I have just broken a recently new 2-56 tap off in a 3/8 inch deep hole in 7075 aluminum. Has any one ever made a hollow hole saw to try and render out the offending tap piece? I thought of trying drill rod to make the cutter then harden it. Kind of like a small hole saw, then tap the hole for a plug of metal and re-do the 2-56 threads. I don't have a lot to work with except time. Any thoughts?