An unscientific poll about knife pivot bearing types.

[PURPLEDC]

Basically , most here states that did not have a problem with BB pivot .Well it s OK , I believe you . The fact that you have not had any problems does not mean you're right . Take one small OPEN ball bearing , degrease it , apply a drop of oil , spin it with hand and then throw it in the sand ! Next , if you turn it without cleaning I will buy you a knife at your choice!
You can try the same with washers ....................I can bet that washers will spin after sand

IKBS knives with no captured retainer. Just loose ball bearings. Me thinks you worry too much.


[video=youtube;dlBO72rHb64]https://www.youtube.com/watch?v=dlBO72rHb64[/video]

[video=youtube;KJWikio-EbI]https://www.youtube.com/watch?v=KJWikio-EbI[/video]

 

[blade man]

Either can be just fine. I've not had a pivot/washer/bearing failure with either type, but I have had washer knives get stiff and require a good cleaning to smooth things back out. Bearing knives tend to be so much slicker that to get to same level of stiffness takes much, much longer, usually longer than I would go between servicing a folder carried regularly.

 

[Therom]

The fact that you have not had any problems does not mean you're right .

#facepalm
So what is the point of sharing experiences if the only thing to oppose is hypothetical and just an unrealistic use of the tool????

I don't see the point of overthinking it

I respect your analysis, but IMHO it is not a point of being right or wrong.
As a fact it just seems that most people in standard conditions of use didn't faced more issues with BB than with washers
It is neither a theoretical nor a scientific demonstration, just a ROE

 

[Thomas Carey]

I have never had a failure of any pivot system other than knives with cheap nylon washers. I have those split but that was on cheap knives.

 

[Natlek]

#facepalm
So what is the point of sharing experiences if the only thing to oppose is hypothetical and just an unrealistic use of the tool????

I don't see the point of overthinking it

I respect your analysis, but IMHO it is not a point of being right or wrong.
As a fact it just seems that most people in standard conditions of use didn't faced more issues with BB than with washers
It is neither a theoretical nor a scientific demonstration, just a ROE

Sorry . I should have express myself like this ...................The fact that you have not had any problems does not mean that bearing are better solution from washers

 

[palonej]

And the fact that you 'think' bearings are the devil's work does not make it true.
Joe

 

[Therom]

I never meant that one is better than the other
So far for me both have just worked fine
As a consequence for me either is fine for my knives

 

[Max Archer]

I don't understand the implication that bearings are somehow the less reliable system. Coming from a motorsports background, I've always known solid bearings (in knife terms, these would be washers) as something used only in situations with active lubrication and/or when severe axial loads are expected, and they've very sensitive to foreign objects or debris. Roller or ball bearings, on the other hand, are more tolerant of dust and debris (as evidenced by their use in driveshafts and wheel bearings), they are not intended to be regularly replaced maintenance items, and they're ideal for situations where they're providing a smooth bearing surface for an object to rotate on and are not subject to heavy axial other loads. All of these features would indicate that a roller or ball bearing pivot is by far the superior mechanism for a knife pivot.

Washers certainly have a cost and complexity advantage, but bearings are technically superior. I know there have been knives where the bearings were problematic, but that's a case of poor engineering, not an inherent flaw with the mechanism.

 

[Aldebaran]

Actually Max Archer I think you have it backwards. Ball and roller bearings are commonly known as "anti-friction" bearings and their primary use is in non-static and not low speed loads. In a car engine the most commonly used bearings are plain bearings. The are on the crank shaft, the piston rods, and the camshafts. Why? A few reasons. First is that less parts means lower cost. Second, they stand up to the high loads they experience when the engine is just starting and there is very low speed involved. Lastly, they are extremely reliable and usually outlast the rest of the engine, even the whole car, if the engine is maintained properly. It is not unusual that the ball bearings in the wheels and the throw out bearing in the clutch to need replacing at least once in a car's lifetime. You are correct that they are less tolerant of contamination between the mating surfaces of the lubricant than ball bearings, but the contamination of a plain bearing depends on the spacing between the surfaces and the size of the particles. The movement of a washer type bearing in a knife pivot does not promote entrance of particles if adjusted correctly. I am not saying that washer pivots in knives cannot be contaminated, just that is not promoted. Dust will eventually creep in and require cleaning and re-lubricating.

