Ok, I now have the stepper motors, psu and driver board all wired up to the computer, running a demo version of Mach 3. I have control of the motors at the required speed. (stage one complete!) Next comes the rails and the linear drives - which is where I could do with some advice.

Currently thinking of using 20mm supported precision rails for x, and possibly y axis. Considering the part at the following link. My question is will the plasma dust cause problems with this rail? http://www.ebay.co.uk/itm/SBR20X2204...item19c694e118

The drive will be via Mod 1 rack, on both sides of the X axis. One single stepper motor for x, connected to both sides via a cross-shaft inside the gantry (probably box section) Motor will be geared down via pulleys and timing belt. Y axis also via Mod 1 rack and the same gearing. Again, can anyone advise how this will likely perform when subjected to plasma dust?

Z axis is likely to be bought in. Considering this one http://www.ebay.co.uk/itm/NEMA23-75m...item48410ad57a. Will then add a floating head setup and control via Mach 3. Any comments / advise please from anyone who has done similar

Final thoughs for the moment are regarding limit and home switches. I want to use something reliable and with repeatable acurracy. Any suggestions?

Thanks in advance

Geoff