Easy job

[awemawson]

Pop them out using a Diesinking EDM machine like this one.

Slow but certain - I've just been using it to pop 6 mm tommy bar holes through a socket set for a friend

 

[doubleboost]

Not sure what I'm looking at, look like a steel dowel/rivet pressed in Al casting which someone has tried to drill (poorly)....I'd have a go at pressing it out first.

they are 10 mill bolts in a fully threaded hole

 

[Shox Dr]

they are 10 mill bolts in a fully threaded hole

thats a bendy drill

 

[Robert.]

I have on occasions used the plasma cutter for extracting sheared hardened bolts or ones with a fitters drill or easy out snapped off in it that ain't too deep . Grind both sides as flush as possible . Line her up , shoot a hole straight through then carefully work to the outside . Once you have most of it cut out , just collapse the rest and pick it out .

 

[doubleboost]

I have on occasions used the plasma cutter for extracting sheared hardened bolts or ones with a fitters drill or easy out snapped off in it that ain't too deep . Grind both sides as flush as possible . Line her up , shoot a hole straight through then carefully work to the outside . Once you have most of it cut out , just collapse the rest and pick it out .

Even real heat would not release them Did a bit video for Sunday

 

[Dcal]

Nice job.
At least the heat will take the temper out of them.