Tungsten-Carbide pivot bearings?

[Shorttime]

Tungsten-carbide is, of course, the go-to for milling tools, being extremely hard.

It is a ceramic/metal matrix, and that makes it "more brittle" than steel, but "brittle" is a relative term in this context.

As a material for making knife bearing pivot balls, it would have to be treated awfully badly to actually break, and the blade would probably chip long before that.

Obviously, there is no mechanical reason why it could not be done.

But would it be worth it?

 

[powerslave]

Maybe price? It seems to me that Tungsten-Carbide is more expensive than si3n4.
Is here anyone who managed to crack si3n4 bearing?

 

[Mo2]

has anyone done any scientific testing... and why isn't steel good enough for the pivot?

for ball bearings steel or ceramic are fine.

ceramic detent ball is recommended over steel but for bearings I don't think there is a big concern... tho ceramic are more brittle if massive torsional forces happened it could crush those ceramic bearings with ease.

 

[Lapedog]

I actually think if anything it might be detrimental.

The harder bearings already have a tendency to dig grooves into the titanium scales.

 

[PURPLEDC]

The real issue here is tungsten weighs a lot more. And in the application of a knife bearing it really wont provide much more benefit to the all ready incredibly hard silicon nitride bearings. Especially given the extra weight that would be involved as most companies look to be trying to reduce the weight of their knives. But regardless of my personal views, tungsten bearings do exist and I have seen a couple random Chinese makers claim they are using them but I have not seen any in person.

I actually think if anything it might be detrimental.

The harder bearings already have a tendency to dig grooves into the titanium scales.

Only on the few knives still made without hardened inserts. And even then the wear ceases after a certain point and you will essentially just have a cold rolled race for the bearing. The guys who make ikbs start with a flat ti cut out and force a cold rolled race. But tungsten isn't going to wear any faster that Si Ni ceramic which is the most common ceramic being used. The wear is going to depend more on how often the user cranks down their pivot and how often they open and close the knife. But there has never been and IMHO will never be a situation where a bearing wearing into the titanium causes any issues with performance and most people would never even know unless they opened their knife. But no failure is going to occur.

 

[Lapedog]

I actually put forward the idea in another post about bearings work hardening by cold rolling the Ti they roll across, thus creating a hardened race. I never got an answer whether or not this is true and actually happens.

I think what people are most scared of is situations like on the Advocate where the bearings destroyed the inserts. Also I am not certain that most knives come with hardened steel inserts now. On the other hand i've had no problems with my older knives that had no inserts.

 

[PURPLEDC]

I actually put forward the idea in another post about bearings work hardening by cold rolling the Ti they roll across, thus creating a hardened race. I never got an answer whether or not this is true and actually happens.

I think what people are most scared of is situations like on the Advocate where the bearings destroyed the inserts. Also I am not certain that most knives come with hardened steel inserts now. On the other hand i've had no problems with my older knives that had no inserts.

Most knives with bearings do have hardened steel inserts or washers built into the knife. The only company that wasn't doing this was ZT for the most part along with some custom makers but they force the race instead of just letting it ride on flat titanium. But yes as the bearings wear into the titanium it compresses and cups the bearings supporting them. It stops at a certain point and to this day I have never seen any evidence of any problems occurring with the exception of a visual difference in the titanium.

 

[Mo2]

The real issue here is tungsten weighs a lot more. And in the application of a knife bearing it really wont provide much more benefit to the all ready incredibly hard silicon nitride bearings. Especially given the extra weight that would be involved as most companies look to be trying to reduce the weight of their knives. But regardless of my personal views, tungsten bearings do exist and I have seen a couple random Chinese makers claim they are using them but I have not seen any in person.


