Lloyd, my opinion is worth $0.01, but I feel that I have to state it.
CNC retrofit of a machine that is built as a CNC machine, is a
COMPLETELY different type of project than a CNC retrofit of a manual
machine.
If the difficulty of the former is 6 on the scale of 1-10, then the
latter is 9-10.
You have to be essentially a CNC machine designer, make a lot of
things fit that do not want to fit, make and mount a lot of brackets,
doodads, switches. Also you need to buy servo motors.
It all seems simple conceptually, until a) you start doing it and b)
make some mistakes that you realize late in the game. For sure it is
NOT cheap, if you price your time at $5 per hour and up.
I agree that a CNC lathe that is not totally clapped out, is harder
to find that a mill or a VMC.
I may be overstating my case or just not experienced enough to breeze
through that sort of thing. But somehow, I feel that retrofitting
manuals machines is not nearly as cost effective as taking a CNC
machine with a bad control.
i