Framelock lockbar travel?

robgmn said:
Unless it causes difficulty in unlocking, I don't see full lockup as a bad thing.
From an engineering standpoint, the more metal-to-metal contact, the more positive the lock.
Click to expand...

Yes... some of mine were worse than others. Some just required a little more effort and then a *pop* and it was unlocked, not a big deal.

Others got really stuck, like the 0452. That was a problem. But one fault on an other wise AMAZING knife :)

I'll also note that the travel never presented a reliability issue. If anything it made the lock more secure, it was just annoying having to unlock it.
 
I don't have the 0452 any longer, gave it away to a friend that didn't care about the lockup. Just got the 0804 and I am planning to ask ZT about the issue soon. Not even sure if it's considered a defect by them. After all the lock only gets tighter. It can't unlock and I've read some people's reviews that considered lock bar travel tighter to be a good thing not bad?
 
Jill, that 0804 looks to me to have an angled lock face. Are my eyes playing tricks or does it just not have as much as your other knives? I looked at my 0804 and it has an angled lock face and doesn't move over much at all with pressure in the locked direction.

I assume from the way the thread has progressed that the knives in question are likely Ti framelocks with a steel insert?

From what I've read about a book describing liner lock construction by Michael Walker who invented the liner lock, the blade lock face should have an angle of 7-8 degrees. Any less and the lock can wear quickly and travel all the way across like mentioned here, and more can cause lock rock and a lock bar that wants to push over and potentially unlock. Since a frame lock is essentially a liner lock without a decorative scale, which I can't see how Chris Reeve got a patent for, much less praise and acknowledgment for the frame lock 'creation', and most makers follow this same rule of a 7-8 degree lock face as stated by a few custom makers on forums and observed on actual frame lock knives. So if someone has a knife with a lock face that is cut straight across I would think there was a manufacturing defect or much worse, a bad design.

Anyways, all this is why I don't like frame and liner lock knives much. They need to be made just right and very small changes can greatly effect function, strength, and reliability. And you can have 2 knives of the same model and one knife can work fine and the other has problems or even fails. I have multiple fail and as a mechanical engineer I see the design as a bunch of compromises. For a light use knife that is used like a slipjoint it is probably fine. But trying to make a heavy duty knife to beat on and do things a knife shouldn't be used for, I personally don't see it as a very good design especially if you have to beef it up and oversize parts. But they have become popular for some reason. I feel like the lock was originally used when the patent expired because it was one of the few options for a lock and picked up steam from there. I would think licensing a different lock would be a better option but consumers line up to buy them so nothing will change while that still happens. I really don't see the desire to use them with a flipper since the detent has to be tuned and made just right and it's even a well known fact. Where other locks are much easier to adjust with different springs or longer contact with spring pressure. My best flipper is a Kershaw RAM that uses the HAWK lock. It opens effortlessly and reliably and similar locks that are held closed with spring pressure should also make great flippers with no need for 'tuning'.

I'll get off my soapbox and end my rant.
 
jill jackson said:
I don't have the 0452 any longer, gave it away to a friend that didn't care about the lockup. Just got the 0804 and I am planning to ask ZT about the issue soon. Not even sure if it's considered a defect by them. After all the lock only gets tighter. It can't unlock and I've read some people's reviews that considered lock bar travel tighter to be a good thing not bad?
Click to expand...

Hey Jill!
If the lock bar movement made un locking next to impossible,
Joewithout a tool of some sort, I would hope ZT would consider it a problem.
 
No problem unlocking the 804 with my thumb after pushing the bar over. No problem with the 0452 either. And neither went over so far they'd unlock the opposite direction.
 
I bought my 0452 pretty much LNIB off the Exchange a year or so ago. I had heard of the "over-locking" issue when I was looking to buy and had queried the seller about that while negotiating the purchase. I also asked about the detent, as I'd heard some were so strong as to make the knife all but un-openable. The seller reported that neither was the case, so I completed the purchase.

Upon receipt, I found the detent to be ridiculously hard to the point that it took an odd too-handed grip to flip the blade out. The detent did wear in after a thousand or so flips and it works just great now. I could, however, press the lock-bar into a too-far position that initially required a tool to pry it back, later two hands, and eventually got to the point that it could be forced a bit too far, though only deliberately, but could be unlocked by thumb only.

Looking at my knife now I can see that the locking face of the blade-tang is milled concavely. It seems likely this is done to afford a more non-slip interface while at the same time combatting the tendency of a low-angled locking ramp to wear more quickly. Such a grind would allow the lock-bar to be fairly easily forced just a taste up the steeper part of the ramp where it would gall just enough to "freeze' it in place. As my knife has worn in, and as stated above, this "over-locking" can only be achieved deliberately.

