Special gauge for countersunk threaded hole of air disc brake

The invention provides a special gauge for a countersunk threaded hole of an air pressure disc brake, and belongs to the technical field of machining detection. According to the technical scheme, the special gauge for the countersunk threaded hole of the air pressure disc brake comprises a cylindrical threaded go/no-go gauge, the bottom of the threaded go/no-go gauge is a threaded part, the threaded go/no-go gauge is matched with the threaded part of the countersunk threaded hole to be detected, the middle of the threaded go/no-go gauge is of a smooth cylinder structure, and the top of the threaded go/no-go gauge is a holding part; the reference seat is a cantilever of a radial cross structure, a through hole is formed in the middle of the reference seat and penetrates through a middle smooth cylinder structure of the thread go-no go gauge, guide groove cavities are formed in the four parts of the cantilever of the reference seat respectively, and radius scales are arranged on the side faces of the cantilever