Bearings and Washers

G

Glenn056

Joined
Nov 26, 2015
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Hey everyone! Gonna start a new discussion thread about bearings and washers and I hope this would be an informative one for everyone to learn from one another. Everyone is entitled to their own opinions and I will respect that.
Here are my personal opinions:

Phosphor Bronze washers:
I think it's the most versatile as it can be really smooth once polished, doesn't flex much and wide ones offer a great stability around the pivot, self-lubricating, with a nice hydraulic feeling when you open and close it slowly.

Nylon washers:
Very smooth and silky when new, but degrade over age and seems pretty easy to damage, not to mention that it flexes quite abit, creating some minor side-to-side play.

Nylatron washers:
The mixture of properties between phosphor bronze and nylon washers. Self lubricating and smooth like phosphor bronze, but does flex alittle, like nylon washers.

Ball-bearings:
Extremely smooth and the ideal choice for most flippers. However they are easy to get grit and lint between them, more so than washers it seems, making them grittier over time until maintenance. Now a personal thought of mine about bearings: I am not too sure whether they offer as good a stability around the pivot as washers, as the blade is sandwich but little ball bearings rather than wide surfaces.
I feel somehow that those "Harduse!!!/Folding Prybar" folders with ball bearings don't quite make much sense, especially with those thick blades and handles and a wide pivot, which are designed to pry and what those hard use folders are for, but the horizontal forces are pressing against the little ball bearings ehich probably might damage them perhaps?
One of such knives is the Chaves Rendencion, and yes although i have no experience with those, i just can't help but to feel that way.

You guys of course do not have to take my words as gospel. So please, i would love to hear your thoughts and opinions about the topic of Bearings and Washers.

Sent from the BatComputer
 
I share similar feelings about bearings, they feel lovely but there's something about the small amount of surface area actually contacting the blade that I'm not too sure about.
You can't go wrong with some thick, polished phosphor bronze washers.
 
Not a huge fan of bearings and flippers. Don't own any. It's what's kept me away from ZTs. If only the 0909 had washers and a thumb stud, I'd be all over it.

Not downgrading them. It's just not my thing.
 
Agree with what the OP said about ball bearings, especially over time a track can be formed on the scale and the action is more likely subject to being gritty than washers. I am actually experiencing this very issue of gritty action with one of my ball-bearing titanium flippers.

I read that Hinderer uses teflon washers instead of phosphor bronze for some good reasons (don't remember what exactly they are though). I tend to believe so because for a high-end knife like xm-18 the choice of washer material is obviously not for the sake of money saving.
 
I think in terms of utility, so the way a knife pivot feels is not that important. But comparing the mechanical strength of washers and pivots? Fascinating.

The washers are a better bet for shock-loading. Ball bearings are able to withstand quite a lot of impact force, but they shatter when they fail. Washers will compress by a tiny fraction of an inch, then transmit the mechanical stress to the rest of the knife.

Bearings win the crush test. They will shatter eventually, but the washers deform first, squishing out the sides of the knife like Play-Doh.

Either of these scenarios implies ludicrous amounts of force, that would destroy either the blade or the lock mechanism first. I understand the framework of the discussion, but it's easy to lose focus and perspective when we're all so deeply absorbed by these technical details. So I'm reminding myself, as much as everybody else.

Thrust bearings are designed to handle much more axial torque than ball bearings. To the best of my knowledge, nobody has scaled them down to knife-pivot sizes, yet. I think a lot of the "ultimate strength" of a bearing relies on metallurgy, and the question of "needle versus ball" bearings in a knife pivot should be for another thread.
 
sharp_edge said:
Agree with what the OP said about ball bearings, especially over time a track can be formed on the scale and the action is more likely subject to being gritty than washers. I am actually experiencing this very issue of gritty action with one of my ball-bearing titanium flippers.

I read that Hinderer uses teflon washers instead of phosphor bronze for some good reasons (don't remember what exactly they are though). I tend to believe so because for a high-end knife like xm-18 the choice of washer material is obviously not for the sake of money saving.
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Oh really? But I think it's kinda strange, with phosphor bronze being more durable than nylon, especially since Hinderers are harduse knives

Sent from the BatComputer
 
I'm kind of curious how a fully enclosed bearing would do. That way, you would have hardened steel surfaces bearing directly on the blade tang, and the slabs.