Looking at Jill's close-ups above, it would appear that her knife's lock-ramp is milled concavely as is my 0452, the angle away from the lock-side being far too steep for proper engagement. I wonder what the long-term-wear ramifications of this design are. Will the ramp wear begin to wear a bit of a shoulder, resulting in lock-rock. or will the lock-bar insert begin to wear a bit of an angle affording a greater chance for slippage? With so many knives in my "arsenal" I wonder if I'll ever get to that point.

I'm curious about my other ZTs now and will go have a look.
 
It's curious to me, that my ZT 0562cf has a much more solid nearly unmovable lockup. You sort would think ZT would know about what lockup they send their knives out with and would have more consistency.
 
Just checked my 0562cf and I can get it to move slightly. Enough to create a bit of lock stick, but no further.
 
I'm just hanging out playing with knives, so I decided to try out some of my framelocks. Some of them would not budge (at least with the force I dare contribute) beyond the small point it landed from normal opening. They were the ZT 452, 562, 808 and little Boker Plus Nano.

Most all my frame locks land between 40% and 60%. Many would move most of the way over, but only with what I would consider extreme force for that area of the lock. Including the ZT's 561, 801, 804 and 456.

The small Kershaw Onions (Leek, Scallion, Chive), and my ZT 450 moved all the way over with fairly light force. Was totally expected on the Kershaw's. And not really shocking for the 450 as I consider it a lighter duty Gentleman's knife.

There were two that would move from 50% to 80%, but would not budge beyond that. They were the Spyderco Domino and Kizer Ki3452. The Domino has an integral stop/over travel bar, and the Kizer has none. Well, at least no lock insert. Over travel is restricted by the g10 inlay. Interestingly, my 3452 has well over 10,000 (crazy OCD) fairly hard openings.....and closings. It was actually a little sticky, being straight titanium on steel, for the first few hundred flips. But I was thoroughly impressed when it smoothed out and stayed that way over 2,000, 3,000, 5,000 hard openings and beyond. The two identical models I bought for my kids were smooth as melted butter from day one.

None of my frame locks locked up to the point I couldn't release with with a thumbnail wedge.




•••••••••••••••

Sent from my mind....using Tap-a-Thought. (tm)
 
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Well, I went and got my other ZTs--0350 (de-assisted), 0801 (pimped), and 0450. None of them appeared to have a concavely-milled locking ramp on the tang. I took another look at my 0452 and am thinking now i was in error regarding the milling on its lock-ramp. It seems to have been an illusion created (before my old eyes) with the knife in the open position and the lock-bar making it appear that the engaged portion was "flatter" than the exposed. Looking at them all, they appear to be in the range that a previous poster had cited as Michael Walker's ideal of 7-8 degrees. Of the four ZTs I have the 0801 and 0452 can be forced over to make unlocking overly difficult, but I can't imagine normally gripping the knife in such a fashion with even when cutting hard.

I guess I'll be getting out my other frame locks to see wasp with them.
 
Reate, Kizer, Strider, Mircotech, Benchmade, Hinderer, Spyderco, framelocks I own that have solid unmovable lockup. Don't know why some ZT'S would , but I honestly don't see it a big problem because they won't go over so far as to unlock and flipping them they lock up solid and early.
 
I find this to be an issue with steel lockbar inserts. Especially when paired with a ramp lockface and /or slip fit construction. You can set up a knife to minimize the issue. The main culprit is keeping the pivot as tight as possible so that there is no give. Buy there are other things like loosening the screws and forcing the handle halves in seperate directions so that the lock bar has the earliest lock up possible. Then tightening them back down. I will admit i have had a few knives that have done this but necer to the point it was difficult to close. But i also have a different technique when holding a knife and I am not putting much force on the lockbar.
 
FlaMtnBkr said:
Jill, that 0804 looks to me to have an angled lock face. Are my eyes playing tricks or does it just not have as much as your other knives? I looked at my 0804 and it has an angled lock face and doesn't move over much at all with pressure in the locked direction.

I assume from the way the thread has progressed that the knives in question are likely Ti framelocks with a steel insert?

From what I've read about a book describing liner lock construction by Michael Walker who invented the liner lock, the blade lock face should have an angle of 7-8 degrees. Any less and the lock can wear quickly and travel all the way across like mentioned here, and more can cause lock rock and a lock bar that wants to push over and potentially unlock. Since a frame lock is essentially a liner lock without a decorative scale, which I can't see how Chris Reeve got a patent for, much less praise and acknowledgment for the frame lock 'creation', and most makers follow this same rule of a 7-8 degree lock face as stated by a few custom makers on forums and observed on actual frame lock knives. So if someone has a knife with a lock face that is cut straight across I would think there was a manufacturing defect or much worse, a bad design.

