I have one made for the job. It uses simple gearing to get metric pitches down to 0.5 mm. It would need substantial modification to get finer pitches or inch threading in tpi. It works using a crank handle on the spindle, rather than being motor driven.
The gears for the Basic lathe use 17 tooth gears to get close enough to inch pitches, but not many of them. If you have definite pitch requirements check that you can get them with whatever gearing you choose. There are clever ways to get inch pitches on metric lead screws and vice versa, and more obscure things like Mod and DP pitches, without using large gears like 127 tooth.
The U3 uses 1 Mod gears which are easy enough to get. The Basic uses 0.75 Mod, which are quite difficult to find.
Keith
