I was making some small parts that when reversed in the 5C collet to work on the backside weren’t sitting correctly.
you can buy ready made versions from Arc et al for approx £10 but I thought I would gave a go at making one.
The thread is 1.05”x 24 tpi, I cut it to the same depth as 3/8 UNF and it fits nicely.
the rod is 2BA which was the only all-thread I had lying about, I may change to a beefier size in due course.

