Not dug but Kinda odd, Ive never seen a Brass blade on a Knife B-4, has any one ever heard of this or why? It appears to be Hand made to me. Even the spring is Brass.
would love to find out more about it.
admin is correct, but these types of knives are sold on cable knife shows regularly, are probably chinese or pakistan now and don't sell for very much. Sometimes they are offered in the Smoky Mountain Knife Works catalog for $5-$7. Sorry...
I don't know the history of the knife, but I know enough about brass to know you can't harden it to make a spring out of it. Perhaps a brass-colored alloy? Beryllium Copper or something? Non-magnetic and at one point used by the military for knives.
I would like to point out that if you hammer harden brass and then avoid heating past 200 degrees Fahrenheit it will not only hold a good edge but in some case can even be comparable to steel in spring retension and tinsle strength