The 3/8x8 ball screw is the Asian version of the Radial joint screw. Threads are close but not the same.
Schmelke was offering them a while back. They also offered the tap.
Then there's Mr. Wes Hunter Cues which I believe uses a 3/8x8 acme.
And in History, standard V pitched screw, there was Mr. Harvey Martin who later switched to a 3/8x10.