How old would this 15" swivel bolster be?

[Pile Driver]

Bolsters aren't magnetic, D stamped, slip spring, swedge blade, seemingly vintage horn, heavy lined, not many gaps

An 11" bobc and M.Italy stamped transnational in the background. Build quality on par with those
Thank you

[Folgore1]

wow thats really nice , with all features you stated i would date it around late 1960's up to late 70's . i got a 15" swedge blade made in 80's but the blade is not polished its a satin finish seems the polished blades were earlier like yours. the others you have in pic are nice as well

[Pile Driver]

Thank you sir, it has the feel of a vintage knife in hand

[Bill DeShivs]

These were made from the 1970s until the early 2000s with stainless bolsters.

[Folgore1]

these 15" stilettos were made by Angelo Campolin sr starting back in 1960's when he made the stamps to produce the parts to make the knives , the earlier knives he made had the slip-in type spring (as yours does) so i would say its one of the earlier models from 1960's , these 15 inchers were made with nickel/silver bolsters which are non-magnetic , some were made with stainless bolsters and some were made with brass bolsters. when me and Angelo re-made these back in 2005 we made them just like originals from 1960's the only difference was the 1 piece spring/backspring where as the older ones had 2 piece slip in type springs. you have a beautiful knife with awesome looking horn handles thanks for sharing with us

[Pile Driver]

Thank you for the knowledge , 1960s it is