What, please, is the issue or pattern designation of that USA Fighting Knife/Bayonet that has a Bowie type blade and at the rear of the handle has a distinctive six sided hexagonal "nut"? And roughly, please what are they worth to collectors?

A bayonet will have a ring for the rifle muzzle and a catch at the rear.
It is a USAF survival knife; probably a Marble, Camillus or Ontario; date from the 50s on; the hex pommel is a tool for an airplane canopy or something like that.
Value? $100-300 if mint. Plenty on eBay for $35 and up; new made ones are about $30.

DPCD thanks. That's everything I need to know. Now knowing what it is I've been able to check it out. I've looked also on internet eBay and the like here in UK. Knowing now what it is has helped greatly.

Thank you for replying. It makes sense in the 1950s and 1960s the local girls used to bus themselves to a local USAF base for socials and dances. So I can pretty much make the rest of the connection that it's maybe someone's gift to that girl or to a male member of her family. Thanks.

There's one in an local auction house, two miles from me, online estate sale here in UK that ends Monday at 9.00am. Currently it is at UK £20.00. Your input has been helpful as I know now that there isn't much margin left in the think for a re-sale and profit. And it has no sheath.

Thank you as now I know it isn't a Special Forces or Rangers more "desirable" (to buyers) item I know my bidding limit.

Good; 20 pounds would be a good price; I don't have that fancy pound symbol on my apple.

I got my pilots survival knife for the magnificent sum of $5 from a guy on my ship while we were making our Westpac cruise back in '66-'67. Sent it home so some fool wouldn't steal it.50 some odd years later I still have it. Frank

A lot of reproductions out there, something to consider.

Grizz