Abstract: An apparatus for use in supporting a disc brake rotor upon a brake lathe includes a support arbor having a generally cylindrical flange and an extending elongated cylindrical arbor shaft defining a left hand thread at its end portion. A disc brake rotor is received upon the arbor shaft and supported thereby. A generally cylindrical spacer defining a center bore is received upon the arbor shaft and is secured thereto by a threaded fastener. The assembly of the support arbor, disc brake rotor, spacer and threaded fastener are further supported upon the arbor of a conventional brake lathe. The apparatus facilitates the machining of disc brake rotor surfaces for rotors which include a bearing structure which otherwise prevents support upon a conventional brake lathe.