Design Cookbook: Pulley Drives

Cookbook Index

Pulley drives are useful as they transmit rotational motion and torque from one location to another. Pulleys
of different size can be used to achieve a desired angular velocity ratio. The belt can be crossed to reverse the rotation.



  1. Use a hole saw on a large drill press to cut a disk slightly larger then the finished size of
    the pulley.
  2. Drill ahole in the center of the disk. The size of the hole should at least fit 0.25 inch or 6 mm bolt.
  3. Put a bolt through the hole in the disk, then put a nut on the bolt and tighten. This bolt will act as a spindle to allow you to mount the disk in a lathe safely.
  4. Place this assembly in a lathe chuck. A three jaw chuck can easily grip three faces on
    the nut.
  5. Turn the pulley to the appropriate outer diameter.
  6. Use a cut-off tool to cut a groove 0. 100" deep in the edge of the disk.
  7. Remove pulley from the lathe.
  8. Carefully place the small rubberband into the groove so that it is not twisted.
  9. Attach the pulley to shafts or wheels as shown in other sections of the cookbook. The distance between the pulleys should be adjustable to allow tensioning of the belt.
  10. To make a continuous loop belt from braided cord, heat the two ends of the cord with
    a soldering iron until the ends melt. Ouickly press the ends together and roill between your
    fingers to make a smooth joint.