Ball bearings are designed for high speed movement where the friction on the lubricating wedge of oil or grease becomes a real problem for plain bearings. They do not tolerate high loads at low speeds and they are highly de-rated for their load capacity at low speeds and when stationary. They also suffer point contact fatigue between the bearing and the rolling surface. This causes what is commonly referred to as Brinelling where the hardened surface overlying the softer subsurface deflects under load and fractures and the spalls away causing pits the surface. This quickly accelerates and becomes complete failure very quickly. Hard particles that contaminate the interface between the ball and the surface can start the process early and/or exacerbate the situation very quickly.If the contamination is softer than the surface of the ball and races, then it is easily displaced and hardly affects the performance of the bearing, except if it prevents the ball from rolling and makes it skid instead. In this case you start a rough surface which then quickly begins to spall. There is a reason that ball bearings are sealed from the environment in any design made for longevity. They will have shields or seals to prevent the entrance of contamination particles and to seal in the grease so that it cannot escape. Ball bearings are more forgiving of temporary loss of lubrication as they roll whereas the loss of lubrication in plain bearing usually leads to instant and permanent damage. A ball bearing without seals allows instant entrance of particles and instant contamination of the bearing. The material composition and the size of the particles will determine if they will cause failure or not but they get in without impediment.

A properly designed and lubricated plain bearing has a theoretical lifetime of forever. A ball or roller bearing has a limited theoretical lifetime regardless of how well maintained or lubricated. Each have their uses and benefits.

 

[Natlek]

I don't understand the implication that bearings are somehow the less reliable system. Coming from a motorsports background, I've always known solid bearings (in knife terms, these would be washers) as something used only in situations with active lubrication and/or when severe axial loads are expected, and they've very sensitive to foreign objects or debris. Roller or ball bearings, on the other hand, are more tolerant of dust and debris (as evidenced by their use in driveshafts and wheel bearings), they are not intended to be regularly replaced maintenance items, and they're ideal for situations where they're providing a smooth bearing surface for an object to rotate on and are not subject to heavy axial other loads. All of these features would indicate that a roller or ball bearing pivot is by far the superior mechanism for a knife pivot.

Washers certainly have a cost and complexity advantage, but bearings are technically superior. I know there have been knives where the bearings were problematic, but that's a case of poor engineering, not an inherent flaw with the mechanism.

Well my job last 35 years was exactly that , motorcycles and cars service . And if you do the same , you should know that all bearings on motorcycles or cars that have been exposed to environment / dust , water, moisture , sand , mud .......... / ARE sealed bearings .Some of them with double lip on simering ...........What we have in knive is exposed lubricated ball and that simple call dirt to catch Next , here we have case where the bearing rotates only 180 degrees and steel ball for bearing are around 62-64 Rockwell hardness .Titanuim / in this case race of ball / are little above 40 Rockwell .How long will withstand that combination if you use knife for real ? Of course, in front of the computer in the office there is no fine sand , but if you go on fishing or camping in the mountains , very soon you'll be regret .....You can say what you want but washers are more durable on the sand and all dirt .........and that is fact

 

[Natlek]

Actually Max Archer I think you have it backwards. Ball and roller bearings are commonly known as "anti-friction" bearings and their primary use is in non-static and not low speed loads. In a car engine the most commonly used bearings are plain bearings. The are on the crank shaft, the piston rods, and the camshafts. Why? A few reasons. First is that less parts means lower cost. Second, they stand up to the high loads they experience when the engine is just starting and there is very low speed involved. Lastly, they are extremely reliable and usually outlast the rest of the engine, even the whole car, if the engine is maintained properly. It is not unusual that the ball bearings in the wheels and the throw out bearing in the clutch to need replacing at least once in a car's lifetime. You are correct that they are less tolerant of contamination between the mating surfaces of the lubricant than ball bearings, but the contamination of a plain bearing depends on the spacing between the surfaces and the size of the particles. The movement of a washer type bearing in a knife pivot does not promote entrance of particles if adjusted correctly. I am not saying that washer pivots in knives cannot be contaminated, just that is not promoted. Dust will eventually creep in and require cleaning and re-lubricating.

