The top is an old door from a schoolhouse in Wisconsin. Originally there was a tack board material on it for thumbtacking papers. The door knob has a lever mechanism that moves a pin in and out. This way the door could open or lock in place.
The gears are from an old farm corn shucker. I had to cut what you see here from a much larger mechanism.
Yardsticks and pallets make up the right leg, which is typical of some of my other work.