Stripped threads on upper control arm ball joint socket

I agree with tacking them. Do not overheat. New ball joints have plastic ups.
Who is reproducing them? Where can you get them?
I got uppers from Amazon for my 72 Scamp, no problem. But lowers were a different story. Left side lower I got from Amazon but they were outa stock for the right side. So, I ordered from Rockauto and they sent me the wrong right side lower twice. They were real good about sending me a refund after that. Anyhow, after waisting about a month with that, the right side lower was back in stock on Amazon so I got that and the car is a way different animal with all new ball joints in it.