If you need accuracy of removal, probably the best bet is spark erosion, at a cost £££. The difficulty will be drilling in the centre of the broken part.
Automatic centre punch? Several hits.
Depends how flat or otherwise the break is.
@JurekB started
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If you need accuracy of removal, probably the best bet is spark erosion, at a cost £££.
The difficulty will be drilling in the centre of the broken part.