Hard Opening ZT 0550

H

Harpoon1

Joined
Apr 3, 2011
Messages
147
I've had a "0550" about a week or so now and it is without a doubt, the hardest opening knife I have ever had. It seems to me the problem is more one of geometry, and the thumb-stud location, than being a little to "stiff" from being new. Feels like I'm pushing more length wise on the thumb-stud, instead of out and away from the frame.

Can't really change the geometry, so, I've backed off the the tension on the blade, until the blade nearly touches the sides when closed and there is some blade play in all directions. Still won't open easily. You can tell there is less tension once the blade breaks over the "hump", but, breaking over that hump is still nearly impossible.

I have literally 50-75+ other folders with thumb-studs and "Spydie holes" and have never had this problem before.

And ideas on how to weaken/soften the initial opening "hump" ??????
 
Thomas,

I'm not sure how to characterize it, other than the detent feels "crisp", solid. It feels smooth also, no dragging or hanging up on anything. It still takes considerable force to even open it with two hands, by pulling on the thumb stud with the other hand. It just feels like there is to much force holding the blade closed. Once you get over the hump, the first 1/8-1/4 inch, it's fine. Feels great all the way to lock-up. And the lock-up is perfect.

Thanks.
 
Try loosening the pivot a little. That should help a bit. Also keep track of where your fingers are on the locking side of the folder. You might be inadvertantly pressing the lockbar into the blade increasing the detent without realizing it.
 
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That doesn't sound like a pivot issue. Mine is #0401 and from day one with no adjusting it flies open like an assisted opener with very little pressure. You might have to send it in. Could it be the detent ball is going in too deep?
 
see if the thumbstuds are centered I had to send one back that was off by a very small amt and it made it seem as if something was wrong with the detent.
 
Also try opening it left handed. If it is easier left handed, you are unknowingly putting pressure on the lock bar when opening it right handed. I have the 0551 and this was my problem at first till I modified the way I held the knife while opening it.
 
I had the same problem with mine. I don't remember which post I saw it in but the issue was addressed in regards to opening technique. Instead of pushing outward, you push more upward then outward. Takes a little getting used to but works perfectly.
 
Edlex,

Mine is #604 and that's exactly what it feels like. Either the ball is seating to far down in the detent and/or there is to much pressure/force holding it in the detent.

Jwolf90,

How would I know if its centered or not? What should I look for?

Nightman,

Good idea. Tried it lefty and it still felt pretty much the same though.

Americanbulldog1,

Yep, and this gets back to my original post about the "geometry" being a little different. Holding the knife flat in my right hand, pushing at 3'oclock on the thumb-stud, it's nearly impossible for me to open the knife. At the 4 o'clock position it opens but, it's still very, very hard to break the detent. Turning the knife upright in my hand, with the blade now positioned vertically, and pushing from the 5-6 o'clock position the knife opens much easier. However, having said that, IMO, it is still to hard to break the detent. But, using this "new" technique does make it more tolerable. I'll dig through the archives and see if I can find that post you mentioned.

To Everybody,

I'm considering taking the knife apart and "adjusting" the lockbar to relieve some of the force/pressure on the ball and detent. I sure by doing this I will void the warranty and I'm ok with that, just curious to know if I'm on the right track? Is this particular knife a real PITA to reassemble?

Thanks to everyone for their help, I appreciate it.
 
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I'd send it back to KIA and let them fix it. They'll know what to do and you should have it back soon.

The answer to taking it apart is no it's not a pita to take apart and resemble. If you've taken other frame locks apart it will be the same.
 
My 0551 is also harder to open and, like you, I think it is partially the design. I can open it fine but flicking open is a no go just using the thumb studs. However, with all my folders with thumb studs and holes, I find it much easier to flick them open by pushing parallel to the handle instead of out which is more perpendicular. I think if you try your new technique with your other folders you will be pleasantly surprised. Sort of a flicking a marble with the tip of your thumb motion.
 
My 0551 was difficult to open and the lockbar was difficult to disengage. After having broken it in(that, or it broke ME in:D), I can easily flick it open and unlock it with no problems. The thumb nail might get a bit sore if I do it a lot, but other than that it's really not much harder to open and close than my Umnumzaan.
 
I handled one at my local knife ship (SRknives) and noticed it was a little bit difficult to open one handed as well. I figured from the videos and reviews that it would get loser with time. I would losen the pivot a bit, should fix your problem.
 
Update:

Well I "adjusted" the lockbar, after taking the the clip and Hinderer stabilizer off. Of course I over did it right off the bat and and then had some blade play from a weak lock-up. So, then I had to take the knife completely apart to bend the lockbar back. No real problems there, however, now I need to find some grease to lubricate the blade and washers. And, what is the proper way to install the washers? Does the "flat" side go on the blade or frame side?

Any ideas on which grease? I've heard some use Fluorinated grease, is that really necessary? I tried some DC4 silicone gel I had laying around and it doesn't work at all, actually made it worse. Blade is very sticky and dragging now with flat side of the washer towards the blade.


FlaMtnBkr,

Yeah, I'll try the new method on the other folders and see what happens. Very counter-intuitive pushing parallel and not perpendicular, at least to me.
 
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Harpoon1 said:
Update:

Well I "adjusted" the lockbar, after taking the the clip and Hinderer stabilizer off. Of course I over did it right off the bat and and then had some blade play from a weak lock-up. So, then I had to take the knife completely apart to bend the lockbar back. No real problems there, however, now I need to find some grease to lubricate the blade and washers. And, what is the proper way to install the washers? Does the "flat" side go on the blade or frame side?

Any ideas on which grease? I've heard some use Fluorinated grease, is that really necessary? I tried some DC4 silicone gel I had laying around and it doesn't work at all, actually made it worse. Blade is very sticky and dragging now with flat side of the washer towards the blade.


FlaMtnBkr,

Yeah, I'll try the new method on the other folders and see what happens. Very counter-intuitive pushing parallel and not perpendicular, at least to me.
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You get used to it, or you don't. Now that I think back on it, that may be why my coworker(also a knife nut) couldn't open the Umnumzaan. Pushing perpendicular will not do squat. Have to push straight up, and only slightly out. Feels perfectly natural to me now.
 
Never had a problem with my 0551, just keep index finger tip off lock bar and then push up, mine was a little stiff when new, after 2 months of carrying and opening and closing, it is smooth as glass now, mine is in 1300 serial number range, so it has gone through the refinement process as they made little tweaks to as production went on with the 0551, still a little hard to unlock, finger nail helps there.
 
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americanbulldog1 said:
I had the same problem with mine. I don't remember which post I saw it in but the issue was addressed in regards to opening technique. Instead of pushing outward, you push more upward then outward. Takes a little getting used to but works perfectly.
Click to expand...

So glad I found this thread! I got a 0550 yesterday and I've been tearing my thumb up trying to open it. Pushing primarily upward and keeping my other fingers off of the lock bar did the trick!



kat1 said:
Never had a problem with my 0551, just keep index finger tip off lock bar and then push up, mine was a little stiff when new, after 2 months of carrying and opening and closing, it is smooth as glass now, mine is in 1300 serial number range, so it has gone through the refinement process as they made little tweaks to as production went on with the 0551, still a little hard to unlock, finger nail helps there.
Click to expand...

Are the refinements/tweaks documented anywhere? I'm curious as to what has changed.
 
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