You will need to drill a hole in the side of the nut to accept the magnet bit holder. Use a center punch to start a pilot hole directly into the center of one side of the nut. Drill a 1/4in hole into the nut. Once the hole is drilled you will need to file the hole into a hexagon that matches the bit holder. Be patient, this takes a while. You want the hole to be as tight as possible. You should nee to use the hammer to persuade the bit holder into place.