I am guessing a broken tap puller is not an option?
Over the past 30 years, I have seen more broken tap extractors than I have seen broken taps
that had been successfully removed by a broken tap extractor.
They will work on something larger than a 5/8" tap but that is far beyond the scale of hobby machining.
A machinist's job is to fix things.
Even if the the thing to be fixed was their fault.
:hDe:
It's a never say die venture.
If all methods of removing a broken tap fail, there are still options.
Get a cheap carbide drill or broken carbide end mill ground to a chisel point and drill the broken tap out.
Then drill the hole to a size that can be tapped to a standard thread and tap it.
Find a piece of material that is the same as the parent material and thread it to fit the tapped hole.
A little LockTite, thread it in, mill it flat to the original surface and try it again.
There are a lot of heavy machinery parts in use today with those repairs in them.
Some of them have letter/number code stamped next to them that would identify me personally as
being the machinist who did it.
I like being
just a hobby machinist now!
Rick