New ZT0550 Thread !!!

40Degrees said:
I suggest getting one of those springy things that increase thumb strength for gripping power. They also have those squeezy ball things that release tension. That may also work.
It's a man's knife and requires man power to use it.

Seriously, there have been a few other posts with possible solutions.
1) tighten up all the screws
2) you said you tried pencil. But, instead of pencil get real graphite that comes in a tube.
3) read my suggestion and just work the hell out of it to polish up the tang.
4) NO luck with 1-3? Send it in. KAI customer service is second to none.
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I don't think you understand. I don't need clarification on a "man's knife". I have big bear paws. When I say it takes two hands to close it, I mean it takes several minutes of two hands to close it, IE I have to use something to pry it closed. I'm not talking about a stiff frame here. My strider is stiff. This is jammed. Almost impossible to close.

-Freq
 
Stainz said:
Hey, Gnarly, etc, I got one!

Good news/bad news. My local pusher/enabler had three last Saturday. The demo was fine, so I just picked an unopened box - should have looked! The knife has a perfect edge - super sharp - and perfect, QC wise. Oops - the closed blade is slightly off-centered... and the action is stiff.I removed the clip, as I do all of my knives, and loosened the pivot and both side screws. I used a needle applicator and some clock oil on the pivot bushings and the lockbar ball. I then retightened the side screws and tightened the pivot until the action was acceptable. It's better, but the blade seems pushed to the G10 side - maybe 40% over; 60% to the lockbar side. Loosening the pivot screw gets it closer to the G10 side.

I like the knife - and it's action is acceptable - opens and closes one-handed, but not a 'flicker', that's for sure. I don't know if it is worth returning it for the slightly off-centered while closed nature or not. It is aggravating. The lockbar overlap is 40% or so - and released by my thumb while ty finger rotates the blade - with no problems. I compared the last few degrees of opening - until lockbar 'drop' with my 0301 - the 0551 is slightly slicker. Mine is #622. Should I leave well enough alone - or send it to the 'spa'? Have others noted a closed blade position determined by pivot screw tightness nature in their example? Thanks!

Stainz

PS One positive note... the store gave me a 'good customer' discount - left enough, with s/t, from the MSRP for a Mex lunch, which my wife wanted after seeing the 'Mexican steel blade' - El Max!!
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Stainz,

Mine (#548) has broken in to be a flicker, I imagine it will take a little breaking in... I still get the occasional lock bar stick, but I just keep throwing a little sharpie on there and it goes away. The tang on mine came polished (not sure if anyone else's did) but I definitely still think it's got a ways to for break in... A super steel necessitates a super break-in I think... My .02 anyway, the knife rocks, I don't think you'll regret it.

Regards,
-Jack
 
40Degrees said:
Hey RD I'm pretty sure this guy jj sold his ZT for cost. Some people, they just expect a $200 knife should be more like a $400 one. One could only wish that were possible...

and yea some very fine sandpaper and a little know how goes a long way for all us knife nuts. :)
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I'm not a guy (you ever hear of a guy named Jill?) but, yes I let mine go at cost. Nothing wrong with it, I just decided after looking at it, not to keep it. I have other knives I like better. As for the at cost, I didn't feel like trying to make a few bucks and merely passed it on to someone who wants one. ( it was worth the trouble of buying it to me, just to look at it in hand) As for my expectations the knife is fine, nothing wrong with it at all for the price. Just wondering about the how and why of a couple of details.
 
It's odd that the 055x seems to have so many lockbar issues given the great, perhaps even on the flimsy side (as far as resistance to pushing over) lockbars on the 0300.

I doubt that the ultra-hard steel is the culprit since it'll be titanium does most of the wearing in. It's not like S30V is sponge-like either.

There seems to be almost no consistency in the production ti framelock world. Both my ti bumps have a slight amount of stick, nothing bad, but my ti tyrade is absolutely flawlessly smooth. Totally linear resistance to unlock from start to finish. That said, my 2nd Tyrade stuck really hard, not impossible or painful or anything, but definitely annoying. My 0302 had no stick at all and was a little past 50% of the tang--indeed, it is by far the easiest to unlock, as far as lockbar resistance goes, of any of my framelocks ever. My 0301 had a little stick, but once you got over that it again was really, surprisingly easy to flex it out of the way.

So even if you have two of the exact same knife they could, feel-wise, effectively have two totally different framelocks. I wonder why this isn't more standardized.
 
