In article pdTie.9662$E05.5496@trndny09, oparr says...

Long story short....Not an issue provided the center drill has an
unobstructed path to the flat.

Actually no.

Doesn't matter even if it *does* have a faced surface to
start the C-drill on. The twist drill that picks up that
centerdrill will make some kind of hole that cannot be
guaranteed to be better than a few thou within center.

If it's off by five thou, your reamed hole will be
off by five thou.

Have you considered the tolerance you need for the
application?

Jim


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