Before I became a robotic engineer I had an internship designing gears. I thought it would be fun to use what I learned for the 3D design contest. This clock all hangs from the top pinion, which is to be driven by the minute shaft of a clock motor (or 1 rev per hour timing motor if you can find one). The minute wheel, counter weighted by a bolt on the back, in turn, hangs from the hour wheel.
The three printed parts to make this are attached as STL files below, if another format is preferred ask in the comments and I will put them up if possible.
The following Non-printed parts are needed
Some wide heavy washers and a screw to hold them on the back of the minute (lowest) wheel. These act to keep it in place and to counterweight the front.
Additional mounting will need to be made to fit your motor. For ease of integration I have put a pilot hole on the back of the drive cog. It is suggested that a pair of bolts with skateboard bearings be used to support the drive wheel, but I didn't include this because, again, it depends on your motor mounting solution.
Based on feedback I will be making variations and additions to this design, without putting it out I don't know what may be requested, perhaps smaller or larger teeth, different numbers, or some example motor mounts.
I will be updating more soon, please make suggestions when you reply, this Instructable is still a live project for me, and I will grow it with feedback. And if you like it please vote for me in the 3D design contest.