Question for Jimmy concerning omega springs

Jimmy -

Regarding broken Axis Springs, which I no longer experience, I was 2x told the following, from two different Benchmade sources. Is the following in accordance with your understanding or opinion:

For proper usage and optimal, or perhaps perpetual longevity, both sides of the Axis Lock's protruding barbell are designed and intended to be simultaneously "pinched" between two (2) fingers and pulled down applying equal pressure to both sides of the Axis bar, in unison.

Whereas, pulling down and applying pressure to only one (1) side of the Axis bar with one's thumb or other finger, subjects Omega Springs to undue stress from the excesssive force of unilaterally shouldering a burden that was instead designed to be shared and balanced by both sides of the Axis bar.

Thanks!

If you apply pressure to one side of the axis bar (lock stud) you will need to pull that side down a little farther than necessary to disengage the lock. This could result in slightly higher stress on the side that is being pulled and slightly less stress on the opposing side. Realistically though the difference is minuscule especially if you compare to using both fingers and pulling the lock stud all the way to the rear every time. In other words it doesn't really matter.
 
If you apply pressure to one side of the axis bar (lock stud) you will need to pull that side down a little farther than necessary to disengage the lock. This could result in slightly higher stress on the side that is being pulled and slightly less stress on the opposing side. Realistically though the difference is minuscule especially if you compare to using both fingers and pulling the lock stud all the way to the rear every time. In other words it doesn't really matter.

Thank you so much for saying this! People hear and other places are saying BM techs told them the springs were going to self destruct if only one side is pulled. They all talk of over stressing the one spring. As you so clearly state, normally they both get maxed out when you close the knife with both fingers. One spring isn't unilaterally doing anything. If pulled back with one finger, then that side will likely max out and the other side wont. It doesn't matter though because the springs are designed to go back that far. You simply can't pull it back far enough to get to plastic deformation, the cutout wont allow it. Eventually they break, all things wear out. Think of the fail curve. Many of the flaws fail early (people breaking one in the first few weeks/months), then you get a long term of relatively few fails, finally the miles add up and any mega cycled spring wears out after decades or more. I've never broke one, despite my opening method, but wanted to make some. There are threads on this. I made some for my 810 and 940. It was easy and I couldn't tell any difference. I put the originals back a month later confident this issue is dumb.

For those told about the one finger no no... I assume that's a standard response to the why did my spring break question. You know, like the did you unplug it line.
 
I'm also wondering then, why springs, such as in a firearm, should be replaced after so many rounds fired.
First of all I admit to being a complete incompetent when it comes to fire arms. I've shot a few times but that's it.
But
knowing the world as I do . . . I would guess . . . because it makes the gun manufacturers money. ;):)
 
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Therefore, it would seem that the metal fatigue should be due to a defect in the metal of the spring.

However, using your valve spring example... under high stress, many race car teams, i.e. in NASCAR, replace their valve springs after every race. I was asserting that overuse of the Axis lock mechanism might be considered higher stress, but after reading about endurance limits, I see that that might not make sense. I'm also wondering then, why springs, such as in a firearm, should be replaced after so many rounds fired.

Here's some info on preparing high stress spring material
Pre-stressing.
Springs are normally pre-stressed by scragging, in which the spring is compressed until the
stress in the outside fibers of the wire is greater than the yield stress of the material, causing
plastic deformation of the outside steel fibers. This induces residual stresses so that the yield
strength of the steel is raised.

Shot-peening.
Springs are provided with a short-peening treatment, which considerably improves the
fatigue strength of the steel. During treatment, the spring is bombarded all over with round
particles of hardened steel (shot) at high velocity. This produces compressive stresses in the
outside fibers of the coil wire. These residual compressive stresses help to prevent tensile
stresses being developed on the surface of the wire. But, if any imperfection exists in the outside
fibers of the wire, such tensile stresses initiate crack propagation leading to fatigue failure.

Of course that would add fifty dollars to each knife if that was done to Omega springs. Probably not worth even thinking about.

As far as the race car springs. I'm guessing but due to elevated temps above autos driven on the street in a more sedate environment and the engine speeds at least two to three times the average speed of street driven autos the springs get beat up pretty good. The steel looses some of it's temper and the coils colide together from over speeding (red lining) the engine. You'd get a little tired to if you were one of those springs. If I understood correctly they loose some of their spring rate (compress and soften) rather than break.
 
If you apply pressure to one side of the axis bar (lock stud) you will need to pull that side down a little farther than necessary to disengage the lock. This could result in slightly higher stress on the side that is being pulled and slightly less stress on the opposing side. Realistically though the difference is minuscule especially if you compare to using both fingers and pulling the lock stud all the way to the rear every time. In other words it doesn't really matter.

When using only one side of the stud, the spring is also slightly twisted and pushed inwards and can also rub against the liners.

I just started reading up on several cases of broken omega springs. Some of them looks like cases where the spring broke form "One Finger Pull"(hereinafter referred to as OFP).

On top of that, one