Real vs. perceived strength of various locks

Joined
Nov 16, 2002
Messages
9,948
I keep hearing about how strong the axis lock and integral framelocks are, but how strong are they compared to linerlocks and lockbacks? While I hear that the axis can withstand 210 pounds of pressure, it's never said whether that's just with the 710 or with every axis locked folder. I love my 921 Switchback to pieces, but I think that 210 pounds against it would smush it and its lock to pieces. While some liners will disengage under certain situations, Cold Steel's leafspring liners (like in their Scimitar) seem like they only fail from load instead from twisting.

How much of this is just repeating printed word versus actual experience?

For the record, my favorite locks are the axis lock and lockback, but then, I'm a lefty and don't want to pay through the gills for a lefty liner.
 
thombrogan :

While I hear that the axis can withstand 210 pounds of pressure...

The full statistic I have seen is something like "... more than 200 lbs of negative pressure". This sounds pretty fancy but is complete nonsense. It would be like asking someone how much a knife weighed and they answered "the mass is -3 inches". Lock strengths should be quoted in torque, in.lbs or ft.lbs .

Even then, when the numbers are provided in a meaningful manner (which is rare) you need to realize that this is a slowly applied load which is completely perpendicular. In actual use loads are likely to be sudden, and accompanied by twisting and side torques and those really strong locks will now fail much easier.

I have broken the lock an Arc Lock by SOG under light impacts and a Buck/Strider folder under light prying with a side twist. Both of these folders claim very high torque break points (and I don't doubt it), yet this translates to little actual functional strength.

-Cliff
 
As Joe Talmadge often points out strength is rarely the issue. The lock needs only to be stronger than your grip. As long as the lock can maintain itself through the efforts supplied by the hand, it is strong enough.Anything stronger is superfluous. Fun to talk about and such, but not any more useful.

Cliff's point is good too, but it goes hand in hand with Joe's reason for the earlier statement. Lock reliability is the key. And again, the lock only needs to be reliable just past the limit of the hand's ability to stress the lock. More is superfluous, but fun to talk about and such.

Phil
 
I personally wonder how important lock strength is to the average person. Before I became a knifenut, I waded through life with just a stockman in my pocket, which is just a slipjoint. I never had the blade accidentally close up on me. If I needed something stronger, I grabbed a fixed blade.

I pretty much think of a lock as just a security feature against an accidental slip with the knife. I don't count on any lock to magically transform a folder into as a fixed blade. That's just asking to lose a finger.
 
I pretty much think of a lock as just a security feature against an accidental slip with the knife. I don't count on any lock to magically transform a folder into as a fixed blade. That's just asking to lose a finger.

Exactly. I can't remember ever having a folding knife, locked or not, fail/fold under normal cutting usage. I have had them fold on me while trying to use them as awls or prybars.

There are some schweeeet small fixed blades out there these days. If you need that kind of strength, you can find a fixed blade knife that can be used as an EDC (Anso anyone??).

I expect this thread to be hijacked by the sharpened prybar crowd complaining about lock failures while fighting off hotentots in downtown DC.

Chris
 
I have never had my SAK non-locking slip-joint close accidentally on me.

This is probably because I know the blade is non-locking so I exercise the requisit caution.

One should exercise the same caution when using any locking knife.
But there is the good possibility of a false sense of security - and being over reliant on the locking mechanism.

Although the previous posts about locks being just able to withstand the pressure exerted by the hand sounds very sensible -

There are occassions when more pressure than the hand alone can be exerted -
like leaning one's weight into the cut, or heaven forbid pounding the knife with a tool or hand -
these could easily exceed hand pressure, and although not recommended - may well be "legitimate" under emergency situations.

My unsupported/unfounded impressions are that the frame-lock as examplified by the Chris Reeve Sebenza at the top end, and the Kershaw Vapor at the lower price end are inherently strong.

The Axis lock look to be strong but much depends on the roll/axis pin and the slot (in the liners and handle) it travels in.
 
Buzzbait :

I personally wonder how important lock strength is to the average person

Stronger and more reliable locks on folders allow them to have a wider scope of use which would benefit anyone who has beyond light duty cutting tasks

If I needed something stronger, I grabbed a fixed blade.

If you can carry a fixed blade, there is no reason to be carrying a folder.

That's just asking to lose a finger.

Or a functional lock.

-Cliff
 
I dont worry much about it anymore. I carry SAKs alot and of course they usually dont lock anyways. I do have one model SAK with a liner lock, but if it wasnt there I would still use the knife.

I did have a slip joint close up on me once. When I was a kid I swiped dads Old Timer Stockman. I decided I was going to cut open a tennis ball and kept stabbing at it to makes holes. Of course those knives are not designed for full force stabs and it finally folded up on me....still have the scar after all this time. Anyways, that was not at all a failure of the knife, rather just a dumb kid using a tool improperly. When used properly for imtended tasks, slip joints are just fine.
 
