It seems only fitting that after breaking all those CNC bits that I should break-off a brass screw when mounting the first bracket, even after drilling a pilot hole. I drilled-out the bulk of the stub, so it should be fine. I ordered some silicone bronze screws that are stronger and will semi-match the bracket color. While I'm waiting for the new screws to arrive, I used some steel screws for the test fit.
The pivot holes in the arms need to be enlarged to 3/8". I drilled a 3/8" hole in a scrap of ply to center over the existing holes in the arms. This centers the 3/8" forstner bit for re-drilling the holes by hand.
With the pivot holes re-drilled, I could mount the new hardware to check the fit.
