On 7/18/2015 9:15 AM, Mark628CA wrote:

It may be obvious to most people, but do
not drill through the trailer side without taking your wing out first.

Ha ha ha! Years ago I was drilling out rivets on both sides of an HP-14
aileron rib. All went as planned until on the second side near the trailing
edge. When the drill broke through it happened to be perfectly aligned with
the rivet hole on the (nearby) opposite side, a possibility I hadn't
considered. I still have the scar in the palm of my other hand from the chunk
of muscle and tissue that was attached to the drill bit upon extraction. At
least the sheet metal holes ended up round and not oversize...

Bob W.