I own the WM16, and i haven't considered a mod like that because i'm mr manual with these machines, backlash isn't a problem because i'm reading the movement of the DRO register rather than the indents on the handle, the only reason i could think of why you'd want ballscrew slide is because you want a CNC mill, You want to talk to Mr. John stevenson, another forumite who specializes in these modifications.
And yes i've seen the same said before too that you can't do this without another mill, something along the lines of there not being enough room for the mounting to fit in the casting. I would take it for a dead certain, that it will need machining to fit properly.
Michael W
Edited By Michael Walters on 14/10/2016 17:05:44