Hi Mark, I have a different sized machine so I don’t know if my comment will apply or not.
I’m using a spoil board that is larger than the size I’ve got set aside for it. The head on my machine can actually travel farther than the size of the machine. As an example, if my machine were 48x48 (it isn’t but lets pretend it is) then the center of the cutter can easily reach 48x48. Notice the center of the cutter can reach those dimensions. It is actually farther than that in real-life. If there were not the extra room (which is genius on the part of AVIDcnc) then a 1.5in diameter cutter would clear out a spoil board of 48+1.5x48+1.5. And then there is the extra room on top of that.
I’m almost wondering if maybe it isn’t that the g-code set up to run that tool path wasn’t set up a bit to conservativly, as on the bigger machines at least, there is a small bit of extra travle (like an inch or so) beyond the advertised size so a 4ft machine can actually cut around the edges of a 4ft part.
Just thinking out loud there, and I’m definitely not an expert on this stuff, just relating my experience with one of their bigger machines, but I suspect that they have done this on all machines… (IE, they can move to slightly further than then full envelope?)