Failing lock on Cara Cara and Manix

[Rob]

Hi folks!

Vincents thread got me wondering and just out of curiosity I tried to spine-whack my Cara Cara which is my EDC since a couple of weeks now. The result can be seen H E R E

The lock of this knife failed very easy, I didn't even had to whack it hard. Because of that I tried to place the spine on a cutting board and apply pressure. T H I S is the result.

Somehow scary, isn't it? This one went out of my pocket immediately but before I replaced it with my (until now) trusty Manix, I spine whacked this one too - just to be sure. Look H E R E. Now I don't know what to say. It was indeed harder to make it fail but it did fail. The only positive thing about this is that I couldn't make it close by just applying pressure on the spine like the Byrd.

After filming everything and viewing the footage, I first thought that I maybe touched the lockbar by accident so I tested it again by holding the knives at the end of the handle to prevent this. Same result, but I was too lazy to film that too :rolleyes:

OK, a failing knife that was produced in China, but the Manix?!? :eek:

Could anyone who owns a Cara Cara spinewhack it and tell me how it performs? Also opinions on the Manix are appreciated.

Cheers, Rob

[Gerard Breuker]

I just stopped spinewhacking my Manix because I didn't want to ruin the cutting board any further but the lock held fine.
I must admit I find it difficult to see the actual moment the lock fails on the movie you posted so maybe my spinewhacking is different from yours but I couldn't get the lock to fail.

[Rob]

Yeah, I know the quality of the videos is a bit crappy :o
I try to get a better shot later this day. Now I'm off to the university for a lecture :rolleyes:

Cheers, Rob

[Vincent]

I opened a can of worms here. But I think its good and samthing Sal and eric may want to take into consideration.

Rob if you are taking the video with a digital camera, try to up the quality or frames per second as this will show the entire footage.

I can understand the cara Cara failing but not the manix.

I can say one thing, the Compression lock will not fail. The handle would break or the pibot would break. Just a well desighed and strong lock.


Rob watch my videos for a safer way to spine whack, Even with the gloves you dont wnat to be bitten.

[ront]

What is it with all of this spinewhacking that is going on? I guess I fail to see the point . Should we all be doing this to all of our knives to make sure that we recieved a quality product? I am thinking not.

Ron

[Michael Cook]

What is it with all of this spinewhacking that is going on? I guess I fail to see the point . Should we all be doing this to all of our knives to make sure that we recieved a quality product? I am thinking not.

Ron

:spyder: I'm glad my MBC doesn't call for snapping back cuts! I'm still more concerned with my grip failing before the lock! I'm sure we'll soon be hearing all over the internet about back locks not being reliable with this and the threads at blade forums. :spyder:

[Gerard Breuker]

What is it with all of this spinewhacking that is going on? I guess I fail to see the point.

The point is that it is better to test the lock on the folders you use beforehand than finding out the lock will fail in a way that involves blood or worse.
As pointed out in another thread lock failure can happen this way during normal use and it is better to be safe than sorry.

[saracen]

After watching Vincent's video's last night I deciced to do a bit of spine whacking myself for my own piece of mind, first up was my CRKT Tigh Tac, a nice simple liner lock, inexpensive, thought i'd practice/ warm up with it on the bread board.. lot's of whack's, more whack's then some really hard one's for good measure, 'cause it was holding up fine, whacked it some more and ultimately was impressed, it never flinched and functioned flawlessly as before.

Next I grabbed one of my Dodo's, reading many expierience's of problems with the ball lock and having previously tried to force a failiure and not done so was interested to know if it would stand the same treatment.. which it did, no problem at all, finally I gave my Millie a go which to be honest I did not expect to bother it at all and am pleased to say it suffered nothing for my curiosity, I know some poeple hate the liner on the Millie but I have found it in use to be just fine and that includes cutting/rocking it up and down through some very dense plastic and rubber.

[ront]

I think if it was really any kind of a problem, we would be hearing reports of cut fingers all over the place. I am sure there are a few knives that will fail here and there, but most will never be asked to stand up to the stress that a good spinewhacking is appling to the knife!

Ron

[skcusloa]

When someone brought up their failing manix and chinook, Sal dropped in. He encouraged people to check. He told the guy to send it in with "Attention Sal" on the box so he could personally look at it. He didn't even have a video.

I only have 2 lock backs right now. I just whacked the calypso hard enough to put dents in the wood, no fail. I just got my byrd to fail with just pushing it with my hand. It's a very small knife though. I'm not worried about the byrd. It's like worrying about a jester failing.

