I carried an issue one of these for 13 years in my military service and whilst they are bulletproof (literally) the edge retention was always rubbish. Whenever you picked one up it didnt so much cut stuff as wear it away. The most useful thing was the can opener which worked a dream when the issue compo opener had given up the ghost. They are heavy and the screwdriver end wasnt hard so in any kind of hard screw it would buckle & twist out of shape. At the time i knew jack about heat treating steel an so never tried to harden & temper the thing and being stainless it would not be so eay but may prove worth a try.
Incidentally the phrase 'Jack knife' originally meant a sailers knife (as in Jack tar) specifically because it had a marlin spike for rope splicing. Its used to open the strands in a piece of tarred rope to begin an eye splice, which is a very strong loop at the end of a rope. Originally marlin spikes were exactly that - the nose spike from an atlantic marlin fish, which had the strength and resilience to force open the strands in a rope of 2-3" diameter, if you dont think this sounds like hard work, when navy ratings had to to this on a main brace they were issued an extra tot of rum - hence the expression 'splice the main brace' meaning to go for a drink.
Enough history
Cheers
Nick