does lockbar thickness really matter?

[RubiconSS]

Good thread, I've never had one fail. I guess I can imagine what the outcome would be. Maybe I've been trusting them too much.

 

[STR]

Good thread, I've never had one fail. I guess I can imagine what the outcome would be. Maybe I've been trusting them too much.

This is true with any folder. The frame locks and liner locks work very well for lots of people. Millions I'd say. Any moving parts mechanism can fail thats a given. I think mostly so long as people use their knives with common sense that they are going to be fine. Just be sure to buy quality items. By quality I mean tried and true well reviewed models from trusted makers/manufacturers. Kershaw, Spyderco, Benchmade and so on you know? Those are all going to bat high averages insuring you get a good one no matter which you buy and if you don't most importantly they back it up and fix it!

STR

 

[Thomas W]

My theory as to why you don't see a lot more lock failures is the fact that a significant portion of these hard use titanium folders are safe queens or pocket queens not really seeing any kinda of use.

This is not a theory, it's an opinion. Another opinion could be that you don't see too many of these lock failures because they actually work, work well, and don't fail at the rate your alluding to.

I'd also like a link pointing towards the "fact" that a significant portion of all of these knives sold end up in underwear drawers.

Kai USA produces a lot of frame locks, some more burly than others. We have a warranty department, a lot of knives that come back are used...heavily. A very, very, very small percentage of these frame locks that come back, come back because of a faulty lock. Being a betting man, I'd give odds that this is the case with most brand name manufacturers that produce in this genre. Perhaps this is more telling than the above, perhaps not.

I'd like to say here that it is very easy to draw a conclusion, generalize, and define whatever we are discussing, in this case frame/liner locks, based on your own experiences. Unfortunately this tells only a small tale of the big story. We should all keep that in mind. Opinions are not facts, nor should poster lead members on in their views direction. There are anomalies that can go against the norm's grain almost every time. To exploit them, or make them more than reality is slightly irresponsible.

I'll add that I can only speak from the place where I'm at, and don't speak for any brand(s) other than our own.

 

[Professor]

A very insightful post as usual, STR, thank you.

The qualities of CRK's blade tang ramp/lockbar face interface have always interested me. I once asked Chris years ago about the interface, specifically the angle of the interface, as it bothered me that I could push the lockbar all the way to 100% on my small Sebenza to the point that it contacted the opposite ti slab. I'd had other framelocks with a dramatic interface angle where doing this would be very difficult to next to impossible.

Chris told me that the Seb's interface angle lends itself to lesser possibility of accidental lockup disengagement first and foremost, and that when you death-grip a Sebenza and the lockbar travels all the way over, it is in fact a purposeful and by-design buckling of the ti that's occuring at the twin cutouts (pertinent to this discussion).

Still, it drove me crazy that I could push that lockbar all the way over, for fear of premature wear. However, after just under 9 solid years of EDC, I've never worn out my Seb, and never had the lock fail under duress.

Great thread!

Professor.

 

[Artfully Martial]

Ah, the point of the thread wasn't to concern people over the reliability of the lock, it was to clarify what, in particular, thickness affects in terms of liner/framelock strength and reliability.

I have no doubt that any quality made "crosslock" will be plenty tough for any ordinary user. Indeed, if one were to go back to the time when dinosaurs ruled the earth (2005) you'd see that I did a lot of testing on liner locks when I first got here--that's actually how I got started on bladeforums. At the time, it was prevailing opinion that liner locks were death sentences but framelocks were invincible. So I did some rather ghastly testing on my cheap old CRKT m16 to prove my point and I think I was successful. The lock did warp, but it never failed or came close to failing. I got a lot of hell for that back then.

I can tell you that I, personally, use every single knife I have, no matter the expense or rarity (granted, none of mine are worth more than $300). That said, I never abuse a folder. I use them for cutting, and generally that's just boxes and such. So my 0302, 0400 and 0500 are probably superfluous. I have some serious FBs for chopping etc.

As per Thomas W's words of wisdom, it is technically true that he can "only" speak for Kai, but in my opinion, Zero Tolerance is probably the dominant force in liner and framelock production right now, so that alone speaks for a lot. In fact, I believe that every ti framelock I've ever owned was from Kershaw/ZT and they were all perfect (Blue Bump, Ti Tyrade and ZT0302). At least in regards to the Blue Bump and Ti Tyrade, I prefer that framelock to the Sebenzas I've played with.

 

[RubiconSS]

It's a common understanding in the knife side of the world that the thicker the lockbar (be it liner or framelock) the better. But I don't this is quite so obvious.

In particular, lockbar thickness as a criteria is ambiguous. Where does the thickness matter? The interface with the tang? The cut out? Average thickness?

If we assume it's the interface, then is the thickness simply wasted in knives with early lockup (that's the vast majority of folders)?

If we look to the bar itself for thickness, ignoring the percentage lockup with the tang, perhaps it makes more sense. But what about the cut out? It seems like the cut out would be the obvious point of failure, and it is, by definition, the thinner part of the lockbar. And if this is so, why don't we much variation in cut out thickness?

If the weak spot is the cut out, why not reinforce that area? Put its back against the g10 scale for instance, instead, as is common, letting the cutout face the scale. Or can we fill in the gap with g10 on a 3d machine scale to reinforce it?

