Hi, I need some help that only american or english people can give me (I believe).

I'd like to know what kind of thread size is the female hole that holds the
compendium screw in my old/new Omega View 45C camera (that I believe to be the
same as Toyo 45C). I am italian, and here in Italy it is hard to find the way to
"measure" such a little female thread - we use almost exclusively metric screws.
The question is in order to try to adapt the ShenHao compendium that still I
have to the old Omega LF camera that I have recently bought from USA.

I am sure it is NOT UNC 8-32 (but very similar), and that it is not metric.

Can someone help me please?