Anyways, all this is why I don't like frame and liner lock knives much. They need to be made just right and very small changes can greatly effect function, strength, and reliability. And you can have 2 knives of the same model and one knife can work fine and the other has problems or even fails. I have multiple fail and as a mechanical engineer I see the design as a bunch of compromises. For a light use knife that is used like a slipjoint it is probably fine. But trying to make a heavy duty knife to beat on and do things a knife shouldn't be used for, I personally don't see it as a very good design especially if you have to beef it up and oversize parts. But they have become popular for some reason. I feel like the lock was originally used when the patent expired because it was one of the few options for a lock and picked up steam from there. I would think licensing a different lock would be a better option but consumers line up to buy them so nothing will change while that still happens. I really don't see the desire to use them with a flipper since the detent has to be tuned and made just right and it's even a well known fact. Where other locks are much easier to adjust with different springs or longer contact with spring pressure. My best flipper is a Kershaw RAM that uses the HAWK lock. It opens effortlessly and reliably and similar locks that are held closed with spring pressure should also make great flippers with no need for 'tuning'.

I'll get off my soapbox and end my rant.
Click to expand...


"Mike (Walker) emphasizes that there is no single correct angle for

this bevel, as some writers have mistakenly claimed. Rather it

must be determined for each knife. The optimal angle is a

function of the blade and liner materials, of the spring tension

of the liner, and most important of all of the overall length of

the knife. The free end of the liner moves in an arc of a circle,

and the length of the knife determines the radius of this circle. "

from Bernard Levine's article still online about this....

http://www.knife-expert.com/liners.txt

a great read of a piece of history and how strong a properly made liner lock actually is....



in that regard the liner or frame not being made correctly is one of the major reasons so many feel they are weak and dangerous.
 
My Umnumzaan goes pretty far over when doing heavy cutting.
My ZT 0804CF goes over a bit, but not all the way.
My Buck CSAR-T (liner lock) goes most of the way over in heavy cutting.

My opinion is a resounding "So what?"
I just unlock the knife and put it back in my pocket.
The lock worked fine as it kept the blade locked open...that's what locks are for. :)
 
I used to read hard use tests and I remember them saying the liner lock, only got tighter during spine-whacking just as it should. This was before framelocks became so popular.
 
jbmonkey said:
"Mike (Walker) emphasizes that there is no single correct angle for

this bevel, as some writers have mistakenly claimed. Rather it

must be determined for each knife. The optimal angle is a

function of the blade and liner materials, of the spring tension

of the liner, and most important of all of the overall length of

the knife. The free end of the liner moves in an arc of a circle,

and the length of the knife determines the radius of this circle. "

from Bernard Levine's article still online about this....

http://www.knife-expert.com/liners.txt

a great read of a piece of history and how strong a properly made liner lock actually is....



in that regard the liner or frame not being made correctly is one of the major reasons so many feel they are weak and dangerous.
Click to expand...

The part im struggling with is the claim that the overall length effects the radius of the arc circle. You can increase or decrease the overall length of a knife and the liner and lockface never need to change. I cant see how that arc would change unless every aspect of the knife increased at the same time. But you could theoretically have a long knife with a shorter radius than a shorter knife depending on how long you make the lockbar on each knife. Maybe its under the assumption that all things are equal and that were talking identicl knives in different sizes.
 
stabman said:
My Umnumzaan goes pretty far over when doing heavy cutting.
My ZT 0804CF goes over a bit, but not all the way.
My Buck CSAR-T (liner lock) goes most of the way over in heavy cutting.

My opinion is a resounding "So what?"
I just unlock the knife and put it back in my pocket.
The lock worked fine as it kept the blade locked open...that's what locks are for. :)
Click to expand...

I'll have to agree with this. As much as it annoyed me, it did exactly what it was supposed to do. Keep the knife locked open. My Sebenza 25 can be pushed over too... but it unlocks completely normally so I don't ever notice it.
 
PURPLEDC said:
The part im struggling with is the claim that the overall length effects the radius of the arc circle. You can increase or decrease the overall length of a knife and the liner and lockface never need to change. I cant see how that arc would change unless every aspect of the knife increased at the same time. But you could theoretically have a long knife with a shorter radius than a shorter knife depending on how long you make the lockbar on each knife. Maybe its under the assumption that all things are equal and that were talking identicl knives in different sizes.
Click to expand...

Spyderco Tuff is a good example. But I think the quote from the article is supposing that "generally a longer knife will have a longer liner lock" and in that sense it's true. But you are right, the locking liner can be cut to what ever length one chooses independent of handle length.
 
PURPLEDC said:
The part im struggling with is the claim that the overall length effects the radius of the arc circle. You can increase or decrease the overall length of a knife and the liner and lockface never need to change. I cant see how that arc would change unless every aspect of the knife increased at the same time. But you could theoretically have a long knife with a shorter radius than a shorter knife depending on how long you make the lockbar on each knife. Maybe its under the assumption that all things are equal and that were talking identicl knives in different sizes.
Click to expand...

dont know. its written second hand from mr. Levine, speaking with Michael. i cant speculate as it would based on my 3rd hand interpretation of a second hand writing. you could likely do a better job being in the same position i am on the article reading. i imagine it might have been kept short for the magazine article. editors and all involved in. just speculating though. ill let the mechanical engineers and other experts answer this.
 
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