Methods for ball screw driving Z axis on Bridgeport type quill

I am thinking of servo driving the Z axis on my current 3
h.p. mill cnc conversion (x &y axis Gekko g320 servo drives
and 210 in. oz. motors). The quill is similar to the
bridgeport style, a pinion gear driving a rack on the quill
and a quill handle but w/o a draw bar. The end of the pinion
gear opposite the quill handle has a 3/4"x 6"L shaft that
comes out the other side of the quill housing.
Is there any workable way to drive the z axis through the
pinion gear and get good 3 axis results, i.e. be able to
mill profiles?
Any ideas on how to attach a ball screw to the quill?
Besides the quill moving the whole quill gear box and motor
slides up and down on a set of ways but it seems very heavy.

Bob