[HoB]

Well, I think in principle a lockback is a very strong and reliable design. Even though this is probably dangerous to say, most engineers would probably guess a lockback to have an ultimative strength many times larger than that of a liner, simply because the bar is under tension while it is under compression in a linerlock. In civil engineering steel and concrete are often combined because steel is very stong under tension but weak in compression while concrete has the opposite properties.

The only problem I can see is when the lockbar doesn't engage sufficiently and slips out of the notch upon impact. This was clearly the problem with my Manix. The good thing is though: If the lockback holds up once, it will always hold up. If the lockbar fully engages I don't see how this lock would fail (aside from being cruded up with lint of course).

As to the purpose of the spine whacks: When my Manix failed the first time, it didn't take THAT hard of a whack. Sure it was a hard snap out of the wrist (otherwise I would have noticed it much earlier) but not a full arm swing. An impact like that could easily happen if you are clumsy and catch the edge of a kitchen table or counter with the blade coming from an arm position below the table in an upwards motion. This type of accident has even a name among butchers it is that common in the professional food services (I forgot the name but it is meantioned in Juranich's book).

But this all brings back the discussion about the Boye dent. The difference between failure and "no-way-I-could-make-this-fail" was about 1/200 of an inch (at the notch, about 3/100 on the release side of the lever)! That means that even a small depression of the lockbar can potentially weaken the lock substantially. All aestetics aside, it makes me question why not all lockbacks have a Boye dent just for "insurance purposes"?

[Crafft]

Just did some spinewhacks (for some piece of mind) with my Chinook II pe and Manix ce. I'm glad they came out OK!!
Only our wooden cuttingboard is seriously dented now :D

If all of us (who dare) do some testing with those MBC rated locks than we could establish if it could be something structural. Hope not though!!

[STR]

Not to sound distrusting or anything but I'd feel better if I were able to see the whole knife and not just the blade when these tests are done. I'd like to see the postition of your hand in relation to the lock release personally.

[Chucula]

i just banged around my manix. hit it at the middle and near the handle, many differnet angles, did not have failure. maybe it requires a certain whip or something but i hit pretty hard. perhaps bladeplay has a role in how easily the lock fails

[ghostrider]

Rob,
I just tested my Cara Cara (sorry, no video). I gave it about five wacks, and used as much force as I could without loosing hold of the knife. No failure. When I turned it over and forced the cutting edge into the cutting board, I did notice a slight amount of vertical play, but not much.

I also tested my Caly Jr. grey. This knife has the same problem that Vinny’s Caly Jr. grey had. A small amount of force on the cutting edge will completely disengage the lock bar. After a few wacks with the Caly Jr., no failure.

[ghostrider]

Not to sound distrusting or anything but I'd feel better if I were able to see the whole knife and not just the blade when these tests are done. I'd like to see the postition of your hand in relation to the lock release personally.

I have to agree with STR. That was the first thing that I thought of when I watched the videos. In them, it looked as if the knife closed without even being struck upon the board. It was as if the motion of "flipping" them upward before comming down on the board, caused the momentum to close them.

[Vincent]

I hope my videos were clear and detailed eneogh for you guys.

[Rob]

OK, I just wanted to film the spinewhack of the Manix again so that you all can see it a little bit better. Taking photos is fairly easy but I really suck (my digicam too) at making movies... Anyway, I was mounting the camera on the tripod, put everything in place, grabbed the Manix and opened it. Now the most strange thing that I ever wittnessed happened: The lockbar broke! :eek: :mad: AAAAAARGH!!!

I suspected the lockbar not being like it should be after THIS problem I had last year but after that also rather strange incident it behaved totally normal so I didn't think about it anymore.

I always thought that this knife is one of the best knives that Spyderco ever produced, I carried it for 10 months every day and really enjoyed using it - now it's gone

At least there are two good sides of this: 1st it did not happen while I was using the knife (thank god!) and 2nd is that we now know that the tiny pivot can take more than the lockbar

Now I'll try to contact W&R, maybe they can fix it (hope so). If not I'm going to take a piece of Ti and make a copy of the lockbar myself. Should be difficult to break a 4 mm piece of Ti

Cheers, Rob

P.S. Oh, some pics of my destroyed companion...

[Rob]

Oh I forgot... for all the sceptics out there: here's another version of the Cara Cara-whack.

That's what I also did with the Manix. On the first videos I just grabbed the knives more firm and a little bit more at the center of the handle - just before the lockbar. The result is the same.

An for all the suspicious out there: No I am not saying that lockbacks are bad, no I am not saying they fail more often than other locks, no I am not saying Spyderco is a bad company and NO I did not break my favourite knife intentionally.

Cheers, Rob

[CopilotATS-55]

:eek: :eek: :eek: :eek: :eek: :spyder: