How did clockmakers and watchmakers arrive at the divisions in their gear wheel teeth before the invention of sophisticated tools? We can create very accurate divisions using only simple methods. In this part 1, I show how this is done, as also demonstrated at a horological exhibition last year. In part 2, I show how the teeth are actually cut and filed, by hand.
This process has been used for at least a few thousand years. I first learned of it by watching Michael Wright, of the London Science museum demonstrate this on the BBC. The method has also been published in German and English horological reference books.