I have found that trying to make threaded inserts consumes a lot of time and I'm not really set up for live threading so trying to do die threading has not worked so well either. What I do now is I buy 2" nylon bolts 1/2 inch by 13 and I turned the head down to.550" and then I bore tap the hole in the shaft and when cured, I drill bore tap for whatever I need. With shipping total cost per bolt is about just under $2 and nylon is pretty tough and creates a really nice firm feel especially on a 3/8 by 10 or radial pin.