Artfully Martial said:
So even if you have two of the exact same knife they could, feel-wise, effectively have two totally different framelocks. I wonder why this isn't more standardized.
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All my Sebenzas and my Star-Tac, have the same feel to unlock the bar.
They do vary a bit as to how far the bar is engaged when locked (most are early one is deep), but they are all smooth and easy to unlock, plus they all have bank vault tight lockup. So, it can be done.
 
jill jackson said:
All my Sebenzas and my Star-Tac, have the same feel to unlock the bar.
They do vary a bit as to how far the bar is engaged when locked (most are early one is deep), but they are all smooth and easy to unlock, plus they all have bank vault tight lockup. So, it can be done.
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Sure, but more relevant to the thread, the consistency seems particularly off on the 055xs...
 
Artfully;
I suggested that simply because I know sometimes bike seat posts made of metal will "weld" themselves to the frame constructed of a different metal... Perhaps composition plays a part? Just a thought anyway...

DISCLAIMER; this post is simply to stimulate conversation! I do not condone the modification of your knife in this manner, and will not be held responsible for anyone's choice to do so!

Perhaps it is the thickness of the lock bar in relation to that of the blade tang? Think of it as a door and door frame, the lock bar being the door and the blade tang being the frame. If the door was too thick for the frame, the edges of the door might contact the frame at some point during the swing open or closed. The way this is different however is the lock bar (or door hinge) the relief cut is such that there would be no binding on the hinge side, and hinge would be allowed to swing open and shut freely. On the opposite side of the frame though (where lock bar meets blade tang) there could be some binding at the corners (especially given the fact that the lock must contact the tang in order to engage), and therefore cause binding when attempting to disengage the lock. It would be interesting to find out, if someone rounded or ramped or otherwise made the lock-bar thinner where it contacts the tang, if that makes it easier to disengage the lock...

DISCLAIMER; this post is simply to stimulate conversation! I do not condone the modification of your knife in this manner, and will not be held responsible for anyone's choice to do so!
 
^Had a zt0551 and sold it for more $ even though it worked fine although it was a bit sticky, which is normal for a new frame lock knife. I have another one dropping in the mail today. I will see how that one is. It could just be the angle and grind on the two (blade/lock bar) contacting surfaces. Nothing a bit of light sanding with xtra fine grit paper can't fix. Which is most likely what KAI would do to it if you decide to send it in.

You can't compare a frame lock to a door hinge. They operate in much different ways. As a carpenter with 20 years exp. I know what I'm talking about.
 
I disagree with you, as someone who has engineered and built goal oriented robots and competed with them successfully for several years... The principle is similar, the relief allows the lock bar to function as if it was on a hinge.

Regards,
-Jack
 
LOL...stick with robots Jack.

the thickness doesn't cause the bar to stick, it's the angle of it. if you have more Ti touching the side near where your thumb touches the bar what is happening is your downward pressure(to close knife) is forcing even more of that TI bar angle into the blade kinda like a wedge.
sanding it down and making it more perpendicular should remove the "wedging" effect.
not having that problem with any I wouldn't know for sure.

Even if I had the problem I think it would be best to send it in. Wouldn't want to give someone the wrong info.(void the warranty) on how to fix their problem...cause it's their knife.

BTW, just got another in the mail. serial # in the 500's and it's perfect. even a baby could close this one...no sticking at all.
2uhtk5l.jpg


Josh
 
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40Degrees said:
LOL...stick with robots Jack.

the thickness doesn't cause the bar to stick, it's the angle of it. if you have more Ti touching the side near where your thumb touches the bar what is happening is your downward pressure(to close knife) is forcing even more of that TI bar angle into the blade kinda like a wedge.
sanding it down and making it more perpendicular should remove the "wedging" effect.
not having that problem with any I wouldn't know for sure.

Even if I had the problem I think it would be best to send it in. Wouldn't want to give someone the wrong info.(void the warranty) on how to fix their problem...cause it's their knife.

Josh
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I will have to disagree with you on the above.

I know a local maker that has tried every angle to stop a TI framelock from sticking and it has not worked. It is part of the TI against steel alloy. On some knives it is more pronounced on others not. However if it does become so bad that one is truly applying brute force to get the thing unlock send it back. Then there is something wrong with the blade/lock interface.

