Buck marksman lock test

Bigfattyt said:
I have had a jolt close a knife in my hand in use. Cutting hoses in very tight space. On a cubic hydraulic press. Push cutting and sawing a hose at an awkward angle and the knife spine contacted the steel side of fhe press. Cut my fingers. Not badly.

Different liner lock I was topping boxes at a job. Poked the knife into cardboard, and it closed on my thumb. Slight download pressure on the spine caused the liner lock to disengage.





Spine walk tests cause many style knives to close.

It is damaging to liner locks and frame locks.

I do check my liner locks and frame locks and back locks to check that the lockup is tight.

I have Triad locks that won't fail a spine walk test....but I don't need to bang my edge on anything to double check that.

So I've been cut when a liner lock failed with light negative pressurez and also a separate liner lock with a slight jolt to the spine.

My older brother was cutting thick sidewall rubber ( trying to pierce to initiate the cut).. he had to have surgery to reattach his tendon.

I've seen more than a few other cuts from liner locks and frame locks.

I have retired liner locks for the locks repeatedly disengaging with light spine pressure.
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on liner and frame locks. if the geometry is incorrect you don't have to spine whack to test it. a simple keep fingers out of the way and press on the spine and watch how the liner or frame lock moves. proper geometry will stay still and move towards more lock up. improper will move towards unlock. doesn't require a lot of force to see and won't harm the locks either. I test all mine before carrying them.
 
jbmonkey said:
thank you. what i was wondering about is happening. youre holding on to the lock bar as you spine whack it. its going to open even on a lighter tap. try holding below this lock bar so your hand isn't pulling it open as you hit the board. dont know if it will open or not and it likely will open, but will be a much better test. thanks.

if ya can't figure it out how not to pull open the lock when doing your retest, I'll post pics of how to hold safely and get a real test on it tonight for ya.
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Here is a few more i tried, its pretty obvious that supporting the lock with your hand is where most of the strength is coming from. In the last video i tied a tight nail knot compressing the lock and really hit it hard and it never failed. Still no play at all, also no deformation of the tang or lock bar.
 
ohen cepel said:
Aside from the question of method and if spine whacking matters at all (I think not), I also think your lock could be adjusted a bit better.
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what should i look for when adjusting it? I believe buck says the lock is optimum when there is a slight gap between the lock bar and scales, if there is no gap then it should be adjusted to eliminate blade play.
 
Mr.Conservative said:



Here is a few more i tried, its pretty obvious that supporting the lock with your hand is where most of the strength is coming from. In the last video i tied a tight nail knot compressing the lock and really hit it hard and it never failed. Still no play at all, also no deformation of the tang or lock bar.
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:thumbsup: good follow up tests. well done. thanks for taking the time and showing us.

another question......is your lock bar tightened and adjusted properly.....just asking as I assume it is but if I don't ask I dont know. not sure that will have any effect on results of testing but never hurts to see if it does. course you're doing all the work, so easy for me to run my trap.:D

lastly its g&g hawks design not Bucks. true Buck made it, but they didn't design it. we may see this lock design made by someone else down the road unless Buck bought the rights to it....that kinda info is way over my pay grade .

thank you.
 
jbmonkey said:
:thumbsup: good follow up tests. well done. thanks for taking the time and showing us.

another question......is your lock bar tightened and adjusted properly.....just asking as I assume it is but if I don't ask I dont know. not sure that will have any effect on results of testing but never hurts to see if it does. course you're doing all the work, so easy for me to run my trap.:D

lastly its g&g hawks design not Bucks. true Buck made it, but they didn't design it. we may see this lock design made by someone else down the road unless Buck bought the rights to it....that kinda info is way over my pay grade .

thank you.
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i assume its adjusted correctly, buck says there should be a slight gap between the lock bar and scales and there is no blade play, like i said before i love the knife and will still carry it.
 
Mr.Conservative said:
i assume its adjusted correctly, buck says there should be a slight gap between the lock bar and scales and there is no blade play, like i said before i love the knife and will still carry it.
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gotcha. thanks for checking......just more accurate results is all.

yeah I get that. I like mine too. I don't think anyone thinks ya dont....for me it was more understanding the results and what went into them. I enjoyed your tests....whether reveleant for using or not, now we know what it can and can't do.

as an example.....same with Maks test grinding it under his 4x4 tire. knife worked fine pocket clip got sheered off. Mak was trying to destroy his to prove its a tough knife, and it is. im never going to do that stuff but I know it could handle Maks testing and yours if I hold the lock bar.
 
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I do hear people say all the time "I never put pressure on the spine of my knife because I cut wirh the edge"..... if you have ever stabbed anything you likely out pressure on the spine of the knife.

If you ever use a non trailing point knife to pierce anything, you will likely exert pressure on the spine.


If an item you are piercing or cutting is not stable or moving, your knife may experience pressure on the spine.


Food for thought.


I'm not a knife fighter. But I have stabbed and cut a lot of things..... in my life.... meat, cardboard... wood, pumpkins...leather.
I've carried and used locking and non locking knives my whole life.

