strider/ buck strider

I doubt all are the same SpyderJon. Some will be like that pictured and others will be just as you'd expect them to be with nearly 100% of the lock engaging the blade from perspective number 1.

As for perspective number two looking down on the lock, to see how much of the lock actually moves out across the back of the blade they all seem to me to be a little tighter than I'd personally like to see behind the blade. Tighter than I'd make for myself also. Shearing of the lock face under severe stresses seems to be a high probability on a lot of these current custom and production frame locks being offered. Sebbie locks typically cover 75% which is surely better than the lock barely coming out at all like the A.G.Russell sting I recently did a low rider pocket clip on. That lock barely came out at all. Not even a 1/16" of it was behind the blade to secure it and it is a .150 thick piece of titanium on that knife.

I have not handled an AR/GB yet so I cannot comment on those knives by Strider. I have seen enough in the others to know why the Sebenza is the standard by which all other frame locks are judged though. Chris' knives are the best engineered frame locks being made in my opinion. At least when compared to the ones I've seen in my shop.

I'd love to get my hands on an R.J. Martin as I have a feeling these set a high standard as well.

STR
 
I'm a final year Mechanical Engineering student. My initial thoughts are this:

A framelock will not suddenly fail because it's contact area got sheared by the blade tang. Not possible, I don't see that as a strength concern at all.

While spreading the load of the blade over a larger area of the frame lockbar will (sort of, but the rotation and uneven pressures takes away from this) be less stress on the surface of the lock and blade, the actual lock strength (as opposed to material preservation) is decreased.

A Moment is the sum of rotational forces. Ten pounds of closing pressure 2 inches from the pivot is half of what it is 4 inches from the pivot. With a lever long enough you could lift the Earth with your pinkie, right?

Anyway, a full lock contact area has a "middle" of where it the forces are located. So does the SNG lock pictured. And they both have to deal with the same stress. But by being farther from the pivot, the SNG can handle an additional load.

A smaller contact area provides more friction given the same total pressure. It will bite in like a track clutch, which has 3, 4, or 6 fingers pushing against the flywheel as opposed to 360 degrees of surface area.

In terms of the side to side issue Mick mentioned, he is simply applying the same concept but in a different direction. While movement of the blade with perpendicular stress (prying) is not a concern towards the G10 side of the SNG, it is towards the lock side. This is because if the lockbar plays in no part in stopping this flex of sorts, there is much less frame cross-section (and less than half of it is under the pivot on a SNG) to fight this battle. By having the lockbar engage the blade as far to the Ti side as possible, it now helps keep the knife stiff during prying. Yes, this will ever so slightly decrease its max strength against a perfectly linear closing motion, but it's a very small percentage compared to the side to side rigidity gained.
 
I follow your thinking. I don't agree with the 'not possible' comment about the lock shearing. I've seen it. Just ask Cliff Stamp.

I would say based on this info that it is probably a good thing in some ways but a bad thing in others. Titanium is not as durable as a steel lock would be that was near the same hardness as the blade. The titanium lock will indent from small surface area contacts. I've seen that and repaired many locks from this over the years.

What it really sounds like to me, mechanical engineering aside, is that its a good story for those that have a knife like the one pictured. I think I'd still pass on that one and take one that had more lock contact behind the blade or at least less of a gap that showed higher tolerances in the making of it. Especially when the lock is titanium.

But good info and certainly makes sense with the leverage contact area size and pressure as well as the distance from the pivot. But keep in mind here we are not talking about inches. We are talking about milimeters or less. I fail to see how advantageous a lock will be with less contact area over say one that had at least 70% of it contacting the blade it is supposed to keep secure especially when we are talking about a total lock width of appx. 10mm. The real question is: is there really going to be any noticeable difference from 3mm to 7mm of lock contacting the blade or vice a versa in normal use? Probably not. But what about extreme shocks and heavy use? Probably so. It seemed to me more risk to focus all the forces in a small 3mm area rather than make it bigger but if what you say is true then why isn't this more wide spread and seen in other frame locks throughout the industry?

