Ball Bearing pivots actually weaker than PB washers?

I'm not qualified , either . But , wheels can turn corners . Bumblebees can fly . The very expensive Russian maker probably knows something we don't .

 

The very expensive Russian maker knows that a lot of people have excess money that the maker would like to take from them.

Coming next; differential bearings for those worried about scuff.

 

Pretty logical for someone who is not an expert. IF you look at typical thrust bearings you will see the outside diameter is a bit bigger to compensate for exactly what you are talking about. Problem is that you cannot do that for totally flat bearing. It would make the assembly to thick. With knives it isn't a big deal because the rotation is minimal. 180 degree rotation max.

 

Either the inner side of the roller rod will skip by "braking", or the outer side will skip by "accelerating". Possibly a bit of both all the way through. There is no rubber here to take up the slack, so it definitely is pure friction that will take over, at least in a part of the roller...

I guess the rollers (for a flat-type pivot) should be split in 2-3 short portions, as long one-piece rollers don't make a whole lot of sense, friction-wear wise...

Gaston

 

I can easily imagine some huge honking thick tank knife equipped with THRUST bearings . Even sounds cool !

 

Nope, simple physics

The further out from the center of a rotating circle the greater the distance travelled for a given degree of rotation

 

My concern with bearings is the open windows for grit that comes along with the prospect of a folding pocket knife.

 

Well, I scientifically cut open some boxes containing scientific equipment with the ZT 0561.
The bearings did not fail while cutting the tape.

You cannot beat data of that magnitude!

 

Can't bearings be sealed ? They should be for dirty work .

 

Yes, but it would make a knife unworkably thick. Think of a skateboards bearings which are sealed cartridges and they are at least 1/4" thick. That would make for a very thick knife.

 

There's probably a way to scale down that thickness some ? Anyway somebody must buy those tank knives . Medford and such .

 

Open spaces let stuff in.... and out. Look at glocks.

 

My 909 has been dropped in mud, kept in a pocket that constantly fills with dirt, and denied oil for weeks at a time.

Never an issue with the bearings locking up. I might give the pivot a rinse if it gets caked, but the 909 works regardless.

 

Not having made a study, I don't know. Not having used a roller bearing knife, I don't even have an opinion. But the question was "which is stronger?".

I don't have an answer but I am curious what the answer is. Unlike some folks here, I don't know or pretend to know everything.

See? That's what I said. Nobody is even trying to answer the question but all kinds of verbal gymnastics are being presented just to avoid an actual answer.

I'm guessing nobody wants to know the answer.

I'm out.

 

How the hell can we decide an answer with out actually conducting tests to know which is stronger?

Extreme side loads will likely cause damage to a washer, they are not crush or deformation proof. Hell I don't know, the answer is a usual.. it depends lol

Even if a washer is crushed or damaged the knife will likely still function, same as if the bearings indent the titanium the knife is still functional.

I see the Philippines is getting hammered with a storm on the news. Hope you and yours are well.

 

I guess that's the bottom line. I'm still curious though.

Another question for that is which of them will fail sooner with the same amount of damage.

Yes, it was headed our way but luckily we dodged the bullet when the track changed almost at the last moment. The storm killed around 100 people at last count.

 

I'm curious too, I have both washer and bearing knives. But I'm not going to destroy one of my bearing or washer knives for this thread. So, opinions will have to do

Good to here it changed course, I'm from Florida and grew up with hurricanes. The news/weather people can predict the path to an extent but big storms are unpredictable.

I've seen first hand what a roof ripped off is like.

 

This sound most plausible to me . So my "simple" WAG answer to the OP = YES !

 

Correct me if I'm wrong but I thought the whole point of bearings or washers in a knife is for smoother opening. I can see how it can be a weak point in a knife design. I feel as though the blade would break before a washer/bearing fails.

 

I don't know that ball bearing pivots are weaker. But I do know that they are strong enough to handle the things a properly used folder will encounter.