Looks very nice, flyfishman.
A note on the propwash ones, the mounting thread is very small and short, so you will need a smaller than normal hole and the panel will have to be thin. They also require a lot of effort to turn. Enough effort that you’re going to have to really torque them down to keep the whole thing from turning.
The Elma E37 seem to be a much nicer option.
There is also the Alps dual rotary encoder but it is board mount (not shaft mount) which means a whole different way to mount it.
To be fair that’s another reason I opted to go my own way. I don’t like the look of locking nuts on the front behind the dials. To stop rotation I fasten to the panel from behind using the two side holes on the 3d printed housing. Just finish the volume one now that is similar but also incorporates an on/off switch and ends tops. The shaft coupler has a cam that activates a push switch for the on and end stops that contact features in the housing. This also allows for led to be inside the dial, grounded by the brass tube and an internal wire in the tube contacts the body of the encoder that is used to supply power to the led, all this whire the knob is rotated, almost like slip ring contacts.
Have you received them? How do they work?
Chris
There is a tab on the base of the mounting surface of the encoder to hold it in place; but you have to either print it into your switch support or Dremel wheel a cut if you are using another panel solution. I have found that they become less tight after so me use.