[Ian, Daniel]

We tapped all 24 holes to secure the 10" flange on top of the Laser Filter Cavity (LFC) Input Vacuum Cube with the cleaned 5/16"-24 taps using some isopropanol as a lubricant. I used a 7 mm 12-point wrench. While its ~3" length made me apply more force to tap, I felt like it reduced the change of breaking a tap. We kept a 10" flange on top so that the vacuum system wasn't exposed. The taps fit within the holes of the flange. Before tapping, screws could only get 3 turns in by hand before encountering a lot of resistance. We used the tappered tap, plug tap, and bottom tap, going all the way to the bottom. The tappered tap went up 14 revolutions and the bottom tap went up 17 revolutions after tapping. The 1.75" long screws easily went into the holes after the plug tap and bottom tap. We used the bottom tap to ensure the screws wouldn't encounter any resistance when the flange is tightened. Some metal chips were generated. Some came out with the taps, some are surely in the bottom of the holes.

The TiCN coating might have been slightly removed by the end of tapping. The color might be different and the tapping may have gotten harder, but this is somewhat subjective.