Automatic centering drill jig

The utility model belongs to the technical field of technological equipment design, and particularly relates to an automatic centering drill jig. When a cast shell flange is fixed and positioned, the situation that a drilled hole is inconsistent with the wall thickness of the shell flange in appearance often exists. An automatic centering mechanism and a pressing mechanism are installed on a drill plate, a threaded block is fixedly installed on the end face of the left side of the drill plate, a left movable V-shaped block and a right movable V-shaped block are installed on the lower side of the drill plate in a left-right sliding mode, and a pair of pull rods extending out of the right movable V-shaped block penetrates through the left movable V-shaped block and then is connected with a bearing plate. Two parts of threads on the ball head rotating screw are in threaded connection with the bearing plate and the threaded block respectively, the thread turning direction of the bearing plate is the same as that