Drill a pilot hole the same (or slightly larger) than the diamter of
the final dril bit that is not fluted. If your final bit is large,
this may take a couple of passes with different bits, each employing the
same strategy.
Calvin Krug wrote:
>
> I'm hoping one of you mechanical-types can help me out. I recently had a
> steel exhaust manifold flange welded, and now I'm trying to redrill the
> hole for the stud. I can't find any drill bits that will cut through the
> welded steel. I've tried regular high speed drill bits, titanium-coated,
> cobalt, and most of them won't even touch it. Yes, I'm using cutting oil.
> I've managed to get about 1/8" through, but the more I try, the less effect
> I seem to have. Any ideas?
>
> Calvin Krug
> trying to rebuild my MGB
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