I did it. Tried using a stud extractor on an exhaust stud and it twisted off. OK on to plan B and cut it off flat, drill into and and use an easy out screw extractor. Snapped it off real easy up inside the hole... In panic mode thinking I would have to pull the cylinder I went google searching for Plan C.

Plan C turned out to be a tool called Rescue Bit. I am not affiliated in any way but I can report that this tool allowed me to turn that easy out into dust and I may have been able to use existing threads as I did not have to open up the hole too large. I chose to drill it out to 17/64 and install a Heli Coil to make sure everything worked out.

Thought I would post here in case any one else has the same misfortune. It was a difficult task to slowly grind that thing out of the hole using my dremel tool but it was sure better than any other alternatives I could think of.

This was on my 57 C-182 w 0-470L

Good to know! Few feelings are worse than an easy-out or drill bit that goes snap. Helicoil or timesert is a great lifesaver.

Way to stay calm. What's special about the rescue bit that keeps the threads intact?

Did you heat the cylinder head around the area of the stud with a propane torch prior to trying the ez out?

Looks a lot like some carbide bits I've used for the same application. Congrats on getting it fixed!

If it was your 470 most should have rosan locking studs. Safety wise I prefer to take off the cylinder and send it out to an engine shop to be chucked up in a milling machine to remove and replace broken studs. It costs but for me its worth it for the Rosans.

This was on an 0470 and I knew I was facing removal of the cylinder if that crazy bit had not worked. But it did, and it worked well. I was able to position my dremel to get very near straight in vertical at the broken easy out.

The bit is some kind of super hard material. I had to cut one in half and it ate up two dremel cut off wheel before I gave up and broke it in half. It requires using very light pressure and keep the bit from grabbing so it needs a little movement to keep it with room to do it's thing. When I was done I think I could have drilled out the remaining stud and then re tapped back to original size as I was very careful to avoid enlarging the hole. In the end I felt better going up and size and installing a heli coil.

I had no idea there was an option like this out there so thought I would pass it on here in case someone does what I did...