A Little Bit of Confusion about Framelocks...

Joined
Oct 27, 2008
Messages
1,387
I was just comparing my SNG, Small Seb 21 and Galyean Pro Junkyard Dawg and noticed the thickness of the framelocks. Though the three of them have different Ti thicknesses, the cutout towards the bottom seems to be about the same thickness across the board.

Doesn't this basically mean that the locks are all the same strength despite the different thickness of Ti? If they were to bend, they would bend/give at the site of the cutout, no?

Excuse me if I'm confused or should shut up.
 
From what I know of how a frame lock works, you're pretty much right. The cutout is completely necessary to get the flex needed for for the lockup in the first place, but it becomes a structural weak point.

Doesn't necessarily mean it's GOING to bend/give/break there, but it is the most likely spot. I'm sure most manufacturers realize this slight design flaw going in and plan for it accordingly.

Oh, and FWIW, I don't think there's a dumb question out there when it comes to folding knives and how they work. I'd never hesitate to ask a question like that. How else are you gonna learn? And who knows? Maybe you, or someone who sees your question answered, will end up the next Ken Onion or Rick Hinderer.
 
The thickness indicates how much surface area on the edge of the frame lock contacts the back of the blade. The more surface contact, if made correctly to high standards, would mean a more solid lockup. I'm not an expert by any means. Just a hypothesis.
 
I was just comparing my SNG, Small Seb 21 and Galyean Pro Junkyard Dawg and noticed the thickness of the framelocks. Though the three of them have different Ti thicknesses, the cutout towards the bottom seems to be about the same thickness across the board.

Doesn't this basically mean that the locks are all the same strength despite the different thickness of Ti? If they were to bend, they would bend/give at the site of the cutout, no?

Excuse me if I'm confused or should shut up.

This is what makes a Reeve Integral Lock (framelock) no stronger than a liner lock. Sometimes a well made liner lock will even be a little stronger.

The advantage with the R.I.L. (framelock) is reliability. You hold the lock bar in place with your hand, it doesn't flex under pressure, and it doesn't move when the handle is twisted. It can also be beneficial to use Titanium since it naturally binds with steel (doesn't like to slip under pressure). Ti will wear out faster, but that is normally only an issue after decades of use.
 
A chain is only as strong as it weakest link, so yes the cutout matters. Some cut that area thinner than others and thats why I don't "hate on" liner locks. Most liners are bent over with no cutout, so in theory they could be just as strong as a framelock, if you go by the cutout. :cool:

Framelocks do lockup harder the more you grip them, but I wonder if your lock was going to "slip or break" would it anyways? How much better is lockup when your gripping during use?

Anyways not my picture, and I'm sure this was an abused HD-7 but.... this is what a framelock failure looks like if the lock does not slip :cool:

dsc04000l.jpg


This picture also shows why Strider and Rick Hinderer and a few others like their cutouts on the outside of the lockbar and NOT the inside. See how the force does not travel a straight line from the tang down the lockbar? On this HD-7 the force is transfered down the lockbar, then has to make it's way around the cutout... and that's where the failure was at. I wonder if the force traveled in a straight line like a SMF, SnG, or a XM-18 would it of failed that way?
 
Last edited:
My Small 21 was much thicker in the cut out than my PT or Pro Series, just like my Mnandi and other Smalls.
 
Just some more info on the HD-7

The person was batoning with the knife, if I can remeber VERY forceably, though the lock broke the knife did not close on him.

As to the original question: I dont know much about it so thanks for the question now I can learn as well.
 
Don't forget to factor in the depth of the lock-bar, i.e. the distance feom the top to the bottom of the lock-bar, the cutout along the bar length.

As long as the lock thickness of the grip frame slabs is sufficient to pervent the lock-bar from bending elsewhere of the cutout, as seen on most liner-locks that flex along their whole length, the cut-out should be the weak spot.

Never understood why the makers choose to make the cutout area so thin. I guess there are a lot of weak fingured people out there. Look at the newish Benchmade 755 - rediculous.
 
This is why I don't understand the suggestions & praise of framelocks in threads about 'beefy' folders. The lockback, axis, ball bearing, and compression locks have all been tested/rated higher, and I'm certain that the triad does about as well as any of those as well. Framelocks are as strong as liner locks, which is probably strong enough for almost any use, but they are not heavy duty locks in comparison to the rest.
 
From what I know of how a frame lock works, you're pretty much right. The cutout is completely necessary to get the flex needed for for the lockup in the first place, but it becomes a structural weak point.

