thanks boyan its an interesting thread so far :) i was originally going for nema 23's 3nm on a 2:1 ratio. i cant remember where i read it from but are servos alot more complicated to use then steppers? my actual goal is to get as much resolution as i can while keeping the machine nice and quick, i had in mind with the nema 23's running 2020 screws on a 2:1 rotating nut so i get some of the speed from 20mm pitch and resolution from a 10mm pitch. my dream goal was to have a resolution of a 5mm pitch but still have a really quick machine but ive learned thats not possible on steppers and im not quite sure yet if its possible on less expensive servos.

cheers

Ash