DIY tangential knife cnc

[ryno1984]

Machine description, main features: DIY tangential Knife CNC
Processed materials: foam, paper, cardboard, etc...
Drawings, photos, video of the machine: See photos attached.
Examples of products (photo): N/A
Questions: I recently acquired this tangential knife cnc and the previous owner didn't really know too much about it. I've built a few 3 axis cnc machines now using arduino and grbl based controller boards but this would be my first smoothieboard based machine. I've scrubbed through the config file and downloaded a gcode sender (bCNC from github) and was successfully able to communicate to the smoothieboard to home all axis's and jog each axis excluding the 4th axis that's controlling the rotary knife. I've also downloaded a cam software (DXF2GCODE) that can export dragknife gcode but I'm positive I would have to "find & replace" the axis number the code since smothie doesn't recognize "G40,G41, & G42". I can't seem to figure out how this machine has been configured and would like to keep the integrity of the build (without turning it into another 3 axis cnc machine) because I could really utilize this as a tool in my shop. I would greatly appreciate any and all help to get this thing up and running. I have a theory the original builder may have tied the 4th axis to an extruder output on the board but I really can't comprehend how I would go about exporting the gcode to get it cutting - hopefully the SD files I provided can give you guys some insight. The previous owner did mention how he was never able to get the z axis to lift and turn for angles greater than 20 degrees. If there is any advice on that, that would be great. I have python installed but I haven't used my programming skills in quite some time. Thank you in advance for all your help!

PS- I have 3D printers and a laser engraver that use laswerweb and repetier host so I'm familiar with that software. Just not sure how it could be used to run a rotary cutter if it's using an extruder output.