Casting polishing device for machining

The invention relates to the technical field of polishing, in particular to a casting polishing device for machining, comprising a fixing mechanism for fixing a casting; and the polishing mechanism is used for polishing the inner wall of the casting and fixedly installed at the bottom of the inner wall of the fixing mechanism, and the fixing mechanism is arranged, so that during fixing, the pneumatic push rod drives the annular partition plate to slide upwards along the inner wall of the oil storage barrel; at the moment, the top ends of the two arc-shaped rods drive the elastic clamping blocks on the two sides to get close to each other correspondingly, and therefore the fixing process of the barrel-shaped castings with the different diameters can be completed; and the grinding pieces fixedly connected with the surfaces of the sliding strips and the grinding pieces fixedly connected with the surfaces of the fixing sleeves are staggered, so that the contact area between the friction pieces and the barrel bott