The teaching clock can be a an interesting 3D printing project as it works as a teaching aid on 2 levels.
The first is the obvious one, to teach young children to tell the time using a clock rather than reading the time from their phone. The second is that it uses a novel mechanism to create the 12:1 ratio between the Hour and Minute hands. A description of the Ferguson paradox can be found here http://www.woodenclocks.co.uk/page72.html on my woodenclocks website.
This is a simple build with no requirements for supports, only some adjustment to get the right fits on the main shaft.
Printer: Zortrax M200
I Changed the filament part way through, to print the numerals in Black, I used the Pause setting on the Zortrax to do this at the 88% point. Use finer settings for the gears. Used a drill to clean out the holes to get the right fits in the parts.