Hi Rj,
So first to start, stl's dont carry any "unit of measure" information... just dumb "units"...
So something about the situation is assuming a unit of measure.
So bobcad's internals i "think" are working in the metric system (most cad etc)
If i "open" bobcads exports in some other programs, they open as an mm file. I can "import" them into an inches doc to get what i want...
With that said, here are a couple things to try, since i dont have your printer.
1. Look for an "import" as opposed to an open, in the printers interface.
2. Try setting a custom unit in bobcad before the export. So settings-part-units-custom... try 1 unit equals 0.0394... (or vise versa) to see if that affects the models scale in the printer. (Aside from looking deeper at printers settings for scale factors etc)
3. Bobcad exports binary stls. It "shouldnt" affect this, but who knows. There is a program installed with predator you could try. It is called "stlfix" in the program files (x86) folder-predator software- (subfolder "vcnc" or something like that. Not currently at my computer) try open an stl then do a save as and select ascii stl as type and see if that file makes a difference...
4. Lastly, just set machine as mm and cut that way. That would be the fastest way to get setup without having someone there to help you track down the disparity.