Ball bearings are designed for high speed movement where the friction on the lubricating wedge of oil or grease becomes a real problem for plain bearings. They do not tolerate high loads at low speeds and they are highly de-rated for their load capacity at low speeds and when stationary. They also suffer point contact fatigue between the bearing and the rolling surface. This causes what is commonly referred to as Brinelling where the hardened surface overlying the softer subsurface deflects under load and fractures and the spalls away causing pits the surface. This quickly accelerates and becomes complete failure very quickly. Hard particles that contaminate the interface between the ball and the surface can start the process early and/or exacerbate the situation very quickly.If the contamination is softer than the surface of the ball and races, then it is easily displaced and hardly affects the performance of the bearing, except if it prevents the ball from rolling and makes it skid instead. In this case you start a rough surface which then quickly begins to spall. There is a reason that ball bearings are sealed from the environment in any design made for longevity. They will have shields or seals to prevent the entrance of contamination particles and to seal in the grease so that it cannot escape. Ball bearings are more forgiving of temporary loss of lubrication as they roll whereas the loss of lubrication in plain bearing usually leads to instant and permanent damage. A ball bearing without seals allows instant entrance of particles and instant contamination of the bearing. The material composition and the size of the particles will determine if they will cause failure or not but they get in without impediment.

A properly designed and lubricated plain bearing has a theoretical lifetime of forever. A ball or roller bearing has a limited theoretical lifetime regardless of how well maintained or lubricated. Each have their uses and benefits.

Thank you :thumbup: you explained just as it should.............

 

[Artifakt]

You know I'm new here but why are you so obsessed with the idea of ball bearings being bad? Their just a part on a knife nothing more. Are you trying to get people not to buy them. If you're unhappy with them just don't buy them. Are you planning of making some here unhappy with their purchases. In my mind I just can't understand your motivation for this, it's a no win situation.

Cash I did read the other thread he started and he did get attacked for his opinion. He started this thread by saying he was only looking for data from around the forum on the two pivot types. No emotional opinions just what there personal experiences are for data collection. Why are you making this into exactly what he is trying to avoid! I don't believe he has an agenda he just wants user experience information. Back down and lighten up man.


Sent from my iPhone using Tapatalk

 

[Seneca18]

Well my job last 35 years was exactly that , motorcycles and cars service . And if you do the same , you should know that all bearings on motorcycles or cars that have been exposed to environment / dust , water, moisture , sand , mud .......... / ARE sealed bearings .Some of them with double lip on simering ...........What we have in knive is exposed lubricated ball and that simple call dirt to catch Next , here we have case where the bearing rotates only 180 degrees and steel ball for bearing are around 62-64 Rockwell hardness .Titanuim / in this case race of ball / are little above 40 Rockwell .How long will withstand that combination if you use knife for real ? Of course, in front of the computer in the office there is no fine sand , but if you go on fishing or camping in the mountains , very soon you'll be regret .....You can say what you want but washers are more durable on the sand and all dirt .........and that is fact

I use my knives for "real" everyday on a very dirty construction site and I have not had a bearing pivot knife fail on me. Bearing pivot knives have proven to me that they can withstand dirty environments in a real world everyday application. I've had Sevenzas get gritty over time but never my bearing knives. My everyday work knife had been the Benchmade Proxy and I use it hard. I am also pretty OCD about the action on my knives and if bearing knives had any issue I would be the first to jump off the wagon.

 

[Aldebaran]

So after all the discussion and anecdotes, it seems that the majority who have reported have had little or no problems with ball bearings in bad environments. Theory and practice in one area sometimes can be wrong in another area of use. The sample here was small and self reporting. It is actually a very poor poll for correct information but the reports show I should reconsider and I have. As I stated before in my other thread I have a ball bearing knife on the way. Thank you to those who actually provided your experiences.

