[gofastwclass]

A solution to removing rounded off or broken bolts and studs is using a TIG welder to weld a nub to it you can grab with a pair of vice grips.

Another option is to weld a nut to the broken off bolt or stud with either a TIG or MIG welder then remove the offending remains with the appropriate socket or wrench.

This works best in aluminum, but can be done on steel and cast iron if you are accurate enough. Using a TIG welder for either of method is ideal due to the accuracy, but a MIG will work too if that is all you have in your arsenal.