I would mill matching circles into tag and slabs, and just put a hardened steel ring in, skipping the bearings altogether. Maybe that's a simplistic solution, but if the goal is ultimate strength, I think that would be the way to go.
 
IMHO Roller Bearing like on Shirogorov knives are best, don't know why other manufacturers don't use them instead of ball bearings.

Roller bearings have greater contact area between blade and rollers, which results in faster smoother deployment.
 
Wolf7 said:
IMHO Roller Bearing like on Shirogorov knives are best, don't know why other manufacturers don't use them instead of ball bearings.

Roller bearings have greater contact area between blade and rollers, which results in faster smoother deployment.
Click to expand...
But wouldn't a greater surface contact mean more friction? I've never had any experience with roller bearings so would be glad if more people chimed in on that

Sent from the BatComputer
 
I dont mind either technology. Most of my knives have washers but i do have a zt 0450 that has bearings. I think the bearings work well. I dont perceive any weakness in regard to stength, afterall steel is stronger than bronze. However, i do appreciate simplicty in pocket knives. I consider simplicity to be a key factor in longevity and it is something i take into consideration when buying a knife.
 
Glenn056 said:
But wouldn't a greater surface contact mean more friction? I've never had any experience with roller bearings so would be glad if more people chimed in on that

Sent from the BatComputer
Click to expand...

Well, like most things about knives, it's a compromise: more bearing surface, more friction. Less bearing surface, less friction. The exact amount of surface area that your bearings can touch is governed by the length and diameter of the roller bearings.

Measure the ID and OD of your bearing races, find the area of each circle, and subtract the ID from the OD, to find the surface area of your race ring.

If you divide that surface area in half, you can work backwards to the maximum diameter of each of your bearings. But my math fails me, at this point.....
 
Give me some wide polished bronze washers any day of the week. Bearings are fine for art knives, maybe not work knives that will get messy and see lateral forces in my opinion. The ZT0909 isn't that bad because it's steel bearings rubbing against thick steel liners, at least a track wont be cut into the liners as bad as some titanium liners or scales. But washers would've been better IMO for what the knife is marketed as. Washers for me thanks.
 
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I love bearings. So freaking smooth. Just blow out the pivot(s) with an air hose every few days to keep gunk out. I have a balisong that runs on bearings and all I can say is wow, freaking incredible.
 
This:

oyDOS9m.jpg


Scaled down to knife-size, would be about as good as you can get. The bearings are conical, allowing them to be closer together, so there are more of them in the race than there would be with needle bearings or balls.

Machining cone-shaped bearings that are less than 1/8" in length would be quite a feat. They might have to be sintered, and I have no idea how heat treating would be done.
 
Yes - I think it is time for manufacturers (ZT?) to reconsider the bearings they have been using. The roller bearings would be a much better choice IMO: they won't wear down the ti scale as fast as ball bearings and I believe the knife would still be extremely smooth (so added friction should not be a problem at all). But wait, the rollers need to be mounted on a steel frame correct? That may increase the complexity and the cost?
 
Shorttime said:
This:

oyDOS9m.jpg


Scaled down to knife-size, would be about as good as you can get. The bearings are conical, allowing them to be closer together, so there are more of them in the race than there would be with needle bearings or balls.

Machining cone-shaped bearings that are less than 1/8" in length would be quite a feat. They might have to be sintered, and I have no idea how heat treating would be done.
Click to expand...

I wonder if it's similar/same one to bearings used in pivotless ZT-0606CF?
 
Wolf7 said:
I wonder if it's similar/same one to bearings used in pivotless ZT-0606CF?
Click to expand...

Now we need somebody to take apart a 0606.

Anybody.....?

Um.

"Designed by RJ Martin and built by Matt Martin, the 0606CF‘s pivot cartridge features loose ball bearings in a hardened-steel bearing race for an incredibly smooth opening—and virtually no pivot wear during the knife’s lifetime."

From ZT's Tumblr feed. A hard steel race, which is a good thing. But not needle bearings, which would would be even better.
 
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Been using IKBS as Andre Thorburn does it for years now with no issues. Dont know what people are complaining about gunk in the pivot etc. If you can clean a slipjoint you can clean any knife without taking it apart.

When done right they are all good. Just different.
 
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