All of Itchy’s parts work individually, and Co-squid found a tool chain that will drive the Arduino from output from Inkscape. Inkscape has gcode extensions. Of course it has. So now, I just have to put it together. The machine went from jerky, jumpy bouncing to having some smoothness of movement today.
Co-squid goes back to her house soon, and I’m going to have to work out where to put what I am calling Itchy and she is calling Murderbot. Given the fragment of scalpel I found in the second hand parts, I think it already was a cutter. I’m going to find some way of keeping that bit of scalpel in there.