Welcome to the frustrating world of wooden clock making. It can be tedious and frustrating but the rewards in job satisfaction are huge when you achieve a working machine, at least they were for me. I've only completed one clock and you can see it in the making here
Clock WIP. I'm on my second clock at the moment but it has been in limbo for many months. It's basically working but it needs a final burst of enthusiasm. That may well happen now as all my other projects are now finished.
With regard to gear material and cutting. I invested in a
semi decent scroll saw and a
Belt Sander. I found that the scrollsaw was not the best m/c for cutting gear teeth but it is good for cutting the many other shapes involved. I now cut away most of the gear wastewood with my bandsaw and the sand down to required profile with the sander.
As far as plywood goes I have invested in a complete sheet of 6mm B/BB birch 5-ply. This has one completely clean side and the other side has knot repairs which can be avoided or accepted for the back side of the gear. I haven't come across any voids in this grade of ply so far.
I would recommend getting hold of any grade of ply just to have a go and get the feel for the making process. In the meantime have a hunt round the web for sources of ply in smaller sizes, however it does become quite expensive and you won't be able to stand many failures which will inevitably happen.
When I was doing my initial research I didn't come across any dedicated forum. If you would like to continue with a more detailed discussion via email I'd be happy to do that. Send me a PM if you wish.
Brian