All, thank you so much for the promt responses.
This yahoo email address is the one I've used, though no answer yet.
Anyway, what I am looking for is a "Nut and Bolt" set in 48th scale (#106) obtained from Copper State ages ago. Unfortunatelly I cannot find any stock of it (already tried the Copper State Models and even Aeroclub, who both I thank for their kind responses).
Taking a look at an old Fotocut brochure I found out that Fred had something similar on production.
Ok someone may say, why don't you take a Punch 'n Die set. Well, I cannot find any tool that can give me a hex shaped nut with an ext dia of 0.4mm, more over this type of PhotoEtched set had a vinyl carrier and not a fret requiring scissors cutting and filling.
Any ideas of where I can find or even custom made something like that?
Best wishes
P