L/W, I'm sure you're right about the end-grain weakness.
Splint, you offered up a lot of useful suggestions in a short comment. I'll file that away for future reference. I did look only in the hardware aisle. Maybe I would have found something in the plumbing aisle. I never considered a hole saw; I didn't even know you could buy them as small as 5/8" (or I guess 3/4" for a 5/8" OD hole). Your method would have been much faster.