Hi Tankcmdr, and welcome to the forum again! The thread is as follows
.710 X 20 TPI at 55 degree...…. AND NO! you can't use 60 degree tooling, it will stop about 1/2 of the way, and sometimes stop forever! ...

.....How do I know this you might ask? Very stubborn people like me just cannot resist the temptation? Therefore, I come by the experience honestly... so, again, 55 degree, no more no less.... Best to you, til...lat'r...GT