This is a functional model of the pendulum clock said to have been designed by Galileo. This is designed to be used as a historical teaching model for hands-on student interaction but I make no claims of its historical accuracy. I simply made it based on his drawings. Students learn about gears and gearing, stored energy (through the rubber band), the escapement mechanism, and the properties of the pendulum. The pendulum in this clock is designed to enable students to explore how weight and length impact period by making it easy for students to move washers or large nuts along notches on the pendulum (full length and half-way up).
More detailed assembly instructions will be posted shortly. This is designed to be cut from 1/4" (5mm) plywood (I've found that Home Depot's new Purebond plywood works great). It is designed to work with 1/4" dowels but be warned the holes for the gears are very snug (on purpose). The frame is designed to use nylon washers to reduce friction with a 1/4" ID and a 3/8" OD.
I've included new pictures to help with the assembly. Look at the washer spacing for the pendulum and escapement mechanism. Also note that the escapement requires a piece to be glued to it above to enable it to work. It is the small rectangle in the plans.
Finally, I recommend playing a little with the exact placement of the two catches on the pendulum. This model is designed to fit very snugly around the 1/4" dowel and I would adjust it manually until I got it to work correctly and then I'd use a spot of super glue to hold it in place once it is working.