A knockout punch, also known as a chassis punch or a Q-max, is a hand tool used to punch a hole through sheet metal. It is a very simple tool that consists of a punch, Die, and screw.
To operate, first a pilot hole is Drilled of the same diameter as the screw of the knockout punch. Then the Die is placed on the screw and the screw is inserted into the pilot hole. The screw is then threaded into the punch and the screw tightened until the punch is drawn completely through the sheet metal.