– How do vintage watches have such incredible tolerances?

Question

I see vintage watches repaired. When the case is opened the movements are so well-designed and engineered, with gear teeth cut to the 0.1 MM level and thin, perfect jewels. How is such mechanical precision possible from decades ago?

In: Engineering

Answer 1

[https://en.wikipedia.org/wiki/Antikythera_mechanism](https://en.wikipedia.org/wiki/Antikythera_mechanism)

First Century BC