Originally Posted by
unworthy1
I'd suggest you opt for a different fix: find those U-shaped stamped metal slot-fillers that bolt into the dropout slot...anybody know what they're called? Much safer bet than trying to drill a straight hole the "hard way" thru a dropout, IMHO.
+1
This is what I would do. On bikes with no derailleur hangers on the frame the RD is bolted into what Unworthy is describing. You could take two of those(same size) and find something to bolt on the other side, like a thick washer, or similar.
Honestly I think drilling, no matter how carefully done, would weaken the frame significantly from heating as well as the existence of the hole.
Good luck! Be careful if you do decide to drill.