Back in the early 90's Leonard used to have a wonderful bit of bullshit he would lay out about that pin. Claimed it was developed as a result of years of scientific testing and that it had "the most wetted surface" of any pin in the world.
The truth, however, is he had bought a large quantity of stainless thread rod at some auction (bankrupt shipyard?) and just cut his pins from that. I know 'cause he showed me this big stack of scrap rod and told me the whole story. The specs on that thread are 11 1/2 tpi, with a major diameter of 0.348" (after polishing) x minor diameter of ~ 0.285". Many metals lathes I've used, including all those in my shop, have a standard setting to cut 11.5 tp so you should have no trouble fabricating one for your refinishing purposes.
TW
(PS: FYI, I quit paying attention to anything any Bludworth did after the mid-90's, so there may have been a switch to a "real" joint pin some time thereafter.)