aluminum rib, aluminum spar, holes drilled but screws broken off

jls wrote:
I'm rebuilding a Super Cub wing and the flanges on the ribs and the


blahblahblah. Larry, you damn long-winded thing, you.

OK, guys, here's what the friendly engineer says. Use a 3/32 cobalt
drill bit. Drill at 28k rpm or better and use cutting oil, ie,
kerosene and lard. Hit it and back it off; hit it and back it off.

Will let you know how it works, although I bought a lot of that other
recommended stuff and a diamond burr the dentists use.