Zero Tolerance 0561 Crack

[diavic]

Last night I noticed what I thought was a hair or a scratch on my ZT 0561. After further inspection I realized it was a crack. It cracked between the stud stop and the jimping.

Its disappointing but I'm sure ZT will take care of it.

 

[Dean C.]

I have heard of this problem before, that particular area comes under allot of stress due to the thumb studs acting as a stop pin for the blade as well (much like the Strider design). From the reports I have read about ZT will fix your knife no problem so no worries there. The one time I had to use their warranty (for a 0454 no less) they took great care of the knife and it was returned quickly.

 

[danielocean03]

ZT (KAI) has a top-notch warranty and excellent customer service as well. You shouldn't have any issues getting that taken care of. Just fill out their form and send it in.

Link to their form: https://zt.kaiusaltd.com/warranty/form

 

[diavic]

I shipped it off this afternoon. Hopefully it won't take 6 weeks.

 

[diavic]

I got my knife back last week. Turn around time was about 2.5 wks. They replaced the blade and added a hardened insert to the frame lock.

They also put the original serial number on the new blade. This surprised me. I had always heard that the replacement blades have no markings.

 

[Gabriel]

Very cool.

 

[danielocean03]

Good to hear.

 

[diavic]

I noticed this wkend that the blade has cracked again in the same place. I guess it will be going back. I may see if they will replace it with a different model. I don't really want to keep sending this in every couple of months.

 

[glock212327]

Pictures? I am interested to see what this looks like I have a 0561 hope mine doesn't do the same. Good luck with repair #2

 

[diavic]

Pictures? I am interested to see what this looks like I have a 0561 hope mine doesn't do the same. Good luck with repair #2

Well I'm not very confident in the 0561 now

 

[rhino]

Well I'm not very confident in the 0561 now

View attachment 50697

Hmmm . . .

It would be interesting to compare your frame to another ZT0561 side by side. It's possible that yours is out of spec where the blade stop/thumb stud meets it and it's hitting harder than it should. It still shouldn't crack like that, but I'm curious why you'd get identical blade cracks.

 

[glock212327]

That sucks. I know that ZT will take care of it but it shouldn't have taken two times. Let us know what they say and the outcome.

 

[diavic]

Hmmm . . .

It would be interesting to compare your frame to another ZT0561 side by side. It's possible that yours is out of spec where the blade stop/thumb stud meets it and it's hitting harder than it should. It still shouldn't crack like that, but I'm curious why you'd get identical blade cracks.

The stud is hitting only on the steel liner side. I don't know if this is intended. I think it would be hard to get even stud engagement on a production knife.

 

[diavic]

Update. ZT is sending me a prepaid UPS shipping label. They said they will need to evaluate the knife, but they might be able to make an exception for an exchange. I asked if it could be replaced with a 0562CF.

 

[Bradsknives]

The stud is hitting only on the steel liner side. I don't know if this is intended. I think it would be hard to get even stud engagement on a production knife.

The "studs" are actually the blade stop pins on this model. They are designed to hit the titanium framelock side (backside) and/or the titanium liner & G-10 on the front side stopping the blade in the proper position so the framelock will engage properly. They take a lot of abuse especially when you are flipping the blade open hard. Obviously some of the energy does transfer to the blade.

 

[rhino]

The "studs" are actually the blade stop pins on this model. They are designed to hit the titanium framelock side (backside) and the titanium liner & G-10 on the front side stopping the blade in the proper position so the framelock will engage properly. They take a lot of abuse especially when you are flipping the blade open hard. Obviously some of the energy does transfer to the blade.

That's where I would concentrate my analysis were I investigating this case!

 

[other dave]

Update. ZT is sending me a prepaid UPS shipping label. They said they will need to evaluate the knife, but they might be able to make an exception for an exchange. I asked if it could be replaced with a 0562CF.

Hope they don't lose it! https://www.indianagunowners.com/forums/cutting-edge/405011-attention-zero-tolerance-owners.html

 

[Bradsknives]

That's where I would concentrate my analysis were I investigating this case!

The cracked blade issue is not uncommon. It has been known to happen on the 0560, 0561, and 0562CF models. KAI has stated this happens due to improperly fitted blade stop pin. Personally I have a hard time believing that is the cause. I'm more inclined to believe that it is inherent in the design due to the frequency of this issue/problem. Could it be that the blade stock is to thin to take the abuse in the area where the stop pin is mounted?

 

[rhino]

The cracked blade issue is not uncommon. It has been known to happen on the 0560, 0561, and 0562CF models. KAI has stated this happens due to improperly fitted blade stop pin. Personally I have a hard time believing that is the cause. I'm more inclined to believe that it is inherent in the design due to the frequency of this issue/problem. Could it be that the blade stock is to thin to take the abuse in the area where the stop pin is mounted?

It's plausible that their explanation is correct and that it an inherent problem in the design. If the design is such that a virtually undetectable error in fitting or locating that part cause this failure, there is a problem with the design. It could also be compounded by the Elmax being a little too hard in that spot, and thus brittle and prone to crack propagation. It could also be someone failing to debur and otherwise remove any stress risers from the hole into which the stop pin is pressed. Let's say there is a small nick in the radius of that hole, you press fit a pin that just a tad oversized, thus pre-stressing that spot. Then you whack it repeatedly by flipping the knife open (as it's designed to be done), you could make that crack.

 

[Bradsknives]

It's plausible that their explanation is correct and that it an inherent problem in the design. If the design is such that a virtually undetectable error in fitting or locating that part cause this failure, there is a problem with the design. It could also be compounded by the Elmax being a little too hard in that spot, and thus brittle and prone to crack propagation. It could also be someone failing to debur and otherwise remove any stress risers from the hole into which the stop pin is pressed. Let's say there is a small nick in the radius of that hole, you press fit a pin that just a tad oversized, thus pre-stressing that spot. Then you whack it repeatedly by flipping the knife open (as it's designed to be done), you could make that crack.

Based on what KAI has said about the cause of this issue/problem, it make sense that this could be the reason.