1. Place the two pieces of plastic one on top of the other and tape firmly together, as shown in the photo below. (This will allow you to drill both pieces at once, so the holes will line up later.)
2. Center one of the magnets on top of the taped plastic pieces, as shown in the photo below, and use a pencil or marker to note the position of the holes on the tape. Set the magnet aside and go on to Step 3.
3. Approximately one-quarter of the way from each end of the plastic, mark holes for the nylon screws on the plastic pieces. Put on safety glasses, and drill all the holes with appropriate bits (see photo below), and then pull off the tape.
4. Using flat-head machine screws and nuts, attach each magnet to a piece of plastic. Be sure the exposed faces of the magnets will attract one another (see photos below).
5. Push the nylon screws all the way through the open holes on one piece of plastic. The heads of the screws should be on the opposite side of the plastic from the magnet The threads should extend outward on the magnet side. Tighten the nuts to secure the screws.
6. Twist a nut down onto one of the screws so it’s approximately 1/2 inch (1.25 cm) from the nut at the base. Repeat on the second screw (see photo below).
7. Set the second piece of plastic onto the assembly so the magnets face one another (see photo below). Add the remaining nuts to hold everything in place. When you’re done, set this assembly aside.
8. With wire cutters, cut the armature wire into three pieces, each about 1 foot (30 cm) long. Cover all but the ends of each wire with either shrink wrap or electrical tape (see photos below).
9. Leave one wire straight, bend another wire into a tight U-shape, and bend the third wire into a zigzag, as shown in the photo below. When you’re done, set the wires aside.
10. Insert the batteries into the battery holder.