[AKFALAR]

Will this system have problems with backlash?

[spoiledbrat]

As long as the two ballnuts are being pulled apart from one another (or pressed toward eachother), backlash can be eliminated. A truly great system is not rigid, but has more of a spring like force between the two nuts. Tension is then set as appropriate (20lbs? 70 lbs? consult the manufacturer). With the spring, the nuts are then able to "squeeze" past the tight spots (or imperfections, dust, etc) on the screw, and backlash is eliminated.

If you are going with a rigid setup like this, I think it might be cheaper just to load over sized ball-bearings into the nut, and forget the idea of two nuts.

Just my opinion,

Rob