The cutout(s) can have various forms. E.g. BM Gravitator (while linerlock by definition, the lock is an integral part of the liner/frame just as with framelocks) has several shallow ones providing enough flex.

IMG_4187.jpg


IMG_4197.jpg
 
A chain is only as strong as it weakest link, so yes the cutout matters. Some cut that area thinner than others and thats why I don't "hate on" liner locks. Most liners are bent over with no cutout, so in theory they could be just as strong as a framelock, if you go by the cutout. :cool:

Framelocks do lockup harder the more you grip them, but I wonder if your lock was going to "slip or break" would it anyways? How much better is lockup when your gripping during use?

Anyways not my picture, and I'm sure this was an abused HD-7 but.... this is what a framelock failure looks like if the lock does not slip :cool:

dsc04000l.jpg


This picture also shows why Strider and Rick Hinderer and a few others like their cutouts on the outside of the lockbar and NOT the inside. See how the force does not travel a straight line from the tang down the lockbar? On this HD-7 the force is transfered down the lockbar, then has to make it's way around the cutout... and that's where the failure was at. I wonder if the force traveled in a straight line like a SMF, SnG, or a XM-18 would it of failed that way?

Just some more info on the HD-7

The person was batoning with the knife, if I can remeber VERY forceably, though the lock broke the knife did not close on him.

As to the original question: I dont know much about it so thanks for the question now I can learn as well.

How did that happen by batoning? Did he have the edge pointing up and Batoning the inside of the knife? If it was normal batoning there would be zero pressure on the lock because the force of the blows would be against the stop pin. If anything should fail it should have been the pivot or the stop pin. It looks like he pryed from the inside of the lockbar to make it bend that way.
 
The cutout is completely necessary to get the flex needed for for the lockup in the first place, but it becomes a structural weak point.

Doesn't necessarily mean it's GOING to bend/give/break there, but it is the most likely spot. I'm sure most manufacturers realize this slight design flaw going in and plan for it accordingly.

I agree, but I must also point out that if it is the weakest spot in the structure (aside from the mating of the frame-lock face to the tang of the blade) then that is where the structure has to fail by definition. If the frame lock face does not slip off the tang of the blade (because the force of friction increases as the load increases), then it will always fail at it's thinnest cross section.
 
This is why I don't understand the suggestions & praise of framelocks in threads about 'beefy' folders. The lockback, axis, ball bearing, and compression locks have all been tested/rated higher, and I'm certain that the triad does about as well as any of those as well. Framelocks are as strong as liner locks, which is probably strong enough for almost any use, but they are not heavy duty locks in comparison to the rest.

I do agree. The framelock is both the lock and the spring and is therefore prone to the buckling effect. A thick blade and a large pivot don't make of a folder a hard use one when the lock isn't the strongest.

dantzk.
 
Last edited:
A chain is only as strong as it weakest link, so yes the cutout matters. Some cut that area thinner than others and thats why I don't "hate on" liner locks. Most liners are bent over with no cutout, so in theory they could be just as strong as a framelock, if you go by the cutout. :cool:

Framelocks do lockup harder the more you grip them, but I wonder if your lock was going to "slip or break" would it anyways? How much better is lockup when your gripping during use?

Anyways not my picture, and I'm sure this was an abused HD-7 but.... this is what a framelock failure looks like if the lock does not slip :cool:

dsc04000l.jpg


This picture also shows why Strider and Rick Hinderer and a few others like their cutouts on the outside of the lockbar and NOT the inside. See how the force does not travel a straight line from the tang down the lockbar? On this HD-7 the force is transfered down the lockbar, then has to make it's way around the cutout... and that's where the failure was at. I wonder if the force traveled in a straight line like a SMF, SnG, or a XM-18 would it of failed that way?

Perhaps the addition of a Hinderer lock bar stabilizer might have changed the failure mode a bit in this case too?
 
Calling, STR, calling STR, please comment about relief cuts and lock strength or just pull one of the gizillion threads that you have laid the smack down on, up and post in this thread.

That is all.
 
How did that happen by batoning? Did he have the edge pointing up and Batoning the inside of the knife? If it was normal batoning there would be zero pressure on the lock because the force of the blows would be against the stop pin. If anything should fail it should have been the pivot or the stop pin. It looks like he pryed from the inside of the lockbar to make it bend that way.

Hi mmarkh -

Looking at it, and speculating (which is a no-no I suppose...), it sure looks like a spine-whacking job to me - if it were batoning, it would be against the stop pin like you mention.

best regards -

mqqn
 
I was just comparing my SNG, Small Seb 21 and Galyean Pro Junkyard Dawg and noticed the thickness of the framelocks. Though the three of them have different Ti thicknesses, the cutout towards the bottom seems to be about the same thickness across the board.

