My bucket_mill.py project ( https://github.com/nathanielstenzel/bucket_mill ) seems to do okay with the toolpath. Unfortunately, the chuck on my router warmed up and decided to loosen up its grip on the bit. I did not notice that happened so a little bit later it snapped off and shot at the wall. I am lucky it did not fly at me. The bit cost $8-15. I forget the exact price. I imagine the bit would not have heated up as much if my chip size was bigger. Maybe I should have tightened it down even tighter too. I thought it was plenty tight.
My Shapeoko also seems to be missing a guide wheel, so I will have to get another bearing so that I can fix that.
I just added a cut-depth parameter for rough cuts.