As for the lock staying more on the titanium side? My question there is rather than risk shearing why not simply put a thinner liner of titanium on the other side? After all you are paying a premium price so why not get your moneies worth? Not that I expect you to answer that but simply that it comes to mind. Allow more lock behind the blade and more (dual) titanium liners for the lateral support instead of G10 or Micarta on one side by itself with no metal of any kind to help it out.
STR
 
talonturbo said:
A framelock will not suddenly fail because it's contact area got sheared by the blade tang. Not possible ...
Click to expand...

I have done it with a Buck/Strider, the face of the liner will shear crack readily when the engagement is small. I returned the knife and had it inspected. It doesn't even take a lot of force to do it.

The biggest concern with liners/integrals isn't actual gross strength, usually anyway, it is resistance to torques and impacts, and having a very tiny engagement, in both axis as noted in the above is a real bad idea for impacts.

In regards to rotational stability, it is far more rigid in regards to opposing rotation about the lateral prying axe, but I have never seen that actually induce failure of a liner/integral.

In this mode either the blade goes, or there is handle failure. There can be issues with liners/integrals if severely skeletonized as they will fail due to compressive strength in the sides of the cutout.

Reeve has the best stability I have seen to date on a liner/integral (small Sebenza) and his lock mates solid from front to back. His machine tolerance are really tiny, the knives are precision fitted. I would be surprised if many had such variances as STR noted.

-Cliff
 
Cliff Stamp said:
I have done it with a Buck/Strider, the face of the liner will shear crack readily when the engagement is small. I returned the knife and had it inspected. It doesn't even take a lot of force to do it.
-Cliff
Click to expand...

I'm not talking about a liner, many are too thin. I'm just saying I'd love to see you put the blade of a sng THRU the Ti lockbar. Do you mean you've actually chopped a piece of liner off using the blade or just cracked it? BTW, I haven't inspected a ton of framelocks recently, but the liner locks I have in front of me (Boa, CF Millie) both engage at the very "front" of the available blade/liner contact surface. The Millie looks close to even, but with light you can see it isn't any more than one corner of the liner. So I don't know why the complaints against the SNG. I'd say most companies use this technique. And it's not cheating, these are parts taken from patterns in most cases that cannot have the location of the stop pin modified. Everyone's doing it on purpose. Where have you been?
 
The stop pin can be modified by simply moving to the next bigger diameter pin which effectively moves it so the blade comes into contact with it sooner rather than later. For example: I've had Emerson knives in my shop for pocket clips or sharpening or some other repair and of the same model and yet with different diameter blade stop pins in them. How could that be? Maybe a year to year change in the design but I think its probably got something to do with the fine tuning of the knife before it leaves the factory.

Seriously though I didn't start this to make it into a big arguement. Its just my observations and my opinions based on years of working on, making and playing with knives as well as buying thousands of dollars worth for myself. I can safely say that not everyone is building them this way.

Your info is quite good though and I do appreciate understanding some of what must be going on in the design of a frame lock being done this way. I just think if we were building bridges it would apply more than it does in the small micron envirnonment of knife making tolerances.

STR
 
I hope nobody gets ticked and stops giving the info on this. This is not an argument, this is an education (at least for me) I want to make sure that the knives I have will operate as they are supposed too.

I never compared my Seb to the SNG concerning the lock differences until STR brought out his info. - I appreciate the mental spur.

My Hard use has been limited to wood carving, and I work it hard. - but I want to make sure that over time this is not going to evolve into blade play, or that could be a safety concern for me. I checked my Strider SNG and there is a very small contact point - which leads me to believe that could lead to a small groove..
If I need to have this re-worked I wanna do it now.

Also - just because Others have done the lock the same way Strider has, that does not mean it's the best method - am I overly paranoid - I hope so this time.

From my testing Strider has superior steel, and edge retention over any S30V models including the Sebs I have and had, that's why I have them but.. the lock has me concerned.

