This weekend I began drilling the holes in the ends of the plates. To do this I attached the right angle adapter to the mill. I struggled a bit with the best way to generate the gcode for the operations. I ended up simply coding it directly, since most of the standard functions of the mill are permuted with the right angle head on.
To align the plate with the table I used two 2-3-4 blocks and set up pins to ensure repeatability:
I made another quick video of the drilling operation. Sorry about the bad camera angle.
This allowed me to finally start assembling the plates together.
I also figured out a quick way of attaching the core to the outer frame to test fit the entire structure. This showed me a few issues I still need to work out, mainly around clearance for access to various screws and wire slots. But at least it's starting to actually look like a printer.