturer.