I figure if it doesn't have an electronic part on/in it then it could be considered vintage. I have a mid 90's Bernette that would be considered old by today's standards but it is purely a mechanical machine. Compared to that a thats a late 90's plastic Husqvarna i recently acquired. They seem to be from two different era only because of the components So I guess all mechanical machines up until the mid eighties. The only reason why i bought these 90's era machines is because I will never be able to afford a brand new Bernina. LOL and I needed a lighter easy to transport machine like the the Husqvarna for classes and such. Of course both were under my $30 price point. The Husqvarna was $10. *wink*
My main interest in machines seems to be from the 1940's to 1960's and some 1970 Kenmores.