So I am new to this and looking to build a small wood cnc router, I was looking at the 40x40 kit and after about a week of research I see many of these kits use a stepper motor on both sides of the main table with a belt drive. how are both motors controlled exactly the same? I was looking to control mine with a GRBL shield and an arduino. but that only has 3 motor drivers. Would it make more sense or be possible to have a single ball screw in the center with a cross beam under the table instead of the 2 belts? Thanks in advance for the help.