I know there are some really smart turners here and I'm hopeful that someone can help me with this issue.
I have a Oneway 1640 lathe.
I also have a Oneway live center that I use constantly.
I would like to find a way to make accurate parts that fit onto the thread of the live center.
Currently I am making lots of sphere and would like to make (read "not buy") a cup center for the live center.
Because the Live center has a #3 Morse taper and my headstock has a #2 morse taper I can't just put it in the spindle.
The cup center I have made was made from a plastic I'm not sure what but machines really easily but tends to make very very long pieces of plastic that wrap around everything. I cut it from a large piece. Turned it between centers put a shoulder on it, drilled it for a 3/4" tap. Reversed it in a chuck that held the new shoulder and made a cup. It just won't run true once I thread it onto the live center and as a result I can't do a very good job of removing the nubs I leave on the spheres I make.
I was thinking that if I could find a nice 3/4" machined bolt I could cut the head off of it and then mount it in a collet chuck and thread my piece on (would I need a shoulder for it to tighten agains?) then turn the cup but I think I need a nice tight thread and most bolts I can find are a rather loose thread.

Any suggestions?