Dear Members: I am new here, so if this is not the correct place or manner to pose this question, please forgive me and show me the right way
to proceed...

I am contemplating, for many years, converting my RF31 clone to CNC... yes, I know: round column - ugh... but this is what I have and
she-who-must-be-obeyed will not let me buy a better mill...

Initially, I intend to convert only the Z axis, since this is the one that gives me the most trouble, with the awful backlash in
the rack-and-pinion mechanism.

But, all the conversions I have seen lately simply adapt a stepper to this inherently flawed implementation of the Z movement.

Finally this is my question: has anybody seem a Z-axis conversion on one of these machines that replaces the rack-and-pinion with
a ballscrew/nut? I believe it would have to be a rotating nut design, and I remember seeing, many years ago, a beautiful conversion
in which the guy placed a rotating nut inside the head of the machine, but I could not find the post nowadays...

Has anybody seems this post or any other, or has a suggestion about converting the Z drive on a RF31 to ballscrew/nut?

Thank you so much for your attention.

Arquibaldo