 

[PURPLEDC]

Well my job last 35 years was exactly that , motorcycles and cars service . And if you do the same , you should know that all bearings on motorcycles or cars that have been exposed to environment / dust , water, moisture , sand , mud .......... / ARE sealed bearings .Some of them with double lip on simering ...........What we have in knive is exposed lubricated ball and that simple call dirt to catch Next , here we have case where the bearing rotates only 180 degrees and steel ball for bearing are around 62-64 Rockwell hardness .Titanuim / in this case race of ball / are little above 40 Rockwell .How long will withstand that combination if you use knife for real ? Of course, in front of the computer in the office there is no fine sand , but if you go on fishing or camping in the mountains , very soon you'll be regret .....You can say what you want but washers are more durable on the sand and all dirt .........and that is fact

Actually quite the opposite of fact. Its opinion. And many people with bearing pivot knives in real work environments have no issue. And having the bearings exposed helps flush debris if needed. I see you had no comment on the video showing two ikbs knives tossed directly into a bucket of sand with no ill effect. Any knife that folds is going to be subject to maintenance. This reminds me of the whole revolver vs clip fed gun debate. The real question here is how many years have to go by before those who dont use these knives will give it up and actually admit they may not be the evil they think they are. If you have actual proof otherwise lets see it. Oherwise its just you thinking out loud with no real basis. I dont care what car engines use or wheel bearings. We are talking knives. Lets see a video of a failing bearing pivot knife. This crap that these knives only see a desk job is pure ignorance and it should have been snuffed out with the numerous testimonials over the years from actual users of the products.

 

[Sonnydaze]

Lots of folders with bearings, washers...and never a failure.

 

[PURPLEDC]

I think one thing that I can admit is that washers are probably more robust. But only in regards to forces I would not subject a folding knife to in the first place. You can always build a knife that is thicker and stronger. The question is if you have a folder than can handle 100 pounds of lateral force without damage and a folder than can handle 200, does it really matter if lateral force is not something you will be subjecting your knife to? To me a folding knife is a compromise. It is a tool of convenience. I don't believe despite people doing so that they were ever created with batoning in mind. Or prying a car door open. Knives to me are designed to do one thing. Cut stuff. And I have never seen a bearing knife that would fail at this purpose. As for dirt and debris I feel an open structure that rinses cleanly and can be blown out with compressed air to be a pretty cool feature. Either way, I think both bearing and washer knives will perform their intended tasks equally. Now if you intentionally subject your knife to situations no folder was meant to tackle I cant really argue against it except to say I wouldn't use a pry bar to cuts stuff so I would use knife as a pry bar. Just seems like a lot of worry that is unfounded.

 

[Mo2]

if your using a folding knife for a fixed blade task... well just use the fixed blade.

I doubt any of these pivots fail otherwise.

 

[Aldebaran]

if your using a folding knife for a fixed blade task... well just use the fixed blade.

I doubt any of these pivots fail otherwise.

Many others have said similar things. Not many people carry a fixed blade of any size as a EDC. Yes some people do I know. Where I live, the rather arbitrary laws do not allow neck knives as an example. The police also have wide discretion to decide to whether a knife is to be considered an offensive weapon or just a tool. This means that a 3" to 3.5"" blade is the maximum you can get away with and it can't be too threatening looking neither. So for an EDC I need to carry a mid sized folder to be seen as being a tool.

Where I live, I can go from city to desert with no help within 1 hour, or even on the road from the "big city" to my home. So for me an EDC needs to be a real EDC in type and size, but also needs to be as good as it can get in an emergency wilderness situation.

