Worm Gear

Sat, 23 Oct 2010

A worm is used to reduce speed. For each complete turn of the worm shaft the gear shaft advances only one tooth of the gear. In this case, with a twelve tooth gear, the speed is reduced by a factor of twelve. Also, the axis of rotation is turned by 90 degrees. Unlike ordinary gears, the motion is not reversible, a worm can drive a gear to reduce speed but a gear cannot drive a worm to increase it. As the speed is reduced the power to the drive increases correspondingly. Worm gears are a compact, efficient means of substantially decreasing speed and increasing power. Ideal for use with small electric motors.

Make your own working worm gear model.
Turn the handle and the worm turns! The 24 tooth gear turns at 1/24 of the speed of the handle.

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Comments (4)

  • tombeutel March 4, 2011 at 3:22 pm

    Good morning Rob, or

    Good morning Rob, or afternoon where you are. I am working on a design using a worm gear and would like to make one that is slightly smaller than the one on your site. Can you recommend a good source for "simple" worm gear design?




    • robives March 4, 2011 at 4:28 pm

      How much smaller? You can

      How much smaller? You can vary the size of the file on the site by changing the printing scale or editing the file.

      • tombeutel March 4, 2011 at 10:19 pm

        Thanks, Rob. It doesn’t need

        Thanks, Rob. It doesn't need to be much smaller, just a little to accommodate a 1" diameter 8-tooth gear. I'm debating whether to use the worm gear for a 8:1 reduction or use a couple of spur gears for less of a reduction. The worm gear works so smoothly. I haven't tried the other gears yet.

  • Anonymous July 16, 2013 at 11:38 am

    Hi Rob, Where can i find

    Hi Rob, Where can i find examples of applications in products or machines around us for all of these mechanisms, especially for worm gear? and your website is very helpful my whole college uses it. thank you.

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