How to Use a Greenlee Knockout

Use a power drill to create a pilot hole in the surface that you want to use the knockout on. Attach a bit that is 3/8 inches wide and use the drill to create the hole. Place the 1/2-inch conduit onto the 3/8-inch draw stud and insert the stud through the hole you have just created.

Thread the knockout punch onto the end of the draw stud on the opposite side of the wall. The sharp cutting edge of the knockout will be visible. Face this side of the knockout toward the surface that you are cutting. Turn the punch clockwise until it locks into place.

Place the ratcheting wrench over the end of the draw stud and turn it so it is securely in place. Turn the draw stud clockwise slowly and the knockout punch will begin to cut into the surface. Continue turning until the punch breaks through the surface. During this process, the punch may become free and fall through the hole.

Hold the punch with your free hand or place it back onto the stud if it has fallen off. Turn the draw stud back in a counterclockwise motion with the ratcheting wrench while continuing to hold the punch in place. The stud will eventually come loose from the punch. Dispose of the leftover circle that was cut from the surface.