Chinese lathe | Model Engineer
What gears do you have? If it is like my Sieg C3 mini lathe the Manual lists, in various places, 2 x 20T, 30T, 35T, 2 x 40T, 2 x 45T, 50T 55T, 57T, 60T, 65T , and 2 x 80T Against the time when I want to cut Imperial threads, I bought a 63T, (and an extra 45T for some reason. ) For the finest feed rate, the manual advises Driver 20T: Stud 80T/20T Leadscrew:80T This gives a 16:1 reduction, so a 1.5 mm Leadscrew will produce a feed of 0.9375 mm / rev of the chuck. If you want an even finer...
Source: model-engineer.co.uk