I'm looking at building a machine some time this summer but had a question about Rack and Pinion systems. Looking at the system from CNC Router Parts, would I need to mirror each side of the machine to insure that nothing gets bound up? I've looked at several Lead screw systems that had motors on both rails for the X-axis, would this work the same way with R&P systems?
The cncrouterparts R&P is designed to drive from the side of the gantry, not the middle, although I suppose it's possible to figure out a way to do that. Driving from the side, you drive both sides, using two of them. I have a FLA-300 that does that. Two rails, 4 carriages, two R&P drives. They are mirrored, so the stepper projects outwards on both sides.
I designed my own R&P system but I researched the CNC Router Parts design and built mine somewhat like it. I use 2 drives on my X axis, and one for the Y. The Z is driven from an acme screw. My X axis is 50" wide, so to assure that my gantry remains square to the Y I had to drive it with to motors. This has worked extremely well, I am very pleased with the power of the system. I would HIGHLY recommend the the CNC Router Parts drive system, coupled to a G540 drive and their stepper motors you will be very pleased.