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.
Materials:
- 1/4" plastic sheet (eg. Polycarbonate)
- 1/16" diameter braided cord
- small rubberband
Procedure:
- Use a hole saw on a large drill press to cut a disk slightly larger then the finished size of
the pulley.
- Drill ahole in the center of the disk. The size of the hole should at least fit 0.25 inch or 6 mm bolt.
- 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.
- Place this assembly in a lathe chuck. A three jaw chuck can easily grip three faces on
the nut.
- Turn the pulley to the appropriate outer diameter.
- Use a cut-off tool to cut a groove 0. 100" deep in the edge of the disk.
- Remove pulley from the lathe.
- Carefully place the small rubberband into the groove so that it is not twisted.
- 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.
- 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.