When we had only slip-joint knives we used them accordingly.
When it came to self-defense with a slip-joint, we naturally intuited the weakness of a slip-joint and we accepted the limitations of a pocket knife as a self-defense tool.

Then came the Buck 110, and all of a sudden we all had a genuine weapon on our belt.
Of course, it took two hands to open it, unless one recontoured the cam on the blade to allow it to swing open with an educated flip of the wrist.

Then came the liner-locks, which opened easily, and, along with the liner-locks, came the debate over lock strength.
Those who favored the straight-from-the-factory easy opening of the liner lock argued incessantly for the greater strength of the liner lock.
However, no one offered any proof either way.

The strength of the lock matters only for self-defense because in the heat of combat the knife may experience all sorts of unpredictable loads from every direction.

People buy these knives for an increased sense of security.
In the back of their minds they know that a folder will never provide the same security as a fixed-blade will, and yet they don't want to think about it or hear about it.
Therefore, when someone touts a lock, different from the one on their knife, they feel the need to defend the strength of their own knife's lock.

As far as relative strength goes, I think the stoutness of the components, in terms of both materials and dimensions, determines the strength more so than does the design.

As a left-hander, I look at the probability that the design will release the blade because it favors the right hand more than the left.
Additionally, as someone who prefers the paintbrush grip, I recognize that some locks, such as the axis lock, will release in that grip regardless of the hand used to hold the knife.

Therefore, I prefer the lockback for its complete ambidexterity.
Some people write that they can release a lockback by squeezing with the entire hand, but I have never seen anyone demonstrate this in my presence.
In any event, I choose between lockbacks on the basis of materials and stoutness.
 
Just random some thoughts...

With SAK's, I have a Rucksack which has a blade lock for the main working blade. So locking the blade obviously became an issue for the uses of that specific model. I have no idea if the other newer versions of SAK have that feature now, though. It has served me well over the course of time I have had it. People I associate with think it is pretty nifty when I take it out for little jobs or when I go hiking.

Based on the various positive reviews, I have an Arlee Niemi Megaladon on the way in the mail. The ability for a reliable lock approaching the strength of a fixed blade has always fascinated me. It may be wishful thinking for me to get one approaching the strength of a pry bar, although it has been a challenge for me to find one. I hope to have the Megaladon in my hands to examine in order to see if it lives up to it's rep. Since it is a custom knife, I will not be putting it through the Cliff Stamp gauntlet. I will leave those tests to the more daring of my bretheren.

I have very few folders. Most of my knives are fixed blade. However, for me, folders do have their appeal in that they are convenient. I don't rely on my folders to be pick axes or crowbars. They are mostly for everyday chores and are expediant for when I need something quick and expediant. They aren't meant for hard chores. In fact, I consider them to be throwaways, if the need arose. Maybe that is why I have a tendency to abuse my folders more than my fixed blades.

I haven't found the need to fight off hottentots with them yet... although the occasional Amish and Mennonite has come across my path. No problems so far.

For what it's worth...
 
I completely agree with the people who have expressed concern over putting all of your faith into a lock. I always treat a locking blade like it could possibly close just as I always watch my hand postion on a fixed blade and treat it as though there were not a finger guard wheter there is or not.

As far as lock strength goes I also tend to agree that I am much more concerned with how well it works in everyday situations than I am about manufacturers claims.

I am also more worried about the condition of the lock than the claims. I don't care what it was said to hold brand new after five years of service and wear it could easily contribute to a lesser load for failure? Yes I have had my Spydie Delica lockback fail on me. Is it a qc problem...no it has just been used for years and with the lock wear it has failed from excessive lint and once because I allowed a teflon containing lubricant to sit in the notch. Will my BM mini-stryker fail me even after five years of very hard service?It still has a solid lockup and hasn't failed me on its own but once in my front pocket a penny fell into the space and didn't allow the liner to engage. I am also aware that it also doesn't lock up in the same position that it did brand new...titanium (as well as all)liners wear.

Personally the biggest thing that I like about the Axis lock is that on knives with larger blades such as my 806D2 it seems to keep the blade or lessen the tendancy for the blade to touch the liner as I have seen on many different brands and sizes of linerlock knives. Would I take it a gut a deer with it? Probably not because of its inner workings I would probably rather not subject it to the possibility of gunking it up making the chance for it to not solidly lock up greater. I will probably keep that job for my fixed blades.

With all of that written I guess what I am really trying to say is that I am more concerned with awareness to the wear, condition and external variables (lint, change etc..) of the lock than anything else.
Since having my Spydie fail I routinely check on the lint build up ecery time I sharpen any knife (which is often) and always check the lockups of all my knives after lubricating. I think that our general tendency is to just whip out a knife and go to use but a second of observation can prevent bones from ever seeing sunlight(personal childhood experience:D )
I think what we should teach newbies isn't strength claims but proper inspection when buying and proper lock maintenance.
Just my $.25 worth
Travis

edited due to mistakes
 
I almost get it!

