I was rotating the carbides on a wood planer and a couple of them were held in by machine screws that weren't budging. I called Byrd, and their recommendation once you've stripped the screws is to shatter the inserts. I put a crappy chisel underneath and whacked it with a hammer.
I can confirm that it works. I heartily recommend a face shield, and I wouldn't want to be the first guy the doctor had to break a ring off of.