How strong is the average frame-lock?

CanonRebelXTi said:
Why does everybody worry how much a liner lock can hold on the spine? How many people do you know who cut with the spin of the knife? Or wack people with them? Even if it does fail, your pushing down. Back and forth sawing actions also dont generate much energy. Somebody care to explain why everybody performs a spine wack test or wants to balance a car on the spine of their knife blade?
Click to expand...

The simplest answer for the stength argument is leverage. Whenever you are trying to cut something for which you need a decent amount of force and you do it by pushing the tip in first, you are levering against the pivot. Imagine you are cutting through some thick, dense cardboard, which offers too large a resistance for your wriststrength to cut through it. So you push in the tip and you cut by a rocking motion, levering the tip against the material just like you do when you cut a can open with a can-opener (or a knife for that matter). If you leverage with your bodyweight, you can EASILY apply a force of a few hundred pounds at the pivot depending on the length of the lever (handle) which is why a rating in pounds per inch blade is so important. You also have to realize, unlike a slipjoint which will fail immediately, the locked folder will fail suddenly, far increasing the risk of injury in such a case.

The spine wack test has nothing to do with strength, like Allen said. If the lock does not engage sufficiently or tends to slip, it will be defeated not by strength but by being "jostled" around a bit. That is all that you are testing for. I had a lockback that simply wasn't engaging deeply enough (which you don't see, unless you dissassemble the folder). The lockbar was catching enough that it wouldn't close by putting weight on the spine, but one sharp tap with out much force will have the lockbar "bounce" a bit and it would slip out of engagement and fold the knife. Actually, quite frightening when you see a locked knife flip closed at a sharp tap on the spine.
 
ElectricZombie said:
I think a well made frame lock is probably the strongest lock around. I've never had a frame lock fail; even on cheap $20 knives.

I've had a few liner locks fail; one during use. For most cuttting tasks, lock failure wouldn't really matter because I'm cutting in a traditional manner. Even so, a lock should live up to it's name and remain engaged until I make a deliberate effort to close it.
Click to expand...

So wrong, even benchmade has said that their axis lock is at least 35% stronger then their framelock. And yes, their framelocks are considderd pretty tough. It is not a question of thinking but of presented critical data, in other words facts.
 
I feel the Axis is much more than 35 % stronger than a frame lock but I've tested out both. Frame locks are inherantly reliable. Strength is not their best feature. They are strong enough to suffice for most anything a man can put them through in the hand and thats all that really matters. In an apples to apples test of strength though many would probably be shocked to learn they're not that strong actually when compared to other lock types. In my own tests they won't hold the same weight as a good lockback, or a compression lock, axis lock, ball lock, ultra lock, arc lock or even many button locks which surprisingly can be quite strong if the pin diameter is sufficient.

STR
 
STR, did you use any particular methods to test the locks? I'd be interested to learn a little more about what work you've done with them.
 
darthsoaker said:
OK... so I have this problem with liner/framelocks.... I have a hard time trusting them. After buying a Kershaw Storm ($50 :cool: ) I found that yes, FL can be very reliable. (Duh.)

I still prefer other locks. No big deal, plenty of other fish in the sea. Kinda. FL and LL are verrrry popular on locking knives.

Several Kershaws have caught my eye. Of course, the are all framelocks, or souped up LLs.

I carry a knife/knives with a SD option in mind. Not PURELY for SD, mind you, actually, SD options is one of the lesser things I think about when I get a knife.

I'm wondering how strong NORMAL framelocks (NOT Strider style half inch sheets of steel ;) ) or strong LLs are. How much weight can they hold on the spine? 50 lbs per inch of blade 100 lb?

They type of knives I'm talking about are like the Kershaw JY Dog 1 & 2, Kershaw Lahar, and Kershaw NRG.
Click to expand...

I'm not an authority like many here buddy, just a guy that has owned some of the knives that you mention. I realised that Kershaw models vary considerably in the metal thickness of their liner locks. The Blur, that I really liked, had a shockingly thin L/L. Whereas the Storm and JYD2 are considerably beefier. An obervation: after half a years use my little Storm which never centered on lock, is still off center, which gives me pause for thought. My JYD2 which was fully centered (I requested that the seller check several before shipment to insure perfect alignment) and is still perfect. I use these knives to a moderate level considering their design limitations, but I don't baby them. I listen to those that know around here and have come to the conclusion that for a serious self defense application, however unlikely and secondary, I carry a fixed blade (KA-Bar large TDI). A misnomer as the large TDI is not that large really. Look at a TDI, moderate size, built like a tank, will not fold onto fingers, tucks into side of hip like glue, non existant profile under clothing, sheath has very little "hang" to be seen by others, quite inexpensive.
 
