In article ,
Rusty Hinge 2 wrote:

Using my methods on iron pipes would require serious outlay on special
drill-bits, as cast-iron blunts even HSS very quickly.

I did have some stellite-tipped drill-bits which were quite good, but
you needed a bench-drill with a hefty press, as the idea of the stellite
tips was to soften the iron by friction, thus heating it close to its
melting-point, when it would begin to go through it like I go through
cheese.

And do not be tempted to use a hammer drill to speed things up,
on the grounds of preserving both your dental fillings and the pipe.


Regards,
Nick Maclaren.