0560 Ball Bearing life expectancy

M

maico

Joined
May 11, 2011
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Watching this disassembly video it's clear the ball bearings are wearing a circular groove on the softer titanium side. I wonder if this is going to cause problems down the line, or will it just bed in up to the point of the flat ball bearing holder ?

http://www.youtube.com/watch?v=Th4uWqqVnz4
 
I think your idea that it'll likely bed into the point of the bearing washer is probably more accurate, but there may be a life expectancy on flips. I took mine apart last night, and the bearings are set in a way that, if you put pressure on one side, they will kind of pop up a bit more on the other side. However, they won't come out, and there's a maximum protrusion point. In my mind, that means that the groove can't possibly get so deep that the bearings cannot do their job.

Even if it were an issue down the road, I can't imagine a personal scenario where I'd flip mine enough for it to matter. Still it's a good thought and an important question. Lets hope some ZT folks chime in with some stress test perspective.

Thanks for the vid link, too.
 
Same here, I would be quite interested to hear an expected "life expectancy" of these washers so we can better gauge it [if there is a need to replace them at a certain point down the road] Reason being I am "that guy". Since getting my Sebenza I have probably open and closed it near like 25k a year, perhaps 50-100+ times a day easy. I just sit there and play with it while watching tv etc :p. So most of my knives would probably hit the wall via wear from opening + closing vs hard use lol [albeit I categorize my knives so I have "beaters" if you will - gayle bradley [spydie] etc]. And I am sure I will wear it like a mofo on my 560.
 
I was thinking about life expectancy the other day aswell, but I was more concerned with the detent than the bearings. Where the detent balls slips off the blade, I am worried the detent ball is going to wear the area down to the point the detent will be pretty much non-existent. I only say this because I've watched since I received the knife brand new that the detent changes more and more as its flipped open more times. How many flips will it take before the blade just starts swinging freely? I am very interested in these questions aswell and hopefully someone can give us answer or atleast someone with more know-how with this sort of thing will pipe in.
 
I really wouldnt worry about it. As the bearings wear that little groove its actually compressing the metal and doing what is called "cold rolling" a bearing race. As this happens the race is actually getting more hard in the process and eventually it should stop. This is how IKBS folders are made. But the process is done at an accelerated rate so that the bearing race is fully formed before the sale.
 
You guys worry too much. Just use the damn things and if/when they wear out, sent them to KAI for warranty work.
 
travclem said:
You guys worry too much. Just use the damn things and if/when they wear out, sent them to KAI for warranty work.
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I figure, by the time mine wears out, I'll want something else. :D

Maybe a ZT0991.

:D

Moose
 
PURPLEDC said:
I really wouldnt worry about it. As the bearings wear that little groove its actually compressing the metal and doing what is called "cold rolling" a bearing race. As this happens the race is actually getting more hard in the process and eventually it should stop. This is how IKBS folders are made. But the process is done at an accelerated rate so that the bearing race is fully formed before the sale.
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Pictured here:

http://www.ikbsknifetech.com/20801.html

On the ZT opening the knife up and getting rid of the swarf build up sounds like a good idea.
 
I think this issue is something KAI/Kershaw/ZT must have thought about and tested for, I would like to know the answer as well. I flip mine a lot also, its addicting and apparently annoying to some people. I think its good handling practice, getting used to the knife so you can get it deployed quicker.

I heard somewhere that the life expectancy for the torsion bars is like 10K flips, so if the 0560/1 is good for 25K flips (lets say) than it would be significantly longer lasting mechanics of the knife, which will cost KAI less in warranty work and keep the consumer happier longer.

Also I wonder if bronze phosphorus washers actually last longer than the KVT system, this might be a touchy subject, but I would like to know.
 
I don't think its a secret, the bearing race is polymer, if I remember correctly.

I am more interested in the life expectancy, I wonder if they did any testing on the matter, or if they care to share that info.
 
bluejayburly said:
I don't think its a secret, the bearing race is polymer, if I remember correctly.

I am more interested in the life expectancy, I wonder if they did any testing on the matter, or if they care to share that info.
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You can rest assured that you could never wear the bearings though the Ti in your life time. It's kind of a moot point. Once they wear a track into the Ti, the wear rate slows WAY down. If you did nothing but flip this knife constantly every single day until you die, you still probably wouldn't wear the bearings out.

The lock will fail much sooner than the bearings, so again it's kind of a moot point. Although if you want to know just for knowing's sake then that's cool too.
 
maico said:
Seems to be some sort of secret unobtainium judging by the complete silence on the matter !
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Mine is made of blue plastic. I'm not sure what the chemical composition is, but I know its blue.

I been flipping the hell outta mine since I got it, and I'll take it apart tomorrow and take some pics, if you want.

Bearings usually wear out because of heat, and lack of lubrication. With this knife, there is no way you will ever build up enough heat to cause the bearings to swell.

Plan on the bearings being around for a while.

Moose
 
So do you guys think the ball bearing detent should last just as long?
Does the ball bearing on the frame lock spin or not? I can't really tell. How do they hold it in so it doesn't fall out but still spin freely?
 
If it is like most framelocks, the ball detent does NOT spin and is pressed into the lockbar and peened into place permanently.
 
bluejayburly said:
So do you guys think the ball bearing detent should last just as long?
Does the ball bearing on the frame lock spin or not? I can't really tell. How do they hold it in so it doesn't fall out but still spin freely?
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Does not swing freely. Look at the detent when the blade is open, you will see that it has worn in and created a flat spot on the ball.

The ball detent (like the bearings) will far outlast the blade and lock on the knife, so again it's a moot point. :)
 
Yea, I don't feel there are any reasons for long term concerns with either KVT or the detent.
 
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