Thread Gages also referred to as Thread Gauges are used to check the outside major diameter and pitch diameter limits on threaded parts. They are also used to check the inside major diameter and pitch diameter limits on threaded parts. Thread gages are available in GO and NOGO. The GO thread gage should go on or in a threaded component and the NOGO should not. They are used to inspect pitch diameter and the functional thread. Thread gages determine if the product threads pass or fail inspection.