FWIW, I cobbled together with washers and a 5/16"-24 bolt something that will hold the tool in place. That was all that was available on a Sunday and was the best fit even among the metric stuff at Lowe's. It will go in a couple of threads and it doesn't really doesn't take much force - mostly functions as another set of hands.

With a 12" wrench I still can't get the darn thing off. I could probably force it with a sledge hammer but given the cobbled up contraption holding the tool in place, I'm not comfortable with that. And I don't have a breaker bar that I can fit over the wrench. And I don't live in a 'decent sized city'. So I'm off tomorrow to (probably) get a breaker bar and the right bolt (about 45 miles away).

Thanks again for the great help (even though I have failed so far). And this has gone a LONG way toward dampening my (possibly ill-advised) intent to get good at real bicycle mechanics :-)

dave