Clamp special for butterfly valve

The utility model relates to the technical field of work fixtures, can stably clamp a butterfly valve and ensure the machining precision in the processes of machining a main valve rod hole and an auxiliary valve rod hole and turning the end face of an upper flange, and has the technical characteristics of simple structure and convenience in use. The special clamp for the butterfly valve comprises a fixing disc, a workbench and a pressing assembly. The fixed disc is fixed on a main shaft flange of a lathe; the left end of the workbench is fixed to the right end face of the fixing disc and is perpendicular to the right end face of the fixing disc, and the right end face of the workbench is parallel to the right end face of the fixing disc and used for positioning the bottom face of an upper flange of a to-be-machined valve body. A round boss is arranged on the top face of the workbench, the outer diameter of the boss is matched with the inner diameter of a valve cavity of a valve body to be machined or the inne