Z axis conversion

In my opinion, gentlemen (and ladies) the "knee" will not make a
good "Z". The quill bolt ons I agree aren't great, but you get to
messing with that knee and you'll regret it. There is a bevel reduction
gear in there (that's about 2:1) so there is some backlash. Even though
I think Smoke is right about not needing a anti-backlash nut. So, you
have to get all that out of there and fit a motor up inside the knee
somehow? I don't think so.
Not to mention you have to move 3 big castings, the knee, the table,
and the saddle. All together 500 pounds at least! Crank on that knee
up and down several times a day, it's a good workout. You're going to
put an awful load on any reasonable sized motor.
The Knee Way? No way!!!!