Doesn't this basically mean that the locks are all the same strength despite the different thickness of Ti? If they were to bend, they would bend/give at the site of the cutout, no?

Excuse me if I'm confused or should shut up.


You aren't confused. Some lock cuts are precariously thin and others are thick, some not even consistent. I have spoken about this time and time again and actually received hate mail about it at times from various sources. Once people take their blinders off and start realizing that if you spent half the effort looking at the knives you love with the same eyes you use to pick apart the knives you hate you'd start to see more objectively for whats right in front of you instead of viewing with a blind faith bias so often seen in fans of certain brands. I understand brand loyalty and I'm not condemning it but when you present something best you can sticking with the facts best you know how and people attack or go on attack after that well, it gets uncomfortable. Lets face it the truth sucks sometimes. But, once blinders are in place people don't want to see what you tell them about if it threatens their belief even though its hard to get around what is right in front of them sometimes. We see it with liner lock back and forth (urinating) matches all the time. Such is life I guess.

Anymore I avoid these threads or try to because they've gotten me in such hot water in the past but thanks Mike. I guess. :D I had missed this one.

I'll try to keep this short as possible for me. :p.
My He Man folder has been done with both a very shallow unseen lock cut for some folks that wanted it slightly easier to manipulate and I've done them without a lock cut in the rear at all also. This model is capable for a frame lock and in my own private tests its held more weight than other so called hard use knives. My He Man is called a he man because its lock is harder to manipulate but its also harder to accidentally disengage and being a slab design in titanium .095 thickness well, its about as good as a frame lock gets. Contrary to popular belief frame locks cannot count great strength as one of their fortes` and neither can many thin liner locks particularly long thin lined liner locks.

I'll let you in on a little known secret. Has anyone ever wondered how Steve got into doing frame lock conversions in the first place? Take a guess. Go ahead guess. ;) You got it. I tested some of my own before I realized they were not quite as tough and strong as I thought. Being too stubborn to admit I ruined the dang things, (some of them were expensive believe me) I just rebuilt them. I see locks all the time and sometimes I wish I didn't know what I know because I like em other than the fact that I know if I bought it I'd want to rebuild the lock when it got here and do it my way. Why buy one though at that point. I'll just make my own. Anyway, I have pictures of some too about like that one shown. I never post em because well, it would be bad for some and I'm not into that really. Usually they bend like that and kink and the lock is bent downward well, correction I guess its technically upward but you know what I mean. I suspect the lock stabalizer on that model gave it the type back bend leaving the lock semi straight because if if had not been there it would look a bit different and maybe even tear like some I've tested.

Some very thin ones collapsed like that at 65 to 68 pounds of free weight. None made it to 100 pounds. Some liner locks actually hold more weight. A strong liner lock may hold 130 pounds, most not so much, more like 100 pounds if lucky. It just depends on so much including the length of the knife tested and the blade length. As you may have figured out that ain't much compared to many of the locks we all see these days. Still though there are advantages to frame locks in that the hand helps the lock to absorb some of that and in the hand the frame lock can and does do an aweful lot of hard use jobs. Its still my personal favorite because it need not hold a house on the end of the knife to be useful guys. Its obviously flawed if you lean into it too much I guess but most never get that far. Not in use anyway. In abuse maybe but normal use no.

There is a large variance from company to company and from knife to knife not only in the thickness but in location of the lock cuts at times. I have two S2 CRKT knives with different length locks and lock cuts in different places yet they are the same model. I've seen Emersons done different from year to year. (see pic links) And in my own model after great expense at personal experimentation tearing up knives I no sooner got done building I finally got a down pat design I can live with and like even though I don't make many now but it works okay and I think for a frame lock its about as strong as you are going to find. .095 slab, no lock cut and basically not something you are likely to sit around flicking open all day but something capable of doing the job when you need it and locking up pretty stout. Bending .095 ti with no lock relief is a bear but I do it and there ain't no way that lock will hyper extend out the wrong way. It takes a tool and leverage to bend it at that thickness so the human hand ain't budging it beyond the point that you can free up the blade! :D Lock cuts provide the best of both worlds. You can manipulate the lock at a cost of strength making that slab design more like a thin liner lock in action, and you can still get the added benefit of having the hand and fingers physically securing the lock or a bit of a better feeling for reliability.