For strength testing its not rocket science the way I do it really. My theory is that in use any grown man or even many youngsters can exert plenty of weight on a knife, particularly in heated moments of emergency or adrenaline rushes due to circumstances. My idea was to find out which locks typically could stand up to all my weight if I leaned into one heavy and which could not. All I do is use free weights, stacked progressively on a bar bell on a cable tied through the lanyard hole. If there is no lanyard hole I'll many times drill one myself and use that for testing.

All you need is a good work table with a wooden vice and a block of hard wood the same thickness as the blade you are clamping, a cable of rubber coated steel woven twine, and a couple hundred pounds of free weights. I use this block of wood for support under the edge and clamped down in the vice and let the block sit on the shafts the vice moves on with the blade on top of it so as to not ding up the edge.

STR
 
If I can find a vice in our garage I might have to compare a few of my knives. When you do this to the point of failure are the locks generally trashed afterwards or do some remain usable? I'd imagine it would vary with the lock type of course.
 
Be prepared for liner and some frame locks to be ruined if you get carried away. (that is actually how I first was forced to make my first Emerson conversion when the lock folded suddenly and unexpectedly) Most of the others can surprise you at how strong they are. Axis, and all the clones similar, good lockbacks (Fulcrum II, Spyderco Manix, Mini Manix, Cold Steel Ultimate Hunter, Voyagers, Vaqueros) can be surprisingly strong and durable, and button locks can also surprise. Many of these you can test and other than cable marks and indenting in to the scales and maybe some grit marks on the blades from the stress they are fine with no tell tale signs otherwise indicating they were tested. In my experience after 220 pounds you are lucky if the wooden vice can even hold the blade any longer.

The Fulcrum II (with the lock for the lock engaged) and most full steel lined Axis locks will take about anything you pile on there and laugh it off. Even the little HK 14210 absoulutely amazed me at how strong it was.

STR
 
simplicity -thats why i like framelocks- no little parts or springs to break when you dont need that to happen-
 
Maybe I missed it in the above posts, but I have always thought that the reason that a framelock was more solid was that the tighter that you hold the knife, the tighter it locks.

In my wild ass imagination, I could see other locks accidentally being released by the user-even the axis and its' incarnations.

Personally, I like a good solid lock; however, I also use slipjoints. You just have to be more careful with them.
 
if you are worried about lock strength i would just get a fixed blade. Takes the problem right out of the equation.
 
Daniel said:
Maybe I missed it in the above posts, but I have always thought that the reason that a framelock was more solid was that the tighter that you hold the knife, the tighter it locks.

In my wild ass imagination, I could see other locks accidentally being released by the user-even the axis and its' incarnations.

Personally, I like a good solid lock; however, I also use slipjoints. You just have to be more careful with them.
Click to expand...

Thats why I said the frame locks have a super reliability in the hand. I think that the hand actually helps the lock bar to absorb shock better also as somewhat of a reinforcement but its hard to test it out. Still the locks would do a lot better with free weight if you zip tied it so it could not slide off the contact in the free weight test. But even then eventually you would kink the lock at the relief and although the blade would still be open its still a lock defeat even if it isn't the most catastrophic type of defeat you can see.

STR
 
In my experience, I have to say that the Extrema Ratio lockbacks are the strongest folding knives ever, bar none.
 
DETOUR

flatgrinder said:
I just purchased a SOG Trident, excellent knife! Scored it for $50 off ebay. And the ARC lock has been tested to hold 1000lbs! :eek:
Click to expand...

Just for the records, the Trident is NOT an "Arc Lock", is an "Arc-Actuator". Is a very different animal, believe me, I opened both :)

lorise said:
Does your Trident have blade play? Mine does.
Click to expand...

Mine too, it was a huge disappointment. The Arc lock on my Pentagon-Elite II on the other hand is excellent.

BACK IN TRACK

O.K. you can keep discussing frame locks :p


BETO
====================
Sorry for my english :o
 
You must log in or register to reply here.
Back
Top