SOG knives compared to SOG multitool knives

[Raukodur]

Went onto the SOG website and was watching their introduction flash movie and saw this pretty amazing frame.

I was wandering, is this just true for their most expensive and best knives, or more general? I.e. is this something to do with the steel used, or to do with the way they treat the steel (and so would apply to a wider range of their knives)?

And as the title suggests, how do the SOG multitool knives compare to their folding and fixed knife blades?

[Grant Lamontagne]

That's actually possible with almost any knife.  Soft, heated lead will split on any knife blade, despite what Hollywood likes to show us.  I don't know how much shooting you have done, but bullets tend to distort on impact with flesh and a knife blade is significantly harder than that.

As the story goes, I believe they shot that blade something like 177 times before they got the perfect picture.

As for the comparison, the tools use the same 440 blades that most tools have while the fixed and folding blades from SOG use more dedicated knife steels.  In addition I think SOG (and anyone else that makes both knives and tools) puts more effort into the actual design of the blade to increase cutting ability since that's all the knife does.  As a result, the multi blades usually won't cut as cleanly or keep edges as long as the knives will, but then the knives don't have the other features of the multitool.

Def

[Raukodur]

Yeah I understand the point about bullets being soft lead, but I would still think the kind of impact would break a knife blade.

I remember seeing this video a while back (maybe on youtube) where an experiment was being conducted on a katana. It was being shot at with some heavy duty, vehicle mounted automatic machine gun and did break, but then they showed exactly what was going on in slow motion, and the katana sliced quite a few bullets and took quite a lot of damage before eventually breaking. The point that struck me there is that when making a proper katana the metal is folding so many times, that much be why the blade took so many bullet impacts to break, whereas if it was a single piece of metal with no treatment, it would have broken much sooner.

Of course I do not know if that is the case.

Anyway, hmm, how have people found the SOG multitool knives in comparison to knives on other brand multitools (Vic, LM, Gerber etc.)?

[Grant Lamontagne]

The big difference between them is that the vehicle mounted machine gun was likely using metal jacketed military rounds, while the SOG was hit with good old fashioned lead.  There is little impact on the blade from the lead because of the softness of the lead and the very low surface area impacted.  If there was the same type of impact on the blade as there is on a regular target, then the bullet halves would have stopped when they hit the target or within a few inches.  As it is, with a minor change in direction, the halves in the picture probably continued on for quite a ways without having expended much force on the blade.

There's a fair bit of physics involved here, and I am certain someone much smarter than me could describe in greater detail.  However, the metal jacketed rounds would also be soft on impact, but harder than the lead rounds due to a higher melting point of copper.  Again, the same small surface area that allows a blade to cut better than a stick would also slice the thin metal jacket of a military round rather than break.  I am certain the breakage had more to do with metal fatigue than raw impact, the same way that a drop of water will eventually bore a hole in solid stone.

I'd lay dollars to donuts that if the machine gun had been loaded with lead (a bad idea due to heat build up) the katana would have outlasted the gun.

Of course one has to remember that the impact of a bullet isn't really all that great to begin with.  If it really hit hard enough to send bad guys flying through plate glass windows like it does in the movies, then the good guy would also have flown backwards from the recoil.  There's that whole law of physics that states something about equal and opposite reactions.  A bullet succeeds not by having a great impact, but by concentrating that impact into an area less than half a square inch.  It's not designed to meet a smaller target than itself, so is vulnerable to things like blades.  Not that I'd want to count on something like that in a real life situation, but I'm certain that SOG could have happily shot at that Tiger Shark day after day with no significant damage.  The edge would likely have to be serviced, and the finish would be shot (pardon the pun!) but the knife itself would likely not suffer any permanent damage.

Def

[ringzero]

Yeah I understand the point about bullets being soft lead, but I would still think the kind of impact would break a knife blade.

Try this experiment.

Set a lead bullet base down on a flat surface.  Caliber 45 would be good for this but a 38 will also work.  Semi-wadcutter or wadcutter would be best, but a standard round-nose lead will work if you are careful.

Grab an old beater knife with a sharp edge.  Press the knife edge firmly down on the nose of the bullet until it bites.  Now, increase the force on the knife to the maximum you feel comfortable applying.  Note how deeply the knife has penetrated into the lead.

Remove the knife and examine the edge.  It'll probably be dulled but not damaged.

This is essentially what happened in the SOG film, only it happened much faster in the film.

.

[Grant Lamontagne]

Plus the lead was softer....

Def