Auxiliary device for determining machining axis of large crank shaft of dragline excavator

An auxiliary device for determining the machining axis of a large crank shaft of a dragline excavator relates to the technical field of crank shaft determination machining and comprises a first fixing plate arranged at the front end of a workpiece and a tail fixing device arranged at the rear end of the workpiece, the first fixing plate is connected with the front end of the workpiece through a bolt and abuts against a tailstock of a lathe, and the tail fixing device is arranged at the rear end of the workpiece. The tail fixing device is connected with the rear end of the workpiece through a bolt, and the tail fixing device is fixedly installed on a chuck of a lathe spindle box. The first fixing plate and the second fixing plate are provided with the penetrating holes corresponding to the axes of workpiece machining, and the penetrating holes are used for assisting machining of the axes of the crank shaft. The tail fixing device is arranged at the rear end of the workpiece, so that the tightness degree of the