you usually think of turning a screw, a table leg, or a toothpick. [Uri Tuchman] had a different idea. He wanted to make a clock out of the gears used in the lathe. Can he do it? Of course ...

The core of the clock is the escapement, a linkage which the pendulum can only turn in one direction. As the pendulum swings once per second, it lets the escapement gear turn one notch forward at ...