At any rate, assuming that lockbar thickness is a crucial factor in lock integrity, what does that actually mean? That's the central question here.

When the discussion is Knives and I read these words I do not see the discussion of failure or safety as a huge leap.
I said and I still think it is a great thread and one that will undoubtedly draw a plethora of insight and expert opinion. Central to the discussion however will be the under pinnings relating to the ultimate question - Engineering (thickness, angle, cutout placement and design) to minimize if not prevent failure.

 

[Noctis3880]

Actually having given it more thought and playing with the liner lock on my Buck Vantage Pro, I would have to say that the thickness only matters in a very select few situations. The Vantage Pro liner lock is thinner than my Emerson liner, but the lock hasn't moved any closer to the right side of the handles in recent months, there is little if any blade play, and spine whacks will not disengage the lock.

The issue I have with my Emerson would have more to due with the liner lock material rather than the thickness. The wear would have been much slower had stainless steel been used rather than titanium, but even so I wouldn't expect the lock to actually fail unless you really abuse the knife, and I had full-on slammed the tanto blade of my CQC-7 into a wooden pallet:thumbup:.

Thickness would just contribute to better wear and endurance of the lock. But again, I think even a knife with the weakest and thinnest locking liner won't fail unless you use the knife for something a knife was never designed to do.

That being said, I have no complaints about the monstrously thick framelock on my ZT 0551.

 

[JNewell]

Thomas, thanks for the insight into what goes on where the rubber meets the road (i.e., the warranty/repair process). That's interesting and useful data, even if it only applies with certainty at KAI.

This is not a theory, it's an opinion. Another opinion could be that you don't see too many of these lock failures because they actually work, work well, and don't fail at the rate your alluding to.

I'd also like a link pointing towards the "fact" that a significant portion of all of these knives sold end up in underwear drawers.

Kai USA produces a lot of frame locks, some more burly than others. We have a warranty department, a lot of knives that come back are used...heavily. A very, very, very small percentage of these frame locks that come back, come back because of a faulty lock. Being a betting man, I'd give odds that this is the case with most brand name manufacturers that produce in this genre. Perhaps this is more telling than the above, perhaps not.

I'd like to say here that it is very easy to draw a conclusion, generalize, and define whatever we are discussing, in this case frame/liner locks, based on your own experiences. Unfortunately this tells only a small tale of the big story. We should all keep that in mind. Opinions are not facts, nor should poster lead members on in their views direction. There are anomalies that can go against the norm's grain almost every time. To exploit them, or make them more than reality is slightly irresponsible.

I'll add that I can only speak from the place where I'm at, and don't speak for any brand(s) other than our own.

 

[MikeC]

Thomas, I didn't say anything about kershaw or zero tolerance so why don't u chill out. Moreover I didn't say anything I was suggesting was fact it was my own theory. I'm not the first person on here to suggest that a lot of these highend hard use knives don't actually see that much use. Also I kinda mentioned the fact that these locks seem to work ok and gave my opion as to why and finally again I nor anyone else touched upon u personally r ur Kai products yet u went on the defensive about ur stuff. My bad for not using opinion And using theory. I can tell u one thing it sill be a cold day in he'll before I ever buy any Kai products. For the record most of my info comes from str either his post or through numerous personal phone calls I've had with him.

 

[Thomas W]

Thomas, I didn't say anything about kershaw or zero tolerance so why don't u chill out. Moreover I didn't say anything I was suggesting was fact it was my own theory. I'm not the first person on here to suggest that a lot of these highend hard use knives don't actually see that much use. Also I kinda mentioned the fact that these locks seem to work ok and gave my opion as to why and finally again I nor anyone else touched upon u personally r ur Kai products yet u went on the defensive about ur stuff. My bad for not using opinion And using theory. I can tell u one thing it sill be a cold day in he'll before I ever buy any Kai products. For the record most of my info comes from str either his post or through numerous personal phone calls I've had with him.

MikeC,
I'm chillin, really I am. I'm unsure why you're so upset, so upset that it'll be "a cold day in hell" before you ever buy a Kai product again.
If you're above being corrected for some wordage you've posted, sorry, I was just pointing out that it was wrong. No need to get all hurt about it. I'll be more tender from here forward.

I spoke with STR on phone today myself, quite a gentleman if I say so myself. You've got good council there MikeC. :thumbup:

Truly General is an odd place of which I swear more peeps get their feelers hurt by me.
Missed that vacation over the Holidays so I'll look to take a break from the forums for a while now, seems it'll be for the best.

 

[Toyz]

To the OP I have never had a frame lock fail on me, but in all honesty I do not "abuse" my knives. Hopefully one of these days when I am at a knife show I get so handle one that has no relief cuts in them - I am anxious to see how much more effort is required to disengage.

Thomas - speaking for myself - I respect when you and others from the knife world give your insights, as you get to see so much more than many of us do. Design, collaborations, R&D, manufacturing and service - I'd love to be involved in that industry. A lot of what I have learned from my times on the forums has been from people from the industry like yourself, whether a larger company or a one person custom knife maker.

Hope you don't vacation for too long.