Metal drill bits and drilling out snapped exhaust bolts ...

[Gixxer 4 ever]

Also make sure you drill in the centre. Centre punch the work. Hard to us an easy out if it is not in the middle of the work.

[classic zed]

especially if you have broken a drill or ez-out in the stud, is to put a slightly bigger nut over the end and using a mig welder, weld the stud to the inside of the nut, let it cool a bit, then put a socket on it and undo it. Very often the heat generated in the welding process helps to loosen the stud.

If the stud is broken below the surface, before you try to remove it drill out the top couple of threads as these will be damaged and will most likely cause the stud to lock again.

[scumdog]

And when you DO get the ferkers out and replace them - use a smear of some anti-sieze compound (Kopper-Kote etc) on the threads before screwing them in, it will save you from having to undergo the same exercise at a later date when you want to take the zorst off again.