Bridgeport Conversion

Hi Guys! I'm new to this CNC, just retired from the military so I
need help from you experts. I plan to buy a used Bridgeport 9x42
knee mill and want to convert it to 3 Axis CNC. I plan on driving
the knee as the Z Axis instead of the quill. I have located a
company that will sell me some quality ballscrews for the XY
(Rockford ballscrew) for around $800. I would like to build the
controller myself to save money since most of the ones I've seen
online run anywhere from $5000 to $14000. I have no idea what size
or type motors to use on the XYZ. From what I've heard servo is
better than stepper? I have no idea what kind of controller card to
use for this application? I will design my parts on either Mastercam
or OneCNC which both are CAD/CAM and then I'd like to run the machine
from my PC in the shop through the controller box? (Is that right?)
Does anyone offer a diagram/plans for the controller and possibly
motor wiring/setup for an application like this??? I would
appreciate any and all help that anyone can give me. Thanks and take
care.

Frank