I'm a little new to the knife community and VERY new to the forum, I am curious to know how smooth the ZT0801 is supposed to be from other perspectives, I recently purchased one from a fella on Instagram, awesome deal and a nice guy but when I disassembled it (like I do with every single one of my knives) the bearings were very rusty, after some gun oil and silicon lubricant in the bearings to help clean them up and smooth out the action. Upon reassembly, the knife is not smooth at all, pivot Tweaks don't help at all, however, the blade still fires hard because of its great detent but on closing the blade, it takes effort to do. Any tips on how to smooth it out or where to get new bearings? Or if I even need new bearings. I shot ZT an email a couple days ago with no reply yet so I figured I would see what you guys/gals think.
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Zt bearings?
- Thread starter wfiddy
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- Apr 30, 2013
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- 123
The titanium handles are fairly soft compared to the steel balls, if you or the previous owner got a little carried away tightening the pivot it's possible the balls indented into the titanium race which results in a rough feeling. It's really not difficult to get the pivot screw tight enough to damage the handle, ask me how I know.
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- Jun 13, 2014
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- 1,651
^^What kornphlake said. My new 561 had some pits along the bearing's track in the titanium. Rough but still works.
Is there a chance it was gunked up, you took it apart....it didn't get back together like factory and everything came together and now it's way out of whack?
You may need to send it back. They'd probably return a perfect knife to you. I hope the new bearings work for you though.
You may need to send it back. They'd probably return a perfect knife to you. I hope the new bearings work for you though.
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- Apr 4, 2007
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- 8,578
There is a way to fix your issue. What is essentially happening is the bearings are forming a race. The limited rotation can make it seem rough because the race isnt fully developed. Kai USA as you know doesnt use a steel insert to prevent wear. But neither does Ikoma or korth. They actually force the wear you are experiencing. While it seems rough now, if you were to continue to force that race completely you would experience a very very smooth pivot action. There comes a point where the wear stops. This is because the bearings cold roll that race and it work hardens. then it gets to the point wear the bearings arent going to sink and bite in anymore. You are in the in between stages and may have developed a burr.
I highly doubt there is anything serious going on. Either way Kai will take care of it. Are you sure the perceived lack of smoothness isnt the detent? This is where the majority of friction and issues with smoothness come from. Either the detent ball cracks (ceramic) or it deforms and scrapes along the blade rather than glide. You would hear a scraping sound as the blade moves. Now you did say you experienced a bit of rust on the bearings. Its possible the balls are now pitted and arent rolling as smooth as they should. Backing off the pivot will reduce the load on the bearings and smoothness should come back even if there is play in the blade. But if you back off the pivot so the bearings arent fully under load and its still not smooth its more likely a problem with the detent.
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I'm pretty accomplished at taking my stuff apart,and there was no distortion on the detent or in the track of the detent of any kind beside a tiny flat spot on the ball itself which is to be expected. I'm not too worried about it based on the info I have now
CJZ
Gold Member
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- Dec 18, 2012
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Oh wait, did you put oil back in the pivot? This happens to me a lot, I take apart a knife, clean it and then opening and closing gets difficult. Usually because there's no lubrication in there. 
Edit: Just read the post again, disregard this post haha
Edit: Just read the post again, disregard this post haha
Haha no worries, thanks for the tip though, I always use a little spot of high speed gun lubricant on all my knives for maintenance, my Brous T4 loves the oil I use and it falls shut with a fully tightened pivot. I know my early around knives very well I just think I need to have ZT take a look at it
- Joined
- Jan 22, 2011
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- 3,193
This. Sounds like the detent ball more than the bearings. The detent track and ball can look totally normal but a small amount of contaminant can realllly rough up the action. Unless the action is 'ratchet' like I doubt the bearing race is deformed.
Here is a video from John Grimsmo showcasing the phenomenon I think your problem is:
[video=youtube_share;Bt0FAHDc4gQ]http://youtu.be/Bt0FAHDc4gQ[/video]