There was a thread a while ago about threading a 5/16-18 to 5/16-14 in a wood joint. The guy who said it worked fine got a very negative reaction to his post. Anyway, I tried it on a shaft to see what would happen, knowing that if it did not work I would just put an insert into the shaft.
It has worked fine for more than a year now. The only problem that I have come across is that it some times locks together very tight and I need help to undo it. This is on the 18 tpi pin. The 14 tpi pin handle does not have the problem of the shaft locking on.
Neil