"Jeff Wisnia" wrote in message
...


Methinks that EDM may be the "way to bet" on that one.


EDM? You must have deep pockets. I've drilled through taps and reamers with
carbide endmills.

Having a geared power feed is really nice but possibly not necessary.

OP should consider GRT-series carbide tipped masonry drills from Relton
(www.relton.com for resellers). Drill's packaging specifically states the
drill can go through hardened metal. Special tip geometry and carbide grade.
Typically 1/3 extra $$$ for GRT as opposed to standard masonry bit.

Regards,

Robin