Oversized pivots: Pros and Cons?

[singularity35]

It is for looks: blade will break first!

Proof of that?

 

[Poez]

Proof of that?

I am not really ready to break a knife to prove the point. But I have not heard about broken pivots in any destruction tests that I have read about or seen: it was always the blade or the lock. Have you heard about pivot failing first? I am not challenging, just curious.

 

[Bill1170]

Like Poez, I have no proof but the anecdotal reports here on BF about broken folders always seem to be blades and locks, with a rare stop pin incident or two. I have never read about a folder that failed at the pivot. Maybe someone who reads this thread can report an instance of this happening.

 

[singularity35]

I am not really ready to break a knife to prove the point. But I have not heard about broken pivots in any destruction tests that I have read about or seen: it was always the blade or the lock. Have you heard about pivot failing first? I am not challenging, just curious.

You should probably qualified your statement with an "IMO". Which destruction tests are you referring to? I haven't seen any of those where the blade broke, and in fact, I also haven't seen any destruction tests on hard use knives with oversize pivots. Also hard use knives with oversized pivots usually have thick blades.

Like Poez, I have no proof but the anecdotal reports here on BF about broken folders always seem to be blades and locks, with a rare stop pin incident or two. I have never read about a folder that failed at the pivot. Maybe someone who reads this thread can report an instance of this happening.

I'm saying that when faced with the OP's question, we have to look at the particular knife and task before we say automatically "blade will break first".

Take this vid for instance, don't you think the ZT 301's pivot size had a factor in keeping the knife together? Say compared to the pivot on an endura.

[youtube]Kyl2CGb2N38[/youtube]

 

[twid]

^ hey, it's me

Just want to mention that the ZT30X pivot is really not that big, it's just solid rather than a Chicago screw that's close to the same diameter except hallow. I believe a solid bolt will always be stronger than a hallow screw i.e. about every other pivot out there including Strider and Umnumzaan's large pivot. The larger heads provide more clamping area perhaps making it more rigid side to side than say a Delica but in any scenario imaginable the blade, liners, or locking mechanism would fail before the pivot on either knife. If you've ever kicked out a door it's either the lock, screws, jamb, or door itself that takes the damage while the hinges (pivot) are still intact (hinge/pin/hinge).
The only way I could see a pivot causing failure is if the screws got loose causing the blade to be used out of spec with the lock. That would be an engineering or maintenance failure.

 

[tirod3]

Cheap swuss army copies fail at the pivot, the design is basically a bunch of brass pins pressed into holes. In the day, the bone and brass old school stuff could eventually fail, but the user would likely break the tip off first. Hence "the blade will break before the pivot."

Looking back on knives used since the '50s, it's more than a "IMO" or anecdotal view.

The reason is that very few pocket knives use differential heat treating to make the edge hard but leave the blade back softer. Most are heat treated whole in the ovens by the thousands, and if there is lock back, it gets thrown in, too. Many companies didn't temper them spring soft, one reason issue military knives like the Camillus would break back springs. Very common to find them in gun show cases like that, the springs were tempered too hard.

Huge pivots are basically tactical decoration - normal ones put up with everyday abuse for years, making them 400% bigger is really just for looks. When the "beat me and make me bleed" uber folders started coming out twenty years ago, the makers chose massive pivots to make their knives look the part. When spine whacking started soon after, the majority of results were failed locks for either type - not pivots.

Those of us using them since before the invention of the internet or youtube learned it without needing somebody's unscientific video of how cool they are.

 

[bld522]

Ah yes. There's just nothing like the voice of experience, is there? :thumbup:

Anything I do to a knife that gives me reason to think I might break it . . . regardless of where that break might occur . . . is a sure sign that I'm using the wrong tool. Granted, some knives break that should be able to take the level of abuse I place on them. But I'd be willing to bet dollars to donuts that a far greater percentage of knives break because they're asked to do something they're not designed to do.

 

[jstn]

Cheap swuss army copies fail at the pivot, the design is basically a bunch of brass pins pressed into holes. In the day, the bone and brass old school stuff could eventually fail, but the user would likely break the tip off first. Hence "the blade will break before the pivot."

Looking back on knives used since the '50s, it's more than a "IMO" or anecdotal view.

The reason is that very few pocket knives use differential heat treating to make the edge hard but leave the blade back softer. Most are heat treated whole in the ovens by the thousands, and if there is lock back, it gets thrown in, too. Many companies didn't temper them spring soft, one reason issue military knives like the Camillus would break back springs. Very common to find them in gun show cases like that, the springs were tempered too hard.

Huge pivots are basically tactical decoration - normal ones put up with everyday abuse for years, making them 400% bigger is really just for looks. When the "beat me and make me bleed" uber folders started coming out twenty years ago, the makers chose massive pivots to make their knives look the part. When spine whacking started soon after, the majority of results were failed locks for either type - not pivots.

Those of us using them since before the invention of the internet or youtube learned it without needing somebody's unscientific video of how cool they are.

Thanks for the seasoned response tirod3. I wouldn't really worry about breaking a pivot since I don't use my folders too hard, but would it make sense that a larger pivot diameter would reduce blade play? Some knives I have to tighten the pivot down all the way the eliminate play, but the knife becomes more difficult to open/close. It seems a larger pivot might help with this issue?

 

[MrGlockJock25]

Spyderco Tuff has a pretty big pivot I would say.

 

[Poez]

Spyderco Endura.
Looks ridiculous? Works for me!

 

[Sword and Shield]

I don't see fat pivots affecting friction very much either way. A folding knife is only as strong as its weakest component, and that weak link is almost never the pivot. I also see very little downside to a larger pivot, within reason. Make it too huge and other parts will have to get bigger just to accommodate the pivot.

Ditto. I've never seen a folder fail at the pivot. Scales at the pivot, yes, but the pivot stands. This includes a large number of older slipjoints that have seen more work than most ever will.

 

[Ianmorrow21]

I think that the pivot should be matched to the blade stock. I.e. Strider's have a huge pivot with good reason. Like others have said, I can't think of any pivot failure stories off the top of my head, or even on Youtube. I think that if you somehow manage to break the pivot on your folding knife, you were likely not using it as it was intended to be used.

 

[ThePeacent]

Maybe it's oversized, but in relation to the knife's size...

Everything is relatve!

I personally love big, flat pivots, so the reason is mainly aesthetics for me.

 

[RX-79G]

The most likely thing to break on a knife is the hardened blade, not the pivot. Drilling a bigger hole in that blade seems like a weakness, not strength.