What are the problems to do it ?
Mainly backlash and a bad understanding of the way servo work.
The backlash must be smaller than the resolution of the encoder !
Our machine is a Lagun FTV2 manual that we have transformed 100% ourself.
The DRO read an encoder of 20µ lines (so 5µ resolution)
after having try to make a roller screw we (for the time been) give up and buy 4 chinese C7 ball screw with 8 nuts !
25 mm lead 5 mm
the screw was off line by a generous 2 mm and we straight it to 1/100 mm
We the machined it ourself ( my friend is very suspicious about making precision work for little money) the surface is hardened so carbide is a must.
we then use it for a while with only one nuts. the backlash was 2 (X)and 5/100 mm(Y) all coming from the nuts (we have angular bearing and the belt is very tight)
with such backlash forget about linear encoder