Framelock cutouts

K

kwackster

Joined
Dec 23, 2005
Messages
2,138
Hello Mr Rice,

I remember your words about the cutouts in certain framelock folders being to thin, and i was wondering what you thought of Benchmade's method of making those.

On the 750 Pinnacle folder the titanium slab isn't thinned out in the usual way, but instead a groove is carved out lengthwise on the inside of the titanium slab that forms the lock.

This seems to be a better way to protect the lockbar from buckling when the back of the blade is stressed, making the design stronger.
The weakest part isn't flat but U-shaped.

What do you think ?
:)
 
I've never seen a good photo shot of the area you speak of on that knife or had one of the 750s to look over closely so I really can't say my thoughts on it much from personal observation or use. I think there are a lot of theories about which is the best way to do the integral folder and the makers are all fairly diverse in the way they make theirs. Many seem to be fairly private or closed about it also. I can't say why but I suspect its just because they don't feel the need to explain themselves to anyone. I guess I'm just more open to discuss it than most or something. If I understand your description though it sounds like a good way to do it to avoid excessive vertical movement of the lockbar for sure.

We were just talking about this in another thread here and it basically covers a lot of my thoughts on this very subject and no other makers joined in even after I send them the links to the thread and asked them to feel free to contribute to anything we discussed. Anyway, for the record my thoughts again in a nut shell are that its become obvious to me that the relief to bend or spring the lock can be left thicker than most of the production or custom knives I have handled and apparently with no ill side effects if the contact and all other aspects of the folder are done with the idea of keeping the system in balance.

In that thread I said a lot but regarding the frame lock cuts I said this:

One of my biggest pet peves with many makers is how incredibly thin they take these cuts to spring the locks. Don't take this wrong because the length of the lockbar as well as the width in back at the cuts has a lot so say about how much you can leave behind when you make these cuts, but I will say it seems some get a bit carried away and take more than is necessary out of the lock. I've measured some as thin as .032 thickness on .125 or thicker slab sides the lock was made out of and yet the lock would probably have worked and been fine at .055 to .060 or thicker had they stopped there and tried it out. On other makes you can find knives with similar length and thickness lockbars with lock cuts left thicker that work fine. All I've ever been able to figure for this thinness is that they want them to be easier to push to release the lock, or they are concerned with how the lock can affect blade centering or something. I really don't know what the reasoning behind making one this thin is.

However, in defense of the knives out there made thinner here I need to point out that it does usually take a great deal of stress on the lock to kink or cause the lock to fold at this relief cut out point if the lock is sufficiently wide. It also seems to add something to the durability if the lock is supported by the hand in a user grip which somehow seems to add some reinforcement or even shock absorbtion for the lock but its my opinion after years of working on folders of this type as well as making them that the thinner the maker takes the relief cut the more vertical play and movement you will see in the lockbar. In other words there is a reason Strider needed to incorporate the lock stabalizer from Mr. Hinderer besides for hyper extenstion prevention going out the other way. I guess it didn't occur to them at Strider that they could probably have saved the money of having to license that stabalizer to use it and probably could have done much the same thing by making the relief to bend the lock thicker instead of cutting them down to .039 to .044 thinness on a .125" lock. Then the pocket clip could be made in such a way as to aid in hyper extension prevention. Heck I do that all the time on my own. But I seriously doubt you could make either the Hinderer or the Strider lock kink or fold in at the cut out and due to that stabalizer.

What I'm saying is that I wonder how much need there would be for a lock stabalizer at all if the lock was left at .065 or even .075 thick back there at the relief cut out and the long cut of the lockbar was made just a bit shorter to make it so that it offers less leverage on the lock bar to push it down or cause any up and down movement at all? It would be an interesting experiment in my opinion. And yeah, leaving the lock cut out .075 or thicker might make it harder to close the lock but it seems to me a big tough high speed operator should be able to handle a man's lock unless he just has a need to flip open his knife all the time even when he doesn't need it. ;)

The longer the lock bar is the easier it will be to bend it downward in use and when you combine this with a thin cut out in the other end of the lock to spring it, well, you know what I'm saying. If not, this is why so many of the locks on those bigger longer frame locking knives can wear quicker because it not only abraids the lock as its sliding into the ramp area to come into contact with the blade each time you open the blade but the lock moves up and down a minute amount in your grip in use from this vertical movement and over time this double wear does leave its signiture on the lockbar. When you combine that with very little of the actual lock only touching the blade to support it at the bottom of the lock for a corner of the lock at best maybe being a 1mm by 1/2mm surface area max instead of making a concerted effort to maximize that surface area contact like Reeves and others I've examined well, what happens is the lock wears and indents all that much easier and faster usually leading to vertical blade play. Again this is all the more reason that on the longer handled longer blade frame locks it only made sense to me to make the relief cut thicker to spring the lock while at the same time leave the lock bar long cut shorter as an effort to compensate for this added leverage the longer body of the bigger folder provides, but this is not usually the case and in fact what I've seen in just the opposite usually.

