This is a working wheel cutting engine based on historical designs. "Wheel" is the term that clock-makers use for larger gears, while "pinion" is the term used for smaller ones. This gorgeous machine was built by the talented Kevin Wright. Wright designed the engine to cut the gears for a mechanism he wanted to build. Basically, he built a machine to build another machine!
A metal blank, brass in this case, is mounted to the top of the spindle in the center of the engine. The large circular disc below is an indexing plate. A spring-actuated lever drops into notches in the wheel allowing wheels with different numbers of teeth to be cut. The cutter is mounted to a hinged assembly above the blank. When you turn the crank, the cutter spins. The spinning cutter is then lowered into the blank to cut a notch in the gear's edge. The index wheel is used to rotate the blank a specified amount, then the process is repeated. By this method, a complete gear may be cut.
While Wright has modern tools to cut gears and pinions, he wanted to experience what the clock-makers of old went through. They built wonderful precision mechanisms with tools very similar to the one he made. He says it is very satisfying cut gears without the use of electricity. I imagine so!
See more mechanical marvels by Kevin Wright on his web site.