[Jeff, Daniel]

We placed a 10" blank flange on the Input Laser Filter Cavity (LFC) Vacuum Cube North End and tightened the screws to 34 Nm. We moved 10" flange with electronics D-Subs to the Demonstrator Interferometer Vacuum Cube (transmitted arm) so that we can lock the interferometer with a piezo. I tightened the screws to 13.6 Nm with one pass but decided to go home and not work alone. These flanges and faces on the cubes were a bit dirty, so we did some cleaning with the wipes meant to clean inside vacuum chambers. We moved the 10" to 4.5" zero length reducer flange to the top of the Input LFC Vacuum Cube, but the screws did not want to go in more than ~0.35" before almost all of them had a lot of resistance. The holes seem tapped and deep enough; I measured 1.8" from the top of the flange to the bottom of the hole. I think we need to re-tap or clean up these threads. Ian recommended getting a thread chaser kit. I think this one would be a good option. We placed foil on the newly exposed face on the Input LFC Vacuum Cube. I want to seal up the flanges before potentially making chips on top of the vacuum chamber.