Only on the few knives still made without hardened inserts. And even then the wear ceases after a certain point and you will essentially just have a cold rolled race for the bearing. The guys who make ikbs start with a flat ti cut out and force a cold rolled race. But tungsten isn't going to wear any faster that Si Ni ceramic which is the most common ceramic being used. The wear is going to depend more on how often the user cranks down their pivot and how often they open and close the knife. But there has never been and IMHO will never be a situation where a bearing wearing into the titanium causes any issues with performance and most people would never even know unless they opened their knife. But no failure is going to occur.

I cleary notice if there is no bearing races. i won't buy them if they don't. I am really disappointed in makers cutting costs by not doing this, especially on 200$+ knives, steel bearings or not.

most of the 2017 zt lineup doesn't. unless that is if the show side is carbon. my 801brz doesn't have them. worst action I have.

 

[Lapedog]

That's really weird. My older first gen 801 has some of the best flipping action of any of my knives. I personally have never had a problem with bearings running directly on titanium. I think that it isn't usually a problem unless you crank down the pivot harder than it should be. Then again there is a possibility I just havent flipped my knives enough for a problem to occur.

However if the bearings are evenly wearing a cold rolled hardened race then I don't see it being a problem as long as that race wears evenly and the pivot can be tightened to take up any resultant slack.

Oddly enough most my knives that run on bearings do not have steel inserts. Then again many of them are ZTs.

I miss some nice simple PB or teflon washers. A well adjusted knife rides nearly as smooth on these as bearings. If a knife has bearings and I like the knife I will still buy it. I just think that ditching PB washers was sort of unnecessary.

 

[PURPLEDC]

I cleary notice if there is no bearing races. i won't buy them if they don't. I am really disappointed in makers cutting costs by not doing this, especially on 200$+ knives, steel bearings or not.

most of the 2017 zt lineup doesn't. unless that is if the show side is carbon. my 801brz doesn't have them. worst action I have.

Yeah. I'm not really a fan of how ZT does it. But I don't think its absolutely paramount to put the hardened inserts in. But my question is why not? Its simple, wouldn't be all that costly to do and it would give customer piece of mind. Its cool with me though, I just vote with my wallet.

 

[John_0917]

Well, they won't rust (like my Emerson 440C bearings have severely) but as mentioned they're much harder than the blade steel and probably the liners also so it may not be a good long term setup.

 

[AF]

My ZTs flip as well as any knives I've experienced. 0562 and 0920.

 

[Wowbagger]

Obviously, there is no mechanical reason why it could not be done.

Obviously there is no mechanical reason TO DO IT.

Why in Bob's name would you want that in a mechanism that gets relatively VERY LOW cycling / VERY VERY LOW rotationally speed, almost zero load while pivoting . . .

by the way the only reasons for ceramic in a knife is rust resistance and light weight.

Enlighten me.

 

[Lapedog]

Have you guys seen some companies are fooling with making tungsten carbide knives? Sandrin is the major player. I saw another guy that uses tungsten carbide for the edge and fibre reinforced aluminum for the rest of the knife.

 

[spykez]

Bladewise, I can imagine some sort of edge coating but would it last long? Also, is tungsten carbide more brittle?

 

[Shorttime]

The opinion so far seems to be that it could be done, but there is no compelling reason to do it, which is what I thought, too.

The production knife market has a lot of knives competing for buyers' attention, and the only reason (if it's properly a reason), that I could think of, is as a marketing feature. I wanted to see what others thought, and it's always interesting to see where a discussion goes.

 

[HowAmI]

What about Titanium bearings? I don't see why we couldn't have Titanium bearings (caged and free options) so that it wouldn't cold roll into the scales but at the same time function the same as Ceramic or SS?

 

[PURPLEDC]

What about Titanium bearings? I don't see why we couldn't have Titanium bearings (caged and free options) so that it wouldn't cold roll into the scales but at the same time function the same as Ceramic or SS?

****apologies for the wall of text. You dont have to read it i just geek out about the finer details. ****


Titanium just isnt a good bearing material. It simply cant harden enough for long term wear resistance. And its polishing characteristics are way below that of ceramic and steel which surface finish quality is very important in a bearing. It would likely be very costly to do so. And there simply is no real advantage.

