[Ian, Daniel]

We lightly re-tapped (with what looks to be a plug tap) the problematic tapped hole in the 10" Vacuum Cube and discovered a bit of debris 1.6" deep in the problematic hole. The threads are not good before this debris, but this debris would interfere with a 1.75" screw. The holometer used 1.5" long screws for this flange. The debris looks like the end of a drill bit or tap; maybe the bad threads and this drill bit are related (someone broke this tip trying to fix the threads, or this tip was broken and therefore the tapping did not go deep enough.)

We tried to remove the debris with some tweezers and a pick, but it seemed to be stuck.

We then inserted a 1.5" screw with an external hex head and tightened it to 30 Nm. I will label this hole on the cube.