Technical question (construction of the Walloon sword)
 

Dear colleagues,
I would be grateful for opinions on the following question: is this "nut" a separate element (threaded connection) or is it a riveted part of the tang?
I'm assessing the possibility of neatly detach the blade from the hilt.

PS certainly "design" not "construction" :)

I’m not an expert on this but typically I believe these 17thC swords have pommels with a button, on top of which the tang is peened. You should then see a round flattened sphere at the top of the button (not shown in photo). I hope a more expert member can confirm…

hey Evgeny_K, that's mostly riveted and not screwed. Screw connections did not appear until around the 19th

Here it is

Maybe if you use after removing rust and for a short period a weak acid like a drop of vinegar, it will etch the metal from the pommel differently from the metal from the tang and you will distinguish what is what.

Walloon Swords construction
 

Coming late to this, I have 9 C17th swords (all but one are English) and they all feature a tang 'bun' like this.