Its probably worth noting also that these type of defeats where the lock folds are not only rare in use but in testing when they do occur they are not usually the most catastrophic type of defeats you can see so in that regard most times the blade still remains opened when this occurs because essentially the lock is doing its job but the knife is for all practical purposes shot after that in regards to the lock because it will exhibit a lot of blade play and maybe not even close at all after this happens or at least not without scratching up the blade.

It always struck me strange that some of the so called hardest use folders being made were the ones with the thinnest cuts here on the folders to spring the lock. Look at the lock relief of the CQC12 I posted a link to in my other thread about frame locks another member started here and the Strider SNG also is another one for examples and in most all of them the areas cut out to bend the lock are far thinner on these hard use knives than even many much smaller frame locks like the A.G. Russell SeaMaster, or the Chris Reeve small Sebenza. Both of which are sold as non tactical up scale gents and user knives by the way. Also with the new JunkYardDogII and the NRG you can find liner locks of beefier stock from Kershaw with thicker stock hardened stainless locks that are probably overall stronger locks than these hard use folders costing many times the price as one of these Kershaws would run you. Go figure.

STR
 
Oh real quick I want to make sure to note that in no way do I mean to sound like I'm downplaying the ingenious lock stabalizer that my friend Rick Hinderer invented. It is quite effective and certainly a good way to deal with vertical lock bar play. A lot of guys deal with that in their own ways. In other words it is a known issue to deal with at times by all of us and Rick is not the first to try to come up with a solution to help solve it. Most would agree his is the best one yet though and since it solves both problems in one step well, that makes it very ingenious indeed.

Some other ways to deal with this are to simply cut the long cut of your lock cut outs so thin that if the lock did move it can't move much and of course as already mentioned, you can play with the length and width of the lock to make adjustments also. This thin cut idea is nice if you have access to a laser which can also enable one to make some pretty drastic curves and styles to enhance strength where needed. For those like myself that use a milling machine to cut our lock cuts we have to either design something of our own or license from someone smarter like Rick. Long before Rick's idea was known to me I started toying with various ideas of my own on inserts of steel or thin left over slices from .40 thick pocket clips I made out of titanium inserted in the long cut to physically block the lock from moving downward in your grip but then when I moved to the McMaster & Carr .035 thin cut off wheels it just happened to cut the exact size slot needed to fit a 2-56 button head screw in.

So for me a simple easy fix which I've used on my own frame locks at times (see pictures) was to simply mark one or sometimes two holes and drill them out using a #48 drill and thread them for a 2-56 screw. Then it was a simple matter of inserting two button head 2-56 screws so that the heads of the screws do the same thing as Rick's stabalizer and physically block the lock from traveling downward while at the same time allowing it to move from side to side free and clear. It actually works quite well but of course its only good for those thicker than .125 frame locks. Anything less and the head overhangs making it so you have to cut flat sides on them on both sides. Thinner stock can also make it quite difficult to drill without perfing the sides of your lock when preparing to thread the holes if you line things up wrong.

However once done correctly they do work fine also. If you position the pocket clip so that it acts as a stabalizer for hyper extension of the lock out too far the wrong way you have essentially covered the same bases in two steps that Rick covers in one. I often wondered about patenting it but how do you patent two screws drilled into holes and threaded?

I just sometimes find in life, as the old saying goes, that there is more than one way to skin a cat and I wonder to myself how many other makers have experimented with various lengths of the long cut out of the lockbar, in conjunction with the thinness of the lock relief to deal with this vertical movement vs the need to stabalize it in other ways??

I note many of them just accept it and don't worry about it taking it as part of the design. It seems to still work and has little to do with things regarding reliability or overall stregth but is just a general annoyance to some. Truth be told liner locks have exhibited it for years but no one ever noticed it because of the handle scale.

Anyway, I wanted to point that out.

Thanks

STR
 
Semi off topic...
I just wanted to add that many knife maker have taken to using partial scales or overlapping clips to prevent excessive lockbar bending.
 
Right, and thanks for posting. I have also done this using the clip but that is just for hyper extension only or lateral pressure opposite of the way the lock is sprung to force the lock out so it no longer comes in as it should to support the blade.
Doing those things doesn't solve the issue of the other type movement that has been noted by both end line users and makers which is vertical movement.

For vertical movement up and down there are other considerations for solving that problem or at least making it somewhat harder to notice. In theory one could

1) License to use the lock stablizer that Rick Hindererer invented. This actually solves both problems of excessive lockbar movement as have been noted by many makers of frame locks.

