A very good idea. A friend of mine used something similar :
https://sites.google.com/a/astronomo...lesc%C3%B3pio2
One of the problems I see and also have in my project, is that if you want 360 degrees of rotation, the size of the threaded rod is very large (ie worse in my project). Anyway, in both projects, you can make 360 degrees, leave the size of the threade rod compatible with the size of the circumference of the disc