I am trying to devise a method (3d printing or injection molding) in order to turn a potentiometer via a thumbwheel mechanism.

Take a look at this picture, from an old commercial product that I am trying to replicate:

enter image description here

The purpose of this mechanism is to turn a potentiomer. The user turns the gear like structure at the edge. Here is another picture:

enter image description here

I am not able to break it apart without breaking it, but it seems some glue is used. There are apparently 4 structures, although they could be less, as some could be joined (one part instead of two, for example).

There is the outer gear like rotating structure (thumbwheel), there is a long lateral axis, and two circular things at the bottom of the axis...

Anyone familiar with this mechanism so I can replicate it? Is this a snap-fit mechanism? Does anyone know how many parts does this consist of?

  • $\begingroup$ This post would definitely benefit from slightly better pictures. Adjust the focus and use, more light and use a tripod or atleast lean on table before taking the picture. $\endgroup$
    – joojaa
    Aug 4, 2023 at 22:08

1 Answer 1


As you say, it's a custom thumbwheel potentiometer.

enter image description here

Figure 1. Results from Google Image Search for thumbwheel potentiometer.

Large open-frame potentiometers use to be commonly available but don't seem to be now.

If I was to try to make one I would try to pass the shaft through the potentiometer and support it on both sides so that any stress is not applied to the pot but taken by the shaft and case.

  • $\begingroup$ Thank you and sorry for the late reply. Can a trimmer style potentiometer be used with a plastic mechanism like this, in order to achieve the same effect? $\endgroup$ Aug 29, 2023 at 7:29
  • 1
    $\begingroup$ If you find a suitable trimmer, then yes. $\endgroup$
    – Transistor
    Aug 29, 2023 at 19:03
  • $\begingroup$ Thank you for your help! $\endgroup$ Sep 10, 2023 at 19:44

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