Combined boring cutter

The combined type boring cutter comprises a blade and a connecting block, the blade is connected with the connecting block through a screw, the connecting block is installed on an installation base, the installation base is connected with a base, the base is connected with a rotating shaft, an adjusting mechanism is arranged on the installation base, and an adjusting rod on the adjusting mechanism is connected with the connecting block; according to the device, an adjusting mechanism is arranged on a mounting seat, and in the process that a second pipeline inputs gas, a piston in an adjusting cavity is pushed, so that hydraulic oil in a hydraulic oil cavity in the adjusting cavity is input into an adjusting groove from a first pipeline, a sliding block in the adjusting groove is pushed to move, and the sliding block drives an adjusting rod to move; and the blades connected to the connecting blocks are used for machining the prefabricated holes in the casting parts with different diameters, so that the machini