How to Make Plastic Gears

Make Plastic Gears
••• Illustrations by Andrew DeWitt

Gears have been used for hundreds of years as a way to make small machine components move. Gears are used in clocks, watches, gates and even small toys. Now you can make your own plastic gears for home projects. You can use these as replacement parts for gears or for custom clockwork machinery that you are making. Create handmade moving gifts for special occasions or use the gears as part of a science project to show real mechanical motion in action. Follow along with these steps.

    Trace a gear pattern on a sheet of plasticard with a pencil. Draw guidelines using a compass and ruler to make sure the pattern is laid down correctly. Use the Sharpie to trace over the pencil once the pattern has been drawn correctly.

    Cut around the gear with a pair of scissors. Start the scissors as close to the pattern as possible. Leave around an inch of extra plasticard around the gear pattern. Do not try to cut the individual gear teeth with the scissors. This could result in uneven or warped gears that will not fit together.

    Cut the teeth out of the pattern with an X-Acto knife. Press down firmly in the corner of a gear tooth and rock the blade outward to start the cut. Continue the cut until the blade has cleared through all of the plastic. Repeat the process, always beginning at the corner of the gear tooth and moving outward. Match the pattern exactly.

    Sand the teeth of the gears gently. Remove any excess plastic from the gear teeth. If any teeth have been cut too large, refine the shape with the sandpaper. Wrap the sandpaper around a thin bar of metal or a metal ruler to give the paper shape and allow for easier sanding. You may have to cut the sand paper to a smaller size so that it is easier to work with when folded.

    Clean the gears and match them together to make sure they fit. Place a pencil or other long cylinder in the gear and spin it against the other gear to ensure they are in working order.

    Things You'll Need

    • Plasticard
    • Scissors
    • X-Acto knife
    • Pencil
    • Sand paper
    • Gear pattern
    • Sharpie
    • Compass

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