G'day Ben.
I've just came across your channel when looking for videos on mechanical television as it is a big interest of mine. Anyhow I watched both episodes and totally enjoyed them and learned some things I didn't already know such as how the flying spot scanner actually works in mechanical TV! Sorry to see you were unable to get it working to display an image, so I felt prompted to share some of what I know in building mechanical televisors as well as resources you can look into.
Firstly here's some very useful sites you can visit to learn more on building mechanical TVs as well as conversion software to output mechanical video for testing:
NBTV forum Narrow-Bandwidth Television Association • Index page (this is a goldmine of project info for all sorts of mechanical TV/camera builds of many sorts from many members including myself, I highly recommend you join up and check out the projects on there)
NBTV Narrow Bandwidth Television Association NBTV Handbook (this is the main site for 32 line NBTV standard mechanical TV)
Gary's NBTV mechanical TV software Gary's web site (This Aussie guy has developed software that converts any video and pics into mechanical TV signals of various formats to display on various mechanical televisors and also software to display a mechanical TV signal on computer too, his software is awesome for testing mechanical TVs)
Now my experience with mechanical TV/camera building, I have built simple Nipkow disc televisors without sync circuits and I use Gary's software to display images and I manually sync the disc with my finger as a brake, that is the simplest way to simply get a mechanical TV to display an image, here's a couple of displays I made I've featured on my website Untitled (32 line NBTV cardboard paper Nipkow display), Untitled (32 line NBTV plywood disc Nipkow display). Later on I made a 32 line mechanical TV/camera both utilizing the same LP record disc, the beauty of this is you don't even need to synchonize it because it's all on the one disc, the disc consists of 1.5 spirals and 48 holes so what the camera captures get's displayed on the lightbox monitor side at the same time, I can run it at any speed and it will produce an image all the same, anyhow my 32 line NBTV camera/monitor project log can be seen here Narrow-Bandwidth Television Association • View topic - New NBTV camera project there's 11 pages worth of construction/testing logs, also I made many vlogs on constructing this TV/camera on my channel https://www.youtube.com/user/troysvisualarts just search NBTV camera, here's a good off the monitor camera capture of the unit in operation https://youtu.be/ZY9mwXC--ro I used an ancient B&W tube video camera for capture as it has image persistence to lessen the flicker. My version of the camera is not a flying spot but a direct lens focus to nipkow disc and behind it some condenser lenses and a dome sensor to pick up the light. Also the holes of the nipkow disc are drilled with a needle to be very small opposed to being larger like yours, this ensures a finer detailed sharp image but at the cost of light sensitivity on the sensor and brightness on the monitor side.
I hope this will be all helpful when you revisit your mechanical TV and camera project again. Your project has given me a clearer picture on how a flying spot scanner nipkow camera works and has inspired me to try out building a flying spot scanner myself, I so gotta build one in the near future. Also I like the belt drive synchronisation idea too, another idea would be to place 2 discs on a spindle and belt drive the spindle from one motor, this is what Australian radio experimenter Chris Long did building his nipkow camera/TV apparatus https://www.youtube.com/watch?v=6ST9E8oEkpI .
Anyways best of luck with the project, look forward to a future video on it.
Cheers
Troy