So it turns out I was retarded, and all you have to do is drill a hole
and screw it in. No tapping required. I added some epoxy for good
measure, some in the hole and then coating the bolt. I screwed it in
and took the extra epoxy that seaped out and smoothed it around the
hole and bolt because it looks cool and was easier than wiping it off.

The failed attempt in the finger hole came out no problem, and there
was no real trouble cleaning the non-set epoxy out,just a mess. I was
even able to reuse the bolt.

I am going to find a leather strap to make the shackle out of so it
will be more comfortable.

Also, if you ever do this and are drilling by hand, start with a small
drill bit and build up to a bit that is a smidge smaller than the
actual bolt diameter. The unsteadyness of hand drilling into a round
object caused the drill to oscilate enough to mill the hole out to the
actual bolt diameter. My actual 1/2 inch drill bit made a hole too
big for my 1/2 inch bolt, had to drill twice.

Thanks for the advice.