A well know man on this forum making his own knives has stated that one should never adopt the lock to the blade, but the blade to the lock. Sanding it down might work now (and I hope it does for a long time for you) but it might cause bigger problems down the line.
 
jill jackson said:
Artfully Martial said:
There seems to be almost no consistency in the production ti framelock world.
You did say "almost no consistency in the production ti framelock world. "
Which includes CR's knives.
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I concede your point, but my initial claim still stands: there is almost no consistency--I didn't say there is never any consistency. Given the vast number of Ti Framelock models available, even if we add all CRK framelocks and maybe the Lochsa too they represent a huge minority insofar as consistent models (perhaps that statistic would actually be otherwise if we discussed actual numbers produced given that the Sebenza is likely the most common titanium framelock in the world. Nonetheless, I unintentionally left "ti framelock world" ambiguous and it may be construed in either fashion. Given that I am the creator of the statement, I now clarify that it refers to the difference between a given model and not relative percentages of ti framelocks produced in the world).

Nonetheless, upon reflection, I should qualify my claim with noting I mean only to include production knives. I just don't have enough experience handling similar models of custom knives to make that statement.

As to the topic at hand, the differences in lockup properties among the 055x seem relatively extreme compared to other ti models, even from the same manufacturer (i.e., 0300). Especially given the relatively small numbers of 055xs produced so far.
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Speaking theoretically, the smoother the surfaces of the lockbar/tang interface should actually increase resistance to unlock given that there is, although not visibly, a greater deal of contact and consequently friction in that interface. So I theorize, anyway.

I have some experience testing lockwear in ss liner locks, and have swapped out the nested liner lock that locked up too far over and was sticking with a brand new liner lock, and everything else remained identical. The new lock worked great--it locked up earlier and there is no stick, additionally, there is less resistance to unlocking.

When I compared the disconnected lockbars/liners side by side, it was clear that the original lockbar bent maybe a cm further than the new liner (supposedly they were both new, by the way). This is pretty intuitive--the greater the spring tension in the liner, the more force it took to push it out of the way, the greater the lockup and the more "sticking" was observed.

So my current theory is pretty simple. At least to some substantial degree, the spring tension itself has a noticeable effect on the properties of the lock.

This may not explain the phenomenon on every single case of this problem, but it did in my case and it might in yours. Assuming I'm right, one may intentionally overextend the lock in an effort to reduce the tension.

Now, that's strictly theoretical and you proceed at your own risk if you want to test this hypothesis.
 
If your lock is sticking so bad that prying or extreme force is needed to unlock it then its time to send it in.

When a frame lock sticks and binds prying it is probably the worst thing you can do. It will deform the lock face and make it even more problematic. When this happens its better to press the edge into a board putting pressure on the thumb stud/stop pin which lessens the pressure on the lock bar and allows you to easily release the lock in a safe way.

My 0551 was exactly the same, the lock was galling, lock-up was at 90-100%, and when the galling stopped the lock bar simply was at rest behind the tang, yes, not touching and developed vertical play.

No amount of pencil markings or sharpie will fix a bad lock, if its sticking bad then it needs to be fixed.
 
I guess I suffer from the same problem Jill did with her 0551 - she has a better QC example in the Lionsteel SR1 - as I do in my CRK/WC 'zaan. Tighter QC does have a cost - but I thought a ZT bought such! Perfection spoils you. You can certainly approach it closer for a lot less than the 0551 costs, too. Such examples as my Benchmade 630's, Buck 172, and my stock and blem Kershaw 1725SG2, not to mention my other ZT - a 0301 - and all well less than the 0551 cost me. They certainly set the bar high - sadly, the 0551 I have falls a bit short - and just because of it's uncentered blade! The reported variability in QC is astoundingly sad.

Stainz
 
One of my 0551s was sticking so badly that I would have to pry it apart with a quarter. After applying sharpie upon every single opening and working it for around 2 weeks now I can safely say it is near perfect - only sticking in ~ 1 in 50 openings.


So I disagree. I think that you can fix it (wear it in) yourself, it just takes time.



knifenut1013 said:
If your lock is sticking so bad that prying or extreme force is needed to unlock it then its time to send it in.

When a frame lock sticks and binds prying it is probably the worst thing you can do. It will deform the lock face and make it even more problematic. When this happens its better to press the edge into a board putting pressure on the thumb stud/stop pin which lessens the pressure on the lock bar and allows you to easily release the lock in a safe way.

My 0551 was exactly the same, the lock was galling, lock-up was at 90-100%, and when the galling stopped the lock bar simply was at rest behind the tang, yes, not touching and developed vertical play.

No amount of pencil markings or sharpie will fix a bad lock, if its sticking bad then it needs to be fixed.
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