2) Or as others have done you can make the cut of the long cut for the lockbar using a very thin kerf laser if you have access to that technology or the thinnest kerf separating wheel can be employeed on your mill so that if the lock does move up and down it will bottom out quite quickly and touch the other end of the cut stopping the movement before it can move too far to really be noticed.
Here is a link to a very wide cut for the lock on the Storm II. Actually I believe these are stamped out which is part of why they are wider than if milled. http://www.bladeforums.com/forums/attachment.php?attachmentid=72739&d=1180033820

I've posted one by Rick Hinderer as a thumbnail to show one done very thin most likely using a laser.

My own come out as thin as I can mill them using a McMaster & Carr .035 thin kerf cut off wheel which is not the thinnest I can find but sure the most durable at that thinness.

3) Or also as I suggested earlier, the final thickness of the relief area to make the spring in the lock can be adjusted so it is thicker which can also determine how easy or how hard a lock is to hyper extend back the opposite way.

4) Or the overall length of the lockbar itself can be done shorter vs longer to reduce the ease with which it can be forced to move up or down.

5) Or the width of the lock at the lock relief cut area (not thickness) all can affect how easy or how hard it is to cause the lockbar to move up and down.

6) Incorporate some screws in under your long cut.

And of course one can play with all the above to find what works best for them.

STR
 
I have owned a few Storm II and have never noticed any vertical play, even under hard use. With the wide cut wouldn't you expect it?
 
I have several of the Storm II knives including that very special one of kind one shown in the picture that is a 64.5 Rockwell hardness model in a thinner profile overall than the factory production models sold that I was sent for testing and not one of them has noticed vertical play in use but if you partially open the blade and push down on the lockbar you can then see that it does indeed give a little but not very much and you have to look hard to see what it does give. Note though that the long cut is made short on that model as I've been saying can be done to greatly improve both resistance to hyper extension and vertical movement of the lock. You can see this obviously when compared to other folders of that size and also the lock on that Storm I and II model is hardened stainless steel not titanium. Those locks are 45 Rockwell based on the test I had them put through for my evaluations of them.

Its also worth noting that overall Kershaw does such a good job mating up their blades and locks and provide the users with as much surface to surface area contact as is possible without allowing a rocking blade that in my opinion they are probably the best production liner and frame locks being offered today as far as the overall angle of the contact, strength, and reliability of the locks and also the life expectancy from wear. I guess when you make as high a % of liner and frame locks as Kershaw you get pretty darn good at it. I'd say they are there for the most part.

You can wear them don't get me wrong. I've done it and taken a brand new JYD frame lock from barely engaging the blade to traveling all the way across the back of the blade so that the detent ball was trying to touch the opposite side liner but I had to spine whack the living crap out of it hard nearly 75 times trying to make the lock defeat before that happend and I hit it hard enough to drive tacks in a board easily in those wear and durability tests I ran it through for Kershaw.

Its also worth noting that the lock still held that blade firm and the knife never developed blade play at all vertically and it never defeated once. I tried to beat that thing to death hammering the blade with a smaller log and baton through wood logs splitting them and tweaking the lock sideways and the body sideways really giving it the what for. It held up to most everything I did to it including throwing it to stick in a dead oak tree out back and never broke or defeated but I did chip the blade. I later cleaned it up, sharpened it and gave it to a friend that liked it. Got to see it the other day for the first time in a while and its still working with no vertical blade play and you can't even tell I took a bit of the tip off the blade throwing it after my repointing of it. :thumbup:

STR
 
That makes sense from a perspective of torque, long lock-thin kerf, short lock-wide kerf.

Seems you really like Kershaws :) I love my Storm II's ,tried to love the JYD2 but could not get around that thick spearpoint blade. I really couldn't find a use for that blade shape on a daily basis.

With the technology and QC Kershaw have on their U.S. made blades I keep hoping that they will come out with a thin SS framelock with a nice thin utility blade (2-3mm MAX), think Opinel or pukko shape but in SG2 or D2. Big bull pivot or bushing included. That would be an everyman's Sebenza at an affordable price.
 
I have mentioned the word 'thin' a few times to them also and contrary to some that say otherwise they have made some changes there. My last two knives from Kershaw have both been thinner than older ones and they seem more than willing to work with their customers within reason.

I like the way you think though. Write Thomas Welk and suggest your thoughts. In some ways I think they have already done some of that though with the Zero Tolerance folders although they are a bit pricey for the avearage working man I guess. You never know what they might come out with next. Kershaw is hard on the move to not just keep up. It seems they want to be a leader and to be honest I've been very happy overall with a lot of stuff I've had from them over the last several years even before I knew Thomas or any of the other guys there but I'm still not a big fan of the assisted opening although I sure respect Ken Onion's ingenuity and the fact that it put Kershaw on the map for good in this industry.

The lastest knife I have from them, the NRG is also quite nice and seeing a lot of pocket time since putting some blue jean micarta scales on it.