Regardless the cold rolling isnt so much caused by the material of the bearing but the repetitive cycling and the constant increasing pressure of the pivot. Many guys do regular maintentance on their knives and each time they ajust their pivot after disassembly or just because they dont use loctite. Every time this is done you compensate for the wear your knife has had since the last cleaning or adjustment. So the pivot screw goes in a tiny bit further everytime that cycle occurs. This is what really puts the trench in a ti scale.

Ti bearings would likely roll a race anyways. It just wouldnt happen as fast because of the softer material. But also because the bearig would be deforming as well. Some have this misconception that two materials of equal hardness wont damage each other. Or even worse that a soft material cant harm a harder material. This is not true as several other factors determine such a thing such as velocity, mass and the shape of each object. For instance an aluminum ice pick if such a thing exists could easily scratch a pvd coating or even a dlc coating because coatings are thin and while te coating itself is hard its only as scratch resistant as its bond to the metal its coating. Some have challenged me on this.

 

[Lapedog]

****apologies for the wall of text. You dont have to read it i just geek out about the finer details. ****


Titanium just isnt a good bearing material. It simply cant harden enough for long term wear resistance. And its polishing characteristics are way below that of ceramic and steel which surface finish quality is very important in a bearing. It would likely be very costly to do so. And there simply is no real advantage.

Regardless the cold rolling isnt so much caused by the material of the bearing but the repetitive cycling and the constant increasing pressure of the pivot. Many guys do regular maintentance on their knives and each time they ajust their pivot after disassembly or just because they dont use loctite. Every time this is done you compensate for the wear your knife has had since the last cleaning or adjustment. So the pivot screw goes in a tiny bit further everytime that cycle occurs. This is what really puts the trench in a ti scale.

Ti bearings would likely roll a race anyways. It just wouldnt happen as fast because of the softer material. But also because the bearig would be deforming as well. Some have this misconception that two materials of equal hardness wont damage each other. Or even worse that a soft material cant harm a harder material. This is not true as several other factors determine such a thing such as velocity, mass and the shape of each object. For instance an aluminum ice pick if such a thing exists could easily scratch a pvd coating or even a dlc coating because coatings are thin and while te coating itself is hard its only as scratch resistant as its bond to the metal its coating. Some have challenged me on this.

Didn't you see some companies are claiming their carbonitride titanium coating makes the knife 10x stronger than steel!?

Are you implying that Camillus would lie to or mislead us!

 

[HowAmI]

****apologies for the wall of text. You dont have to read it i just geek out about the finer details. ****


Titanium just isnt a good bearing material. It simply cant harden enough for long term wear resistance. And its polishing characteristics are way below that of ceramic and steel which surface finish quality is very important in a bearing. It would likely be very costly to do so. And there simply is no real advantage.

Regardless the cold rolling isnt so much caused by the material of the bearing but the repetitive cycling and the constant increasing pressure of the pivot. Many guys do regular maintentance on their knives and each time they ajust their pivot after disassembly or just because they dont use loctite. Every time this is done you compensate for the wear your knife has had since the last cleaning or adjustment. So the pivot screw goes in a tiny bit further everytime that cycle occurs. This is what really puts the trench in a ti scale.

Ti bearings would likely roll a race anyways. It just wouldnt happen as fast because of the softer material. But also because the bearig would be deforming as well. Some have this misconception that two materials of equal hardness wont damage each other. Or even worse that a soft material cant harm a harder material. This is not true as several other factors determine such a thing such as velocity, mass and the shape of each object. For instance an aluminum ice pick if such a thing exists could easily scratch a pvd coating or even a dlc coating because coatings are thin and while te coating itself is hard its only as scratch resistant as its bond to the metal its coating. Some have challenged me on this.

Read it all without a problem . Anyways I've heard of the Titanium not having the characteristics but never looked into it as I don't have a problem with SS or Ceramic.