11-14-2012, 07:04 PM
Dave, I think Arvid"s idea should work. If you put enough air pressure on the cylinder it would lift the ball nut off its thrust bearing. The ball screw will always see the table weight above the nut, below the nut it sees the lift of the piston. The difference is what the nut has to lift.
Free advice is worth exactly what you payed for it.
Greg
Greg