The split crew continued.

Randy and Zack replaced the conflat on the dome according to M1000355. Kyle, please note for the record that the conflat has been tagged for later inspection. Later in the day, they worked on tooling (aka air drills).

Mark, Chris, Scott H. worked in/around chamber with Carolyn as recorder. Thirty sections were brushed which means that only half of the lower chamber body remains "dirty". Air drills again failed at a rate of ~50%. Bubba and I spent some time looking at a couple drills that had the crew worried because of black residue on the teeth of the chuck (although the metal shroud was clean). Zack disassembled the two drills in question so that we could look at the guts and see what was going on. After examination, Bubba and I agreed that the residue was not likely to have come from the interior of the drill. (The most likely source seems to be particulate that is pulled past the chuck by the vacuum. There is also some possibility that the chuck key could be leaving residue behind when it is used to tighten the brush in place.) I asked Zack to use chuck replacements on any drills that are rebuilt from here on out so that we can keep an eye on the situation.