I added some code to my PCB editor to make it output a file of gcode commands to drill a hole wherever there is a hole in the PCB. With that, I was able to drill the word "FUCK" into this piece of cardboard.

I then shifted my attention to traces, and with that was able to make it burn the word "FUCK" into some wood.

I also burnt it into this adapter thing that seemed to be in the CNC router's box by mistake.

As for attempts at milling PCB material, they look rather miserable so far.

For scale, the three horizontal lines in the "2" shape above the "FUCK" are 0.1 inches apart.

At least part of the problem here was that my first attempt to cut into the material went too deep and too fast and so the cutting bit broke almost immediately. Rather than risk breaking another, I just continued on with that one for the rest of the testing. So possibly the PCB will look better once I get the process figured out but I figure I should learn as much as I can from the broken bit before I move on to another and possibly just break it too.

Here I was attempting to leave a row of squares of copper that aligned on 0.1 inch intervals, so they fit IC pins. It stopped cutting to the right due to the non-levelness of the PCB material. So I'm definitely going to have it map out the height of the PCB so that it can carve it all at a precise depth.

I kind of have my doubts at this point that the machine is really up to the task. In particular, trying to cut anything with a rotating needle tip just seems like a lost cause, making me wonder if some of the YouTube videos I saw might have been faked. ...but my 3D printer was a real pain in the ass to use at first too, until I learned how to use it properly, so for the moment I'm assuming this thing is just going to have a lot that I have to learn too before I can get good results with it.