ZT 550: Sent it in to KAI and now no detent?

jstn

jstn

Joined
Jun 27, 2012
Messages
3,737
I sent in my 550 a while back for vertical blade and got it back today. The blade play is gone and the knife is nice and sharp but a strange bi-product of the repair is that the detent is now really weak. Before, my favorite thing about the knife was the strong detent, but nowthe blade will flick out with out using the thumbstuds. I've tried adjusting hte pivot, and it makes it tighter, but then it won't really open properly.

Anyone have any advice on how to remedy this? I'm not complaining about KAI, they did fix the problem and in a timely manner. Just wondered if anyone else had experience with this. Thanks
 
Update:

After playing with my 550 a little tonight I decided I actually like it better since KAI worked on it. I couldn't quite place what the other difference was, and since I have been carrying my 560 lately it wasn't obvious at first, but since sending it in it now has a deep carry clip! I looked at some pics of the new 550's with deep carry and discovered that they replaced the entire Ti side of my knife with the new model!

The cut of the lockbar is quite different from the old ones, and after comparing it to my other old model 550, it is MUCH smoother. I am really happy with KAI, they hooked me up and I like the new version even better than the old 550. Anyone wanting a 550 I recommend getting the new deep carry version! Experiences like this are why I keep buying more ZT's and Kershaws than any other brand.
 
i'm sending in my ZT0550 today. vertical play. i have spent good amount of time trying to resolve the issue, and wasn't able to. last night i put a straight edge on top of the lock face and found out there is no way i'll be able to fix it. the lock face was not straight. i held off sending in my ZT0550 since i actually like the old clip and cut out on the inside.. hope i get same ti lock side back. the new clip and cut out side side look nice, but i really like the old clip.
 
I had to send my 0300 in a while back because the lock would fail regularly and I didn't feel like closing that monster on my hand. After a couple weeks i got it back and now the lock failures a cured, but now it has a very late lock up. It looks like they just ground the lock face a bit. Now it's pretty stiff to disengage the frame lock when closing.
 
bullet08, I bet if you make a note when you fill out the form to send it in to KAI they would be willing to give you one of the original Ti sides. I have a 551 so I'm pretty happy to have one of eash now. I wasn't crazy about the old clip but I did like the detent. This new version is so incredbily smooth though I can't help but like it, but I always have my 551 if I want the strong detent. Hope it works out well for you.
 
To fix vertical bladeplay in a framelock or linerlock there are two main fixes.

Fix 1 - replace the locking frame completely.
This is a radical thing to do but may well be the case as it is a factory knife and while I'm sure they don't just have spares lying about, this may well be the case. Ball detents need to be precise to work to their maximum potential and the longer lock required to stop the vertical play might mean the ball and detente don't line up 100%. The easiest way to tell would be to look at the track left by the ball running along the blade. It's normally pretty obvious if the track doesn't enter the hole at the right point but this would mean dismantling your knife and voiding the warranty.

Fix 2 - A slightly larger stop pin.
Normally it only takes a small amount of gap to create blade play and a slightly larger stop pin will fix this in a second. By far the easier of the two fixes. The easy way to tell if this is what they did is to check the spine in the open position. A larger stop pin will mean the blade locks up earlier and will not line up exactly with the back of the handle. If they tried to correct this by grinding down the anvil that the stop pin engages you'd be back to square one and there would be blade play. The side effect is that the larger pin forces the blade into a slightly more open position when closed. The ball detente parts will be aligned well butit will only *just* be catching the lip of the hole. If this is the case, you could fix it quickly with a dremmel by grinding tiny bits off at a time inside the curve the stop pin nests in. Again, you'd be kissing your warranty goodbye.

As long as it's not a danger and opening accidentally I'd shrug it off. If you're still concerned, maybe fire it back again. I've heard nought but good about the bunch at KAI, they'll see you right.
 
i would just email or call them and ask about it and see if you can fix it or if it needs to be sent back
 
Gareth Bull said:
It's normally pretty obvious if the track doesn't enter the hole at the right point but this would mean dismantling your knife and voiding the warranty
Click to expand...

Dismantling your Zt or kershaw does not void your warranty in any way
 
nwmetalbug said:
The 0550-0560 doesnt use a stop pin the thumb studs are the stops
Click to expand...

I looked up the model after posting, you're spot on. The fixes I mentioned still give the general idea of how vertical blade play is overcome but for the sake of accuracy I'll make the terms broader.:rolleyes:

To remove vertical blade play at least one of the stopping features has to get bigger. Be it the blade, the lockbar or whatever the knife uses as a stop pin arrangement. It's likely this will have a ripple effect on other functions in the knife.
They may well have replaced the blade thus leading to a one or a combination of the two likely causes I mentioned indicative of a weak ball detent. In the closed position the thumb lugs don't touch the handle so there is a stop pin for this position. The OP could check the run of the ball by dismantling the knife (also check how much of the ball is sticking out the lock while you have it apart). A slightly more advanced closed position might just be the cure.
 
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i think only solution to my 550 is to replace the frame side. i took a look at the lock face night before sending it in. the thing was rounded so much towards the front, it will rock on the lock face unless it's wedged tight into the blade tang. i know this is brand new knife, but i also found strange cuts and scratches around the lock face. i'll wait and see what happens.
 
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