A few years ago, I made the workings of a clock with 3 coaxial hands. After a long time, I decided to try to get it to actually run on time. I attached an escapement gear and an ajustable pendulum to regulate the time. It has a 1 second period to make it easy. Then, to turn the clock, I put a heavy weight on a chain, followed by a lot of gearing down to last a while. It worked, but I found that to have a clock that lasted longer than 5 minutes, I would have to use a weight so heavy it started to warp my parts. So, after figuring out the pendulum worked great, I decided to opt for a motor and give my clock a body.