Three-Stage Clock Gear Chain

Three-Stage Clock Gear Chain

This is one of a set of three clock models that show how the necessary 60-to-1 gear ratio between the second and minute hands in a mechanical clock can be achieved in a practical way. This model shows how it’s done in three stages: first 7 teeth to 21 teeth gives 3-to-1 reduction, then 7 teeth to 28 teeth gives a 4-to-1 reduction, and finally 8 teeth to 40 teeth gives a 5-to-1 reduction. 3 times 4 times 5 gives 60-to-1.

Our Two-Stage Clock Gear Chain model shows how the same can be done in two steps, which uses fewer gears, but is actually larger overall. (Doing it in one stage, with a 6-tooth and a 360-tooth gear, is theoretically possible, but crazy big, so we offer it only on special order.)

Our Folded Three-Stage Clock Gear Chain model uses the same gear arrangement as the Three Stage model, but folded in on itself to place the second and minute hands on the same axis, as they normally are in a real clock. This is more realistic, but much hard to follow if you’re trying to understand the logic of the gear chain.

Finally, our Electric Clock model uses the three-stage design, and adds a further gear chain for the hour hand, and a battery-powered watch movement to drive the second hand, resulting in a full working clock. More practical, but not as much fun to use like a fidget spinner!

Our Complete Clock Set includes all four models for a discounted total price.

Your model will arrive attractively packaged with all the necessary parts (including a screwdriver and two wrenches). The kit screws together in about 25-30 minutes, and does not require any special model-building skills. A detailed, step-by-step assembly video is available on our instructions page.