This is a wooden geared clock I built that is roughly based on a design I got from Brian Law.
His design used a single weight to drive the clock and the original design would wind down in lees than 8 hours.
I added a second weight, and increased the distance between the floor and the weights, which increased the run time to well over 13 hours.
The majority of the gears were cut by using my CNC machine to create accurate gears that meshed in a precise manner.
All the gears are mounted on brass rod that are in turn mounted on roller bearings. It seemed that any friction would cause the clock to stop.
The weights are recycled window sash weights that weigh about 7 pounds each.
For better look at the working clock, go to: https://www.youtube.com/watch?v=PaI9liHxfKc