You might like it better than the JYDII and it does have an equally thick set of liners in it.


By the way. I tend to just like good knives. Doesn't really matter who made it really. I tend to judge the knives on their own. There are several folks out there I don't much care for personally but I'll be the first to praise their knives. Strider, Lynn Thompson, and others just to name two.

STR
 
Glad to hear that more people are thinking "thin" is not a bad word. I have 20+ years of trekking and backpacking experience and never once had to chop down trees with my knife for fuel or shelter, even in some hairy situations.

I will think about contacting Kershaw but feel that I really don't have any "cred" when it comes to making suggestions. Just another BF nut thinking they know better. ;)

I agree with you on the AO. It is ingenious and a gold mine to Kershaw. I can't blame them for really pushing it. I do find that a quality knife with thumb studs is blazing fast. I think a lot of users are accustomed to discs or holes and use more of an arcing motion with their thumb, ergo they find it slow to open, tears their thumb, requires a lot of force or their thumb contacts the cutting edge. I found this is inefficient with studs and that they require a more linear motion applied parallel to the spine.

Will have to give the 1745 a try.

As always thanks for the opinions and great info.
 
STR said:
2) Or as others have done you can make the cut of the long cut for the lockbar using a very thin kerf laser if you have access to that technology or the thinnest kerf separating wheel can be employeed on your mill so that if the lock does move up and down it will bottom out quite quickly and touch the other end of the cut stopping the movement before it can move too far to really be noticed.
Here is a link to a very wide cut for the lock on the Storm II. Actually I believe these are stamped out which is part of why they are wider than if milled. http://www.bladeforums.com/forums/attachment.php?attachmentid=72739&d=1180033820
STR
Click to expand...

What if you would make that cut for the long cut for the lockbar in an angled manner ?
Now, each and every cut in every framelock that i know of is made at a 90 degree angle which gives the lockbar the opportunity to bend in, but, under spinal pressure, also outwards.
If you cut that long cut under, let's say 45 degrees pointing to the back of the folder, that lockbar can only bend inward, not outward.
And if you make that cut as you suggest with a very thin laser to create a very narrow cut maybe you wouldn't need a Hinderer or any other kind of stabilizer.

What do you think ?
 
I think any theory could be put to test but I'm not sure I follow exactly.

I've often thought of a cam lock built into the lock that could be a simple pin of hard steel. Lets say its a 3/32 diameter cylinder or even a flat bar set upright not flat so you could slide it along side the lock. To control the cam you'd need a L shape to it so you had a button or something or you have a thumb grooved slide either on the outside or the very bottom of the lock up where your hand wraps around it. When the lock engages you slide the cam forward and lock the lock so to speak by shoving the 3/32 cam or the flat bar into a hole drilled into the contact of the blade thus keeping the lock from moving up or down, or sliding off the contact. Whether or not you used the cam would be totally up to the individual.

STR
 
STR said:
I think any theory could be put to test but I'm not sure I follow exactly.

I've often thought of a cam lock built into the lock that could be a simple pin of hard steel. Lets say its a 3/32 diameter cylinder or even a flat bar set upright not flat so you could slide it along side the lock. To control the cam you'd need a L shape to it so you had a button or something or you have a thumb grooved slide either on the outside or the very bottom of the lock up where your hand wraps around it. When the lock engages you slide the cam forward and lock the lock so to speak by shoving the 3/32 cam or the flat bar into a hole drilled into the contact of the blade thus keeping the lock from moving up or down, or sliding off the contact. Whether or not you used the cam would be totally up to the individual.

STR
Click to expand...

I think i understand what you mean and it could work, maybe even in conjunction with my idea but it also involves more moving parts.
The idea of the angled lockbar cutout does not involve more parts, you just keep the titanium or steel handleslab under a 45 degree angle when you laser cut the slit.
Then the lockbar has nowhere else to go but inward.
 
STR said:
I think any theory could be put to test but I'm not sure I follow exactly.

I've often thought of a cam lock built into the lock that could be a simple pin of hard steel. Lets say its a 3/32 diameter cylinder or even a flat bar set upright not flat so you could slide it along side the lock. To control the cam you'd need a L shape to it so you had a button or something or you have a thumb grooved slide either on the outside or the very bottom of the lock up where your hand wraps around it. When the lock engages you slide the cam forward and lock the lock so to speak by shoving the 3/32 cam or the flat bar into a hole drilled into the contact of the blade thus keeping the lock from moving up or down, or sliding off the contact. Whether or not you used the cam would be totally up to the individual.

STR
Click to expand...

Why not a "lockback" lockbar? A lockbar with a lip, notch or contact area that would fit into a slot on the opposite frame, like a traditional lockback fit. Be the best of both worlds. Be a bear to fit and finish.
 
You covered that in your last thought. It'd be a bear.

STR
 
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