I have three of my machines set up with VFD and I have used 22 mm push buttons and rotary switches. The problem is that the rotary switches tend to move over time. I know that there are locking washers available with tabs to prevent the rotation in the enclosure. I cannot seem to find a source for these and they do not come with the switches. Apparently I am calling them by the wrong name because I cannot find them with a search. Where can I find these washers or at least what is the proper name to search?