This may not be new to some, but I discovered it today on my own and
it may help you in a pinch.
I had to get three pieces out that were not finished. Needed to
drill a bale hole in the pendant which was 3/8" thick or better.
First two went fine. Started small and progressively got larger bits
until I had enough for a 12 gauge wire. Large heavy shark tooth. The
third one I broke the bit. And it was way in there. I spent an hour
burning up bits trying to go around it and through it. I tried poking
it, banging it on the bench block, super magnet. Even cussing did not
help. I drilled the opposite side where I thought it would come
through. Used a ball bur to open it a little. Then took a Starret
drill punch and punched the opposite side. (For those that do not
know, these are spring loaded and exert a good amount of energy
force to give you a divot where to begin drilling.) Nothing. Out of
frustration as I knew I was going to scrap it, I punched it two or
three times and then another as I was so po’d. I turned it over and
there was the end of the drill bit poking out from whence it came. I
tried grabbing it with tiny needle nose to no avail. Two more punches
and the energy forced it out into the scrap drawer.
It may or may not work for you. I hope to never try it again!