I shot an email to Strider to get their take, and have not heard back yet,but then again I wasn't sure I was using the correct one off their web site, so if anyone has an email address they know will get me where I need to get - please shoot me an email, I'd sure appreciate it.
 
talonturbo said:
Do you mean you've actually chopped a piece of liner off using the blade or just cracked it?
Click to expand...

Cracked it off, with partial engagement, you don't get even compression of the tang against the liner and thus shear can be induced, if the liner bends under the load, the shear is even more likely because now it is essentially an angled impact/load. With some liners/integrals the engagement is just barely making contact and this is a very low point of failure. It also causes a ton of security problems. It can be solved in many cases as Joe has noted by using either impacts or hard inertial openings to induce enough wear to get the lock to travel.

-Cliff
 
Sounds fishy to me, no point to cut the lockbar and tang so wide if contact is meant to be kept so far from the pivot. And what's the difference supposed to be between a frame and liner lock for shearing by the tang, the overall thickness doesn't matter, the contact area does.
 
STR, I own the latest Gen. AR with the contoured and grooved scales and it does have the same type of engagement as you are talking about. This is the design they are following, not faulty craftsmanship :)
 
Thanks for the info. I have not had very many of the owners of the knife you have report on it. I'd like to get a general feel of several like I have the SNG and the PT before drawing a conclusion though. It appears the PT has a higher percentage of full lock engagement of the blade than the others but I've had reports of SNGs out there with 100% mating of the two surfaces also and as I said the Buck/Strider knives seem to also be primarily 100% matings so that kind of goes against the on purpose theory a bit.

STR
 
STR said:
Seriously though I didn't start this to make it into a big arguement.

I just think if we were building bridges it would apply more than it does in the small micron envirnonment of knife making tolerances.

STR
Click to expand...

Not trying to argue, I appreciate the need to think logically. In all honesty, the stop pin mating surface of the Sebbie being curved is a smart feature. I'm not sure the radius of the curve on the Sebbie, but on the SNG it could use a smaller radius to more closely match the stop pin.

In terms of bridges VS knives, I don't see how size matters, basic laws still apply regarding forces, just with smaller values.
 
You may be right about the size issue. I'm just thinking out loud there..

I do think it was very enlightening in that first post you made though and it certainly helped me to get into the possible mindset behind designing a knife this way if it was in fact designed this way. I just wish I could believe it was on purpose by design and not a simple oversight on the part of the maker (S). In my own mind the jury is still out on that conclusion for the time being.

I have trouble believing its by design when the PTs I've seen and heard about from owners are all mating to the blades the way most locks on Kershaws, Bucks, Gerbers, Sebenzas, CRKT knives as well as others I've seen, owned and worked on are mating up to their blades.

I've always been taught that this was the 'ideal' to shoot for when making a liner or frame locking folder; that being to make as much of the lock face surface mate up to the blade as possible without allowing blade rock. When I saw one otherwise built it put a big ? mark in my mind. Then when I looked at the price of the one built in this way it really made that ? even more profound. I guess what really stands out to me is the degree difference in the gap on these high dollar knives.

Since discovering this one and several others I have noticed that more meet up with a lot of the lock engaging the blade than the other way around though. I've literally taken apart every liner and frame lock folder that comes apart in my collection just to get a feel for the majority of what is being sold and has been sold in this arena. I've checked to the best of my eye sight limits on some in displays all around my local area as well. It seems the Strider in pic #1 is in the minority based on my pseudo scientific inquiry in this matter.

STR
 
I think it should be noted here that the Buck/Strider products are purely Buck manufacture with Strider's blessing. It's not surprising that the two companies would have different ways of doing the same thing. Its a bit like the Buck/Mayo- similar, but when you put the production next to a custom you can still see the differences between how they build the knives. Same philosophy, different path to the end product.

Oh, and STR, you'd LOVE RJs knives. His Devestator is a marvel to use, and his knives are VERY well done.
 
BadKarma05 said:
can anyone tell me the difference in quality or features between the strider and the "Buck" Strider?
Click to expand...

