Well it seemed to stop, for whatever reason. Had some success today though. Finally made through 1 tool path without any troubles. I really need some compressed air though. The total toolpath was about 30min, and vacuuming chips for half an hour gets old. Still though, 3/8 aluminum plate is tough and not easy to go through especially with a $400 machine.
I ran out of good single flutes, so this was with a sharp dual flute. I like single flute more but it is far better than using a dull single. Tolerances check out, except for that estlcam doesn’t seem to have an oversize finish pass option, so the part comes out the exact dimensions in the CAD file. This is good and bad, just means I have to oversize on my dxf drawing.
Later tapped the holes M4, and did the M6 set screws that go along the sides.