Originally Posted by
shoota
The truth is probably somewhere in the middle. I wouldn't be at all surprised if it creates a stress riser in some stems, that will eventually crack.
I'm somebody who has "done it all day" and never had a stem fail due to that hole and countersink drilled.
So I surmise (and have not had UL testing done) that there is very little critical stress in that part of a typical quill stem, that gives rise to any real and present danger...stress riser or not.
But...YMMV