So, I started a new software project, this time to machine void free finger or box joints. Such joints in general are easy enough to do on a CNC but due to the bit radius usually require dogbone fillets to avoid interference. I wanted to avoid that and have the option of varying decorative finger patterns including true half-blind joints. I started about a year ago and gave up because I could not figure out the algorithms for creating the tool paths (my trigonometry is not up to snuff, I guess). Lately I picked it up again and had some success. The user interface is almost done (see below) and I am in serious debugging mode. I made a few test cuts and will probably try a complete box over the weekend. If everything works out I will probably publish a Beta version in a few weeks. I am quite happy with the result so far.
Toolpath simulation (using other CAM software):
Practical result (I need to flatten the boards better to avoid the gaps):
Another test: