Richard J Kinch wrote in message ...
Bob writes:

Any other methods of doing this that I have overlooked, I already
tried google.

Drill and tap for 1/2"-13 threads and just screw it in. Get the tool at
Home Depot or an auto parts store. A washer and jam nut at the top would
prevent hand untightening but readily disassemble with tools. Rather
important for a safe restraint, you know.

This did cross my mind, but I do not have the tools. I might be able
to get access to a drill press. Even if I did drill it by hand or
not, how difficult is it to tap it? Can you tap the material inside a
bowling ball? How deep could I get the threads to go? Is a tap of
this kind expensive?