If you are concerned about starting a large clock building project then you might want to try this simple gear cutting exercise first, the DXF files are free to download and try in your Cam software. Just a Gear and a Pinion mounted on a simple frame for you to practice on.
The file has some dimensions in dual metric and imperial formats so as to allow you to check the correct import into your system. The holes and pins are Ø6 mm but can be drilled out to 1/4” if you are working in imperial.
It doesn’t do much much when its finished, but if it runs freely when pinned together then your good to go.
Its real purpose is to give you the confidence to try a larger clock project but also allows you to test different woods and different combinations of feeds and speeds to optimise your machining.