Is this the same topic or a new one...?
Boy, all this surgery sounds like the prelude for "Damaged Carburetor" which will be followed by the sequel called "Need a New Carburetor".
How much you wanna bet, that when you drilled into the mixture screw with a drill bit that was turning
clockwise that you also turned (tightened) the mixture screw all the way into the screw seat...(that will sometimes break the tip off the mixture screw, and ruin the orifice).
But then you beat on the screw with a screwdriver and a hammer while trying to make a slot? Say what? Were you trying to make sure that it was jammed all the way in? If nothing else, the hammering most likely mushroomed the brass end inside the hole...or screwed up the threads. After all, the carb body is cast aluminum and the screw is brass, plus there is even a seal in there too.
Whatever you do, don't try a screw extractor. You might drill through the carb
Sorry man. not trying to give you hell, but that was just a cluster fluck of things to do.
Back to the problem...I think that I remember someone else that had to get a screw out. As I recall, he used a dremel tool and cut away the aluminum on the front side of the carb around the mixture screw. Then when he got down to the top of the screw, he was able to turn it from the side.
I'd try that if you can, but I bet you might need to take it to a shop.