ZT 0452 lock up

[stabman]

when the lock goes to 100% engagement, does it require two hands to disengage?

That really depends on the particular model/knife.
On some of mine, it was the same effort as regular engagement.
On others, it was much more effort...on some, it took two hands.

 

[Scurvy092]

Crack is happening at the stop pin.

This is for reference, you can't see the crack here.

It's hard to see, but there is a crack that starts at the bottom of the hole, and goes up towards the top of the scale. On the top right side of the hole, there are some stress cracks from where a small layer of CF is peeling up.

Highlighted for clarity

Same crack from another angle, showing where it goes up the scale

Highlighted for clarity

Bought directly from ZT on 9/30/14, and was not this way out of the box. Knife was used and carried, but never dropped on any hard surface.

Interesting. I wonder if it's all the way through or just the top layer of resin spalling. Interested to see how it holds up.

F1 suspension control arms and push/pull rods are made from CF and they take FAR more shock and abuse over the course of a race than a typical knife would see in 10 lifetimes. I can't remember a part failing outside of a collision.

 

[Sonnydaze]

I think that a lockblade that moves THAT far over a tang is/can be a problem. It is unintended, I am sure. I've owned many models of ZT's and have not experienced that movement at all.
I got concerned reading this thread as my new ZT 0808 was due to come in today. No need to worry. It locks up at perhaps 30% and is solid...thumbpressure or not, and does Not stick. Love this 0808.
Sonnydaze

 

[kniferbro]

Never mind.

 

[insta9ves]

Interesting. I wonder if it's all the way through or just the top layer of resin spalling. Interested to see how it holds up.

F1 suspension control arms and push/pull rods are made from CF and they take FAR more shock and abuse over the course of a race than a typical knife would see in 10 lifetimes. I can't remember a part failing outside of a collision.

How the CF is formed into shape plays a big factor in its strength, not just the material itself. For CF in cars they are often layered in mold following the shape of the end product, instead of being machined from a solid block like a knife handle. The CF car parts usually already have the final form before they are being baked. The way they layer the CF ensures maximum strength in the area that take the most stress, and this is also why they are so expensive. I bet they could have easily milled the part from a solid block but it will be much weaker.

Check out this video where Koenigsegg showed how to make a CF wheel. You don't want to machine these:
https://www.youtube.com/watch?v=PGGiuaQwcd8

 

[palonej]

I have 3 ZTs all bought from Scott at USAmadeblade. I checked all 3, 450, 452cf and a 562cf not one of them will budge.
Joe

 

[ml311]

Recently purchased this knife and the lockup is solid, but when the blade is closed it moves a little front to back and rattles. It does not move side to side so I know it's not a loose pivot, so I think it's an issue with the location of the detent hole. This is my first ZT knife so I don't know if that's normal but from the reviews I expected better quality. I sent it back to ZT as defective and it was just returned to me still loose with no explanation. So far I'm extremely dissapointed with this knife and the warranty process. Just curious if the blade being loose in the closed position is actually a defect or if it's normal for this knife.

 

[Scurvy092]

At that price point, I don't think so. There are custom knives several times more expensive that can have this issue.

I would say it's more of a nuisance than a defect.

 

[sharp_edge]

No it is not normal. I have had multiple ZTs including this model and none of them is like that. Strange that your knife was returned to you as it was. ZT service is usually very good.

 

[Vicarious Reality]

My ZT 804 can be pushed all the way over by cutting in a scraping motion to the left; applying hand force to the lockbar, it also dented the tang a bit... only a corner is making contact...

None of my other Ti framelocks can be pushed even a little, and none of them require two hands to unlock when stuck

 

[dgf]

My 450 has no issue with over a month of pretty hard use

Sent from my SM-G925V using Tapatalk

 

[jill jackson]

The 0452 that had the bad lock slide, never did stop. I thought it was corrected at first by tightening the pivot, but with use it came back.

 

[sharp_edge]

So it is not because the pivot becomes loose?

 

[jill jackson]

Yeah, I thought it helped and there was so much distress caused by the mere mention of the lock moving so badly, I got caught up in wishful thinking. The 0452 never stopped sliding and I gave it to a friend at work. The 0562cf I have is rock solid though and other ZTs I own are too. So, it didn't sour me on the brand. In fact I just bought a 0909 that's extremely solid, even though it's a liner not a framelock.

 

[shinyedges]

The 0452 that had the bad lock slide, never did stop. I thought it was corrected at first by tightening the pivot, but with use it came back.

Then the pivot loosened up again, loctite?

 

[jill jackson]

Then the pivot loosened up again, loctite?

No, it never was the pivot. I thought it helped, but it didn't really. Just wishful thinking on my part. The lock kept skating across the tang face, with a bit of pressure. I just gave it to a friend who doesn't care about it. As the knife locks up fine otherwise.

 

[jill jackson]

I bought an 0804cf recently that does exactly the same as the 0452, I owned. Yep, the lock bar can be pushed with thumb pressure all the way across the blade tang face. The 0562cf has a solid lockup and won't bulge. Both , I've owned were like that.

 

[sharp_edge]

Jill - thanks for sharing. This is indeed worrysome. I suspect this happens more often with framelock with a steel lockbar insert than without. This of course is based on a small sample of (without an insert) an xm-18, kizer, zt0200 and (with an insert) zt0801, 0561, 0562, 0562cf, 0452cf, 0620cf, and Reate. None of the first three lockbars would travel noticeably when pushed, while 5 of the last 7 would, and 2 of these 5 would to the presentation side (again if pushed hard).

I could be wrong but it seems to me the blade tang face that mates with the lockbar is usually cut out more flat when an insert is present, whereas it is more sloped when an insert is not used. This natually will make it more difficult for the lockbar without an insert to move to the presentation side when pushed.

I am not necessarily saying the lockbar insert is a bad thing. It certainly can extend the wear and going with the above observation it may also reduce the chance of the lock being disengaged accidentally when force is applied to the blade spine (e.g. spine whacking).

 

[shinyedges]

I bought an 0804cf recently that does exactly the same as the 0452, I owned. Yep, the lock bar can be pushed with thumb pressure all the way across the blade tang face. The 0562cf has a solid lockup and won't bulge. Both , I've owned were like that.

Well you must like that then... considering you continually purchase them and push the lock bars over lol

If I didn't like something, I damn sure wouldn't continuously do it over and over again. I guess I'm just confused on why you keep purchasing zt framelocks and then intentionally forcing the lock bars over

 

[jill jackson]

I don't even know if it's really a defect at this point. The knives still lock up dead solid and flip to early lock up everytime. I'm not going to worry about it on the 0804, because the knife overall is very good.