[AT] EDM (Electrical Discharge Machining) Drilling on old tractor steel and iron.

[Stephen Offiler]

I've had spotty luck with tap extractors.  Down around 1/4-20 and under,
they can be too flimsy if the tap is jammed (it broke, didn't it?).  And
you're screwed, pun intended, with spiral-flute taps.  But they can work,
with a little luck and patience.  I have also had some luck with "heat &
beat" (using a center punch to break the tap into smaller pieces which, you
hope, can be worked out individually)

Brad, if your stainless jobs are giving you trouble, it's probably due to
the tendency for stainless to work-harden.  It can be mitigated with
adjustment to speeds & feeds, and certain cutting fluids and certain tap
coatings (if not carbide) are more appropriate for stainless.

Steve O.
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