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MATERIALS
The Materials Required to Build a Safety Pin Motor
BASE qty. 1 ¾" x 3½" x 4½" clear pine
BATTERY qty. 1 C cell
BEADS qty. 2 plastic, 6mm
MAGNETS qty. 2 3/4" diameter x 3/16" high, ceramic
RUBBER BAND qty.1 to fit battery
SAFETY PINS qty.2 #3 pins, 2" long
WIRE 4 feet 22 gauge enameled magnet wire
BASE
The motor is built on a piece of ¾" thick clear pine, 3½" wide and 4½" long. Many craft shops sell small wooden plaques for craft purposes that work well. The Safety Pin Motor Engineering Design Team purchased a piece of 4" clear pine and cut it to length. (4 inch pine boards actually measure 3½ inches across.) You need to stick two safety pins into the base so avoid wood with knots.
BATTERY
The motor uses a C cell battery. You can use a smaller AA battery but they won't last as long.
BEADS
Beads are used to keep the motor armature centered. You can get them in any craft shop. Beads that are too large to fit through the loop of the safety pins work best. Plastic beads about 5mm in diameter work well.
MAGNET
The motor uses 2 ceramic magnets, ¾” in diameter and 3/16” high. Just about any ceramic magnet of reasonable size will work. They are commonly available in craft and hobby shops.
RUBBER BAND
A 1½” diameter rubber band is used to hold the battery between the two ends of safety pins.
SAFETY PINS
Two Safety Pins form the armature and battery holder. They are available in most craft shops, usually in the bead section. The pins are 2¼” long and are sometimes labeled #3 safety pins.
WIRE
The coil or armature is made of 22 gauge enamelled magnet wire. In the United States, Radio Shack sells a package of three different gauges of magnet wire which includes a 40 feet roll of 22 gauge wire. Many craft shops also sell 22 gauge copper wire in various colors for making jewelry. This craft wire will work but the insulation seems to be a plastic coating which does not work nearly as well as “real” magnet wire. If you use craft wire you will also need some nail polish to make the motor work. See the instructions for details.
HOME CONSTRUCTION LINKS HOW IT WORKS