Practical LEGO Pendulum Clock

This is another LEGO mechanical clock. My goal was to build a truly practical clock out of LEGO: - Efficient enough to run for 24 hours - Easy to rewind - Accurate After running for 2 weeks straight, this clock accumulated just about one minute of error, or about 4 seconds per hour. The weight falls , the weight has a mass of ~600g (11 boat weights x 53 g each, plus a few parts to hold the weights). This is power consumption of 42 microwatts. The clock is ~5 feet off the ground, so it could run for ~60 hours with more chain. It currently has enough chain to run for ~35 hours. This clock is about 6 times more efficient than my last clock ( This clock is easy to rewind because it is driven by a freely hanging chain (tank treads). Rewinding it involves simply pulling the free end of the chain back through the clock. An interesting design feature is that the chain is a loop, to avoid the change in drive weight as the chain feeds throu