Hello
I do not know if I will give myself to understand, because English is not my language
I think the first thing you should do is know how big the missing screw is. I mean that you must find out the diameter and pitch of the screw, checking the threaded part of the holes in the lock Example [: 5 mm metric screw. by a step of 0.8mm.)
As at that time the diameters and steps were not standardized, it is a bit difficult to get a copy, but it would be necessary to try with numerous screws (metric or Withwort) until obtaining one that threads. Knowing this, it is easy for a turner to modify an existing screw, or to manufacture one from scratch, modifying the hexagonal head to round, according to the surviving example.
Affectionately
|