I used the plexiglass bit to drill 1/8 thru the holes in the aft skin.
It was a two step process for the roll bar holes. First I drilled the plexiglass at the ink mark indicated and I let the tip scribe the roll bar. Then I switched bits to the aluminum bit #40 and drilled the roll bar thru the 1/8 hole in the plexiglass. This worked fine. Later these holes in the roll bar get enlarged to #35 for threads.
