JDW,
I usually just do it this way when I don't have a die around for the thread size I want or want a better fit.

When I single point, I set a 2 or 3 inch travel dial indicator on the bed and dial out and drop out the carriage leadscrew at a predetermined point. I've gotten pretty good at this over the years and can usually singlepoint a thread in less time than it takes to go buy a die. When you have good equipment and familiarity, it can go really fast.