So mentioning the strength of various locks, especially the new and exotic ones, are a way of saying "were you to use this pocket knife in a life or death situation, here's a reason to feel a little more secure (assuming nothing went wrong during manufacture)" and "this knife will cut, chop, pry, pierce, and even lift your car off of the ground so that you may use it to change a tire even though we'll void your warranty if you so much as whittle with it because, after all, it just isn't a fixed blade".

So the bottom line to the lock debate might be:

"As long as it doesn't disengage during use and is slightly stronger than your hand strength, buy the ones you think are the neatest"

or

"Buy a fixed blade for fixed blade work and a slipjoint for slipjoint work and find out how to sell off those non-essentials without taking too much of a bath".

And I could be wrong there, too.

Thanks, everybody!

Edited to add:
Travis,

My father-in-law let me in on the lint secret so I cotton swab out my EDC's every so often. The first time I did it was after carrying a lockback for almost a year. May I just say :eek: ?
 
1- I've had a SAK slipjoint fold on me (close call) while cutting through thick cardboard. The blade got hung up and in trying to pull it out, it closed. Luckily I had a good grip and it didn't fold up on me.

2- It's not legal for me to carry a fixed blade.

3- I've seen (and heard enough reports) of a linerlock collapse under palm pressure -- the same as might be experienced while trying to pull a firmly-wedged-in knife.

I don't want to be in a position where I have to cut something thick and dense and have my so-called locking folder collapse. I don't pry or scrape or what-have-you.

-j
 
While I think lock strength is important, I do think (as phatch said) that the importance of lock strength is often overblown. It's a fun thing to talk about, but even a well-done lockback or liner lock will be very very strong.

Now, it should excruciatingly obvious to anyone who has read my incessant blatherings on the subject that I feel that lock reliability definitely is of utmost importance and always worth discussing. While I believe that it is possible to make an extremely reliable lock using any of the popular lock formats (lockback, framelock, liner lock, etc.), I also firmly believe that some lock formats require closer tolerances and are more sensitive to minor geometry changes, and as a result are much more difficult to consistently[/b] manufacture to be super reliable. I've seen some formats that seem to auto-disengage in disturbingly high percentages, I've seen others that are really susceptible to pocket lint, etc.

Joe
 
As a good rule of thumb I think one should treat locks on a folder like the safety or slide lock on a firearm... it's nice to know it's there although take caution while handling and using it. Don't absolutely rely on it since the possibility of failure is possible. I think taking reasonable safety pre-cautions is prudent when handling anything that is potentially hazardous. For what it's worth...
 
I rarely worry about it either because I use the sharpened side to cut stuff. :D :D
 
Locks can fail very unexpectedly. I recently had a small folder with a lockback fail on me while trying to cut free hanging manilla rope (3/4 inch). That should not have happened, but was a good wake up call.
 
Originally posted by Burchtree
I rarely worry about it either because I use the sharpened side to cut stuff. :D :D

Burch, I know you're being light-hearted, but to be serious, there are plenty of people who thought they would only use the sharpened side to cut stuff, who ended up with lock failures or stitches. If you use your knife for anything beyond opening mail and cleaning your nails, you will end up torquing the blade at some point or other. Even doing simple things like gardening or breaking down boxes, blades do get stuck in stems or cardboard and need to be wiggled out. And if you're thinking about possible defensive use, obviously the lock can see all kinds of odd stresses.

Anyway, I point this out because a lot of people feel that a lock should be considered only a safety, and others imply that that you're using the knife "improperly" if there's any stress except from edge to spine (not to imply you said that, but others have). But in fact, I feel that both views are unrealistic for anything but light use. Luckily, there are locks out there that are both strong and reliable, and don't have to be babied.

Joe
 
Originally posted by LizardKing
Stronger locks are better locks

But what good is an otherwise strong lock that becomes dangerously easy to disengage, say, with a bit of oil on the mechanism? I've been cut by a good knife with a very STRONG lock this way.
RELIABILITY(predictability) is the name of the game.

Originally posted by UnknownVT
The Axis lock look to be strong but much depends on the roll/axis pin and the slot (in the liners and handle) it travels in.
Imo, It's a good thing to have the strength limit of a lock based on concrete data, ie how thick liners and lockbars are and such as opposed to how well a lock is machined or how much microscopic wear it has. A 90 degree contact point on the Axis lock allows strength to be based solely on material strength instead of the more subjective measurement of how well a lock is made.
The Axis provides a nice balance of things that a lock should do. Nevermind ease of use, but As far as great strength/reliability balance, one of the main ones being that perfect 90 degree angle at the point where the tang contacts the bar, there are no forces at work trying to push the locking bar off the tang as in some other designs. This single advantage will become immensely apparent when oil or something similar gets onto these crucial surfaces of certain other designs.
Just my .02
 
Back
Top