Even in wood whittling....you will occasionally experience a non locking knife stick in the cut and fold, when attempting to pull the blade back from a cut. I've had this happen too many times to count with slip joints and friction folders while whittling.
 
jbmonkey said:
on liner and frame locks. if the geometry is incorrect you don't have to spine whack to test it. a simple keep fingers out of the way and press on the spine and watch how the liner or frame lock moves. proper geometry will stay still and move towards more lock up. improper will move towards unlock. doesn't require a lot of force to see and won't harm the locks either. I test all mine before carrying them.
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I do this test on locking folders. Im not a spine wack test fan, as I've seen it render locking knives into non locking knives. You can ruin the lock interface easily, especially on liner and frame locks.
 
I've used slip joints for years and still have all my fingers.
I kinda group lock strength and battoning threads in the same category.
..... They both involve unreasonable product use and expectations
 
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Law of physics proved, inertia, an object in motion tends to stay in motion. When it comes to a sudden stop from the impact on the board the lock tends to keep moving and releases the blade. That's logical.
 
st8yd said:
Law of physics proved, inertia, an object in motion tends to stay in motion. When it comes to a sudden stop from the impact on the board the lock tends to keep moving and releases the blade. That's logical.
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Yes that’s exactly what happened in an unorthodox way. It didn’t fail because it did what it was supposed to do using inertia . The lock bar released the blade to close. Now if the knife were held still so that the lock bar were not in motion and the same force applied it might make a big difference but still not a relevant test for typical usage. The follow up video shows with the lock bar secured from the inertia it held.
 
ohen cepel said:
Aside from the question of method and if spine whacking matters at all (I think not), I also think your lock could be adjusted a bit better.
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Yes! Tighten the lock first with the Allen wrench, I believe this issue will go away
 
The lock bar did what it was supposed to do. It went out from the lock catch on the blade because of inertia just as if you were lifting it to release and close the blade. So tightening the screws won’t accomplish anything. It was simply the inertia from whacking it backwards from its intended method of use. Just don’t whack the spine and it will do it’s job!
 
I really hate to burst your bubble,but you can spine whack any folding hunter right out of Thr box and it will fail like the marksman.lol.
 
Mr.Conservative said:
But today i was talking lock up with my brother on his ZT 0640 and how i thought the frame lock would slip so we decided to spine whack some blades on a 2x4 clamped in a vice.
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I am going to be blunt. If you test a knife using spine whack, you are detached from reality. Reliability tests need to be for the real world. I can guarantee that if challenged to a race, my Jeep will beat a Maserati if I get to choose the route. Here is something I told my students when I was teaching furniture design, "For most woodworking projects such as furniture, virtually all species have sufficient strength. For example, black locust has a compressive proportional limit strength of 6800 pounds per square inch. In terms of compression failure, how big do the four legs of a chair have to be in order to support a 250 pound person. A quick calculation shows that each leg needs a cross-sectional area of slightly less than 0.01 square inch. However, no chair has such sliver-like legs. First, joinery would be impossible. Second, compression failure is not the only factor to
consider. For a column (the legs), buckling will occur if the ratio of length to least dimension is greater than 11. Compression, tension and shear strengths of wood may be great enough that they may be ignored for most situations; however, bending must be considered." Test a knife for its intended purpose, not some fantasy.
 
RAZORBLADES said:
I really hate to burst your bubble,but you can spine whack any folding hunter right out of Thr box and it will fail like the marksman.lol.
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That’s simply not true. Most lockbacks from reputable makers, and all triad locks, will not fail that type of spinewhack out of the box.

As Bigfattyt Bigfattyt said, stabbing/piercing often applies negative load on the blade. He mentioned himself and his brother have been cut due to failing locks. I myself have had a minor injury from an accidental spine whack while working in a very confined area.

This particular lock I know nothing about. Sounds like it could be a matter of adjusting it.
 
bertl said:
I am going to be blunt. If you test a knife using spine whack, you are detached from reality. Reliability tests need to be for the real world. I can guarantee that if challenged to a race, my Jeep will beat a Maserati if I get to choose the route. Here is something I told my students when I was teaching furniture design, "For most woodworking projects such as furniture, virtually all species have sufficient strength. For example, black locust has a compressive proportional limit strength of 6800 pounds per square inch. In terms of compression failure, how big do the four legs of a chair have to be in order to support a 250 pound person. A quick calculation shows that each leg needs a cross-sectional area of slightly less than 0.01 square inch. However, no chair has such sliver-like legs. First, joinery would be impossible. Second, compression failure is not the only factor to
consider. For a column (the legs), buckling will occur if the ratio of length to least dimension is greater than 11. Compression, tension and shear strengths of wood may be great enough that they may be ignored for most situations; however, bending must be considered." Test a knife for its intended purpose, not some fantasy.
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im going to be blunt, but if you are under the illusion that you never put negative pressure on the spine of a knife, than you are detached from reality. As someone has mentioned earlier if you do any kind of piercing than pressure is applied to the spine. Also the spine of a knife can have many uses like scraping and other things, to preserve the edge of your blade. A spine whack test is not saying “this is a real world scenario where i beat the spine of my knife” it is a experiment to show a locks strength with negative pressure, that could come up in many situations, the test is just the simplest way to apply force to the spine for observation.
 
RAZORBLADES said:
I really hate to burst your bubble,but you can spine whack any folding hunter right out of Thr box and it will fail like the marksman.lol.
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false, many folders hold up to spine whacks much harder than what i did. And if you read the whole post i said i also spine whacked the buck spitfire and it never closed. Hope that didn’t burst your bubble
 
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