Still plugging away at getting the gear box aligned with the motor. I can sometimes get them lined up pretty well, but every time I make a tweak to try to improve it, it most often gets worse.
The video below shows significant misalignment, but it is useful to show what I am fighting.
The brass coupler I ordered a while ago finally came in so the connection to the gearbox is pretty clean. Also the aluminum sprocket for the gearbox arrived. It did not have a 6mm hole to fit the gearbox shaft, but I knew that when I ordered it (I bought this one because it was cheap) Fortunately it was very simple to drill the hole to the correct size, and the set screws still work perfectly.
The gearbox mount is bolted to the motor mount with large clearance holles, so it can be positioned vertically and horizontally to align the shafts. However this is a very touchy adjustment, being off by the thickness of a sheet of paper creates a large wobble. I expect I can get it aligned well enough to work - it only has to run for about 1 second every 10 minutes.
The video is uneditied - no titles, not great lighting, just letting the camera do its thing. I am curious to see how it shows up online. I believe the camera is set to record 4K video. Normally I convert it down to lower resolution, but this is a short video.
My brother finally convinced me to use a lapel mic with the camera (by giving me one), so the audio in the video should be a little better as well.