Maybe one day if I get cranky and old, senile or whatever I'd post some of the pics I've received over the years of knives mangled but for now no thanks. Not going there. For what its worth in most tests even though the lock does fold up and sometimes kink and even tear its usually not the most catastrophic defeats one can see in a lock. What that means is the blade is usually still open, so if you are going to have a lock defeat thats the way to do it so no one gets cut or not bad anyway, but maybe just a bad pinch and a bruised ego followed shortly by some choice words rarely used by sailors. Sometimes its difficult to impossible to close the blade actually.

http://www.bladeforums.com/forums/attachment.php?attachmentid=63384&d=1164952855

Two Emerson HD 7s different years made. Same other than? Guess.:D
http://www.bladeforums.com/forums/attachment.php?attachmentid=101695&d=1214777197

Well, thats all I have on it. I'll just add this. Don't let it sway you from liner or frame lock just because this can occur. Its still a very good design for most all things we do with our knives. Do we have to take the cuts that far down? No we don't. I personally wish makers or manufacturers offered some kind of tough use option or "He Man" option of their own to allow one to get a knife a bit stiffer and thicker. Its too much to ask though. I've sold some that folks have returned for me to thin more so they were not so hard on thumbs. Its not for everyone. With lock cuts left thicker comes a host of other things. Flipper its not. The detent ball really works and holds the blade closed well, sometimes the spring tension is such that you can really feel and hear the ball on the blade and other times the lock is so stout that if you are the type that likes to flick your knife open and closed a lot its just going to cause pre-mature carpel tunnel and a really sore thumb or a really big callus if you keep it up. Makers and manufacturers have to please a lot of folks. Its better if the action is easy and smooth and thats what everyone wants. So they do what they feel is needed to make it strong enough to serve, yet weak enough to be easy to use. There is a price for that and you are looking at it in that picture. It doesn't happen often but it happens.


EDIT: Oh my bad. I thought that was a Strider but I see its an Emerson now. Should have seen the lock cut on the inside. Speaking of which that means nothing. Where you put the lock cut has no connection with how the lock behaves in my experience. I've seen them go all ways and the lock cut on the outside or inside seemed to matter very little if any at all as to how the energy traveled or what the lock did. Like the liner lock in testing there is no rhyme or reason to how it behaves or why at times.
STR
 
Last edited:
Hi mmarkh -

Looking at it, and speculating (which is a no-no I suppose...), it sure looks like a spine-whacking job to me - if it were batoning, it would be against the stop pin like you mention.

best regards -

mqqn

Spine whacking its not. It takes more than spine whacks to do that trust me. Spine whacking brings other things like indented contacts and premature lock wear, vertical or what is also referred to as up and down blade play and sometimes rounded or chipped edges of the lock face but it won't be enough even on the heaviest knife to cause a kink in the bend like that. I've only seen that from hanging free weights on the tail or back side of the knife with the blade locked open in a vise or on some with a gloved hand and the blade in the vise while I really lean into it to see just how much it takes before something gives.

Like any chain there is a weakest link and any chain is only as strong as its weakest link. In liner and frame locks that weak link is the lock. It doesn't matter how much you beef up the other parts of the system because they have no effect other than making that system more out of balance if the lock remains the same. You can stick a bull pivot 1/4" in there and you can put a bull stop pin and G10 scales and a super duty hardware set of screws in it but if the lock is still a gents liner lock or cut down frame lock its not advanced one bit more really. The truth is even a 3/16" pivot and 1/8" stop pin would still be stronger and outlast most locks in a free weight hang test of this lock type.

I attributed it the other day privately to a guy like this. Looking at it from the stand point of an automobile lets consider and say for arguments sake that a gentleman's liner lock is like a four door Ford LTD family sedan. Now you can do a lot with that car as it has a big foot print, a big trunk, a powerful motor, a wide track and comfort for the driver and while you may be able to toughen it up by sticking balloon tires on it, and a cattle guard bumper on the front and even by painting it camo in a hard coat shell its still a Ford 4 door family sedan underneath and it always will be. Thats the myth of bull pivots, bull stops, G10 scales, tactical looks and grips, and whimpy thin long locks that were never designed for what they are used for in a nut shell description. If its still a gents folder starting out on the frame, all that nice hardware hasn't really changed it. If the four door sedan has all that great stuff you may get a little further up the goat trail in it thanks to those bigger tires but it will never be the four wheeler you really wanted. Like I said, sometimes the truth sucks. Deal. I'm easy to reach for all the hate letters. :D

STR
 
Last edited:
Back
Top