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Can't open my ZT 550!

Murindo

Gold Member
Joined
Jul 4, 2010
Messages
1,999
I have a new ZT550 and cannot open the knife one handed using the thumbstud. I'm to the point where I'm going to have to sell it or trade it. Any suggestions?
 
Mine was like that when I got it. I just opened and closed it A LOT until the detent got better. I'm sure some people here will suggest you modify the detent, or send it back to ZT.
 
Make sure you are holding it in a way that you are putting no pressure at all on the lockbar. It is a little tricky at first, but once you get the hang of your finger placement it will fly open.
 
Make sure you are holding it in a way that you are putting no pressure at all on the lockbar. It is a little tricky at first, but once you get the hang of your finger placement it will fly open.

^^^^^ This. It makes a BIG difference and is one reason why I generally prefer liner locks to frame locks.
 
If you can open it with your left hand, then your technique is wrong when opening it with your right.
 
Adjust the pivot screw a little, using the correct tool of course to avoid stripping the head.
Check your grip on the knife, don't press the lock bar closed while trying to open the knife.
Baring no success with that, i'd say try a flipper.
 
I'm in the same boat and haven't really figured this one out -- my 0550 is easy to flick open, but I can't open it slowly with one hand. I'm liking mine, so guess I'll just have to be satisfied with flicking or two handing open. Let me know if there is some secret technique I haven't found!
 
Almost willing to bet you problem is just technique. Push the thumb stud FORWARD vs. out and don't put pressure on the lockbar. I had the same problem with my 0551- once I got the hang of it though the thing flies open :thumbup:
 
When you say that you can't open it with one hand, are you talking about fast or slow opening? I'd mostly agree with a combination of the suggested answers: pressing in the lockbar, thumb placement and direction of push, and then just plain breaking it in. I'm not sure what kind of experience you have with studs, but for a fast opening, I use a motion similar to flipping a coin: thumb builds tension (with a coin, tension is built up against the finger, with a knife, tension is built up against the stud and detent) then flick! I got a Blur that I removed the assist from and I couldn't open it easily for a few days, even with the right technique, which just meant it needed to be broken in.
 
It's probably my technique and I must be putting some pressure on the lockbar, though I don't have this problem with any other thumbstud framelocks. It flips fast and easy, but I can't open it slow. Once it breaks detente it flies open. I've been trying different grips, and have managed to flick it halfway open then slowly open the rest of the way. It doesn't bother me - I flick it open most of the time anyway.

Is this the same problem you're having Murindo?
 
When I got my 0550 I could not open it one handed either.
I put some Super Lube on the detent and after cycling it maybe a few hundred times it would then flick open very easily.

I am left handed and it is very easy to open that way.
Now as others have said even the slightest amount of pressure on the lock bar will make it a bear to open so opening it right handed takes a bit of practice.

I too was about to give up on it at first but now it is one of my favorite knives.
 
Is it brand new? If so it probably just needs some time to break in, mine was very difficult to open when I first got it but after about a week of use it loosened right up.
 
I used my index finger and my thumb. That gave my index finger a place to rest that didn't put pressure on the lock bar. I traded it away though on a Gayle Bradley. It was the weirdest detent. It was hard to open one handed but you could shake the blade open as well.
 
Thanks for all the tips. I can thumb flick it open right handed and slow open it left handed but there is no way I'm going to learn to open it slowly right handed tip up. However, changing the clip to tip down right side carry keeps my finger tips off the lock bar. Problem solved!
 
Had same problem. Adjusted my grip to hold knife closer to the rear end and pushed more up and out than directly out. Also removed all fingers from touching the lockbar. Still tough to open......but can open.
 
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