Help me with a Fidelity Research FR64 part

Ummm... Chak, I was just trying to be funny.  And I partially disagree with that definition of "thingamajig", having heard and used the term since the 1950s.  It refers to an object the correct term for which one either cannot recall at that moment or one does not know.  It's a useful shorthand that dates at least to WW2 military, if not before.  (I learned it from my WW2 veteran uncle when I was a very young child.)  I believe it to be American slang, but it could have emanated from England as well. I have never heard it used in reference to a person.
By the way, it's a "nut" in the sense that it is threaded and the use involves its capacity to fasten two things together.

Can I just say thanks for the efforts, links advice, and then intervention of Chakster!

My next point is this.

My machinist is actually very good, but the FR uses a 25TPI thread which is not standard, not only that but the base is something like 29.37mm diameter - 

 Based on my prior experience with re-tooling for Fidelity research and technics products, I guessed earlier that it is metric. 25 threads per inch is just about one thread per millimeter, which is a standard for metric. The thread pitch is 1.0. Of course, I am not there, and I am not a machinist. I don’t want to step on his toes.

Most of the machinists i have met are not interested to make just one small part, it is not interesting for them and they are busy with some serious orders. Unfortunately we're not their customes with one nut or one screw or anything like that (cheap parts).  

As I mentioned at the top of the thread (I think), I DO know a machinist who most likely would make this single nut for the OP, if he is given the correct specifications to work from.  That is Colby Lamb in Oregon, USA. I can provide contact info, if desired.  Colby made me a new threaded retaining ring for my SP10 MK3 platter; without that part it is impossible to fix the platter in place.  It sounds like the needed FR nut may be M30 (30mm diameter) with a metric pitch of 1.0.