 

[Max Archer]

Actually Max Archer I think you have it backwards. Ball and roller bearings are commonly known as "anti-friction" bearings and their primary use is in non-static and not low speed loads. In a car engine the most commonly used bearings are plain bearings. The are on the crank shaft, the piston rods, and the camshafts. Why? A few reasons. First is that less parts means lower cost. Second, they stand up to the high loads they experience when the engine is just starting and there is very low speed involved. Lastly, they are extremely reliable and usually outlast the rest of the engine, even the whole car, if the engine is maintained properly. It is not unusual that the ball bearings in the wheels and the throw out bearing in the clutch to need replacing at least once in a car's lifetime. You are correct that they are less tolerant of contamination between the mating surfaces of the lubricant than ball bearings, but the contamination of a plain bearing depends on the spacing between the surfaces and the size of the particles. The movement of a washer type bearing in a knife pivot does not promote entrance of particles if adjusted correctly. I am not saying that washer pivots in knives cannot be contaminated, just that is not promoted. Dust will eventually creep in and require cleaning and re-lubricating.

Ball bearings are designed for high speed movement where the friction on the lubricating wedge of oil or grease becomes a real problem for plain bearings. They do not tolerate high loads at low speeds and they are highly de-rated for their load capacity at low speeds and when stationary. They also suffer point contact fatigue between the bearing and the rolling surface. This causes what is commonly referred to as Brinelling where the hardened surface overlying the softer subsurface deflects under load and fractures and the spalls away causing pits the surface. This quickly accelerates and becomes complete failure very quickly. Hard particles that contaminate the interface between the ball and the surface can start the process early and/or exacerbate the situation very quickly.If the contamination is softer than the surface of the ball and races, then it is easily displaced and hardly affects the performance of the bearing, except if it prevents the ball from rolling and makes it skid instead. In this case you start a rough surface which then quickly begins to spall. There is a reason that ball bearings are sealed from the environment in any design made for longevity. They will have shields or seals to prevent the entrance of contamination particles and to seal in the grease so that it cannot escape. Ball bearings are more forgiving of temporary loss of lubrication as they roll whereas the loss of lubrication in plain bearing usually leads to instant and permanent damage. A ball bearing without seals allows instant entrance of particles and instant contamination of the bearing. The material composition and the size of the particles will determine if they will cause failure or not but they get in without impediment.

A properly designed and lubricated plain bearing has a theoretical lifetime of forever. A ball or roller bearing has a limited theoretical lifetime regardless of how well maintained or lubricated. Each have their uses and benefits.

That's actually what I was saying. I think a knife pivot is closer to a wheel bearing than a rod or crank bearing. Also, when I was working on race cars, I replaced rod bearings on a regular basis, to the point that with many engines they were considered normal wear items. (The BMW S54 and S65 are prime examples.) I almost never replaced any form of roller or ball bearing, and when I did it was because another component had broken and taken the bearing with it.

You're right that things like wheel bearings are generally sealed, but that's possible with knife bearings as well, though it's admittedly rare. My point was that the problems with ball bearings in knives are a result of bad engineering and if designed properly, they'd be the superior system. In a perfect world, washers will always wear out eventually, while bearings will last forever. We don't live in that perfect world, of course, but fortunately we have both options and can choose whichever fits our needs better. If I'm working in an area with fine sand I'll take an appropriate knife, however it probably won't be a folding knife at all.

Personally, I prefer the fact that in a ball bearing knife, the lack of friction comes from a mechanical process, as opposed to a washer knife where it comes from lubrication. I also like that everything in a bearing knife is hard and solid, while washers are almost always made of softer materials and can be deformed.

Many others have said similar things. Not many people carry a fixed blade of any size as a EDC. Yes some people do I know. Where I live, the rather arbitrary laws do not allow neck knives as an example. The police also have wide discretion to decide to whether a knife is to be considered an offensive weapon or just a tool. This means that a 3" to 3.5"" blade is the maximum you can get away with and it can't be too threatening looking neither. So for an EDC I need to carry a mid sized folder to be seen as being a tool.

Where I live, I can go from city to desert with no help within 1 hour, or even on the road from the "big city" to my home. So for me an EDC needs to be a real EDC in type and size, but also needs to be as good as it can get in an emergency wilderness situation.

I don't see why you need to be able to do everything with a single knife. I live in a place where I can be in the mountains, in the desert, or at the beach within an hour, but the knife I carry every day is tailored for my everyday needs. I have different knives for different jobs.