I own a Buck 881 (small tanto) and a Strider PT. I use those knives as must be, in my opinion, use 3" folders: slicing, push cutting, no chopping,no prying.

The geometry of the buck blade (thickness, saber grind) gives a too thick edge. The flat grind and a thinner blade of the PT let me put a thin convex edge and the steel (S30V) is easier to sharpen,the edge holds much more than on the ATS34.
The liner of the Buck got quickly marks of wear and there is now such a play i don't trust in the lock. The framelock of the PT is still as it was in the box: no marks of wear, no "hard point" when i disengage the lockbar.
I will be short about other aspects: ergonomy, lightness, the PT is far ahead the 881.
I could say the Buck is one of the worst 3" folders i own and the PT one of best.

dantzk.
Click to expand...
 
STR said:
That is an interesting theory and even more so since the bottom part of the lock in the pictures I posted does not come into contact with the blade at all. The only part of the lock face touching the blade in the photos I posted is at the top of the lock not the bottom.

STR
Click to expand...

That theory isn´t new. I read about it in Bob Terzoulas book about how to make a tactical.....

Can´t tell on that particular knife, but the theory sounds like the knife really should look like that.

Bottom or top is a matter of direction.
 
Funny you should mention Terzuola. I get probably three of his knives a year into my shop with lock related problems. There is one (a left handed one) in my safe right now with a request from the owner for a low rider pocket clip and a side note to please tighten up the lock up. Every liner lock I've seen from Bob had what I would call severe blade play. Not developed blade play, they were made that way.

This one here in my safe right now has a blade that moves so much during use it is hard to believe someone paid $600 for it.

STR
 
Funny, that you have such experience. Have you ever talked about this with Terzoula?

Guess the book is relatively old year 2000, but still published.

I understood his recommendations that way, that it may be more prone to failure to get the whole flat in contact than one smaller point. I would imagine, if the flat is not perfectly fitted to the blade tang there must be a wobble. He showed this in a picture on page 97 pic. 136 "Correct contact between spring and blade" where a clearance is shown in the upper part (that is in the middle of the handle, not to twist up and down). The contact flat should be between .09" to .125" broad.

Bob Terzoula said:
If the spring contacts the top portion of the blade bevel, the blade will rock up and down. Ajust the play by removing material at the top part of the front of the spring to allow a little light to pass through there (Fig. 136)
Click to expand...

How do you manage this problems with his folders?
 
Its a simple smithing fix that many makers do including Emerson and others that I've spoken with at shows and via email.

You take the knife apart and lay the lock flat on an anvil so the detent ball is facing you and using a hardened flat end round 3/32 punch you peen into the lock about 1mm from the edge of the lock face to simply squish out a micron or more metal to make contact with the blade. Usually it is peened at the top and bottom but many times it is done in just one at the top well away from the detent ball and the center line of the pivot. It is a standard lock adjustment for when a lock has travelled clear across the blade tang. (liner and frame locks)Then you put the knife back together, and test it. If it sticks you polish the surface some until it moves right and send it home. I've done it many times on both my own hand made folders and forum members knives both new and well used.

You can see evidence of this same adjustment in many factory lock backs also. Just lift the lock bar up and look on the face of it where it meets the blade. If you see two or more little hash marks on each side of the lock bar guess what those are? They are fine tuning marks from the final adjustment of the lock up. Virtually every ZDP189 Calypso Jr. I have had in my shop has had these adjustment marks on the lock bar. They look like they were done with a flat head screwdriver.

I'm not trying lie to you or tell stories here. My reputation as a knife mechanic is well known around here. I do a lot of misc. work for forum members and before I did the internet thing I was well known at some of the local shows just ask around if you don't believe I have the experience I say I have. It isn't like I know anything more than anyone else I just tend to talk about stuff no one else seems to want to stir up. I guess someone has to write a book to be credible huh?

You can look in my custom pocket clip thread and see two recent Terzuola knives I've worked on but thats not all of them. Also, there is an email in bound to you Blop.

Thanks

STR
 
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