triberman,
If you put ballscrews on it, you will have a problem trying to do manual wheel turning. The force of the cutter or any other external force will move the table! If you try to leave the steppers/servos "locked" and do it that way, it won't work either. If you apply enough force (and it will be quite a bit), the motors will either return the table to original position or it will fault out and freewheel.
When I started this cnc thing, I also thought I "need" to be able to do the manual thing. How wrong I was. I have now gotten used to the keyboard input and my machine doesn't even have handwheels on it.
Art
AKA Country Bubba (Older Than Dirt)