I've always had trouble getting my tool path to display large enough to be very helpful. It occurred to me that Mach may think my machine is 20 feet wide and 30 feet long. And so the material being milled shows up the size of a postage stamp. In reality, my machine is about 20" x 30", and my material is about 5" x 10". Can you help? As a secondary request-- I've messed up my colors and there's not an option to reset to default. (Config > ToolPath > Colors) If you can help with that too, it would be great. Thank you.
I know it is an old post
BUT since the question is high is GOOGLE SEARCH- it is better to answer for even newbies & others to know.
Solution to define the router table size
is to define SOFT LIMITS from 0 to within 0.1" of far end physical limit switches for X & Y axis.
MACH3 now knows your table size.
Under config | General Config, lock DRO's to setup units is unticked in my case because I run Gcodes in both G20 (inches) and G21 (mm).
(MACH4 is BETTER as it will tell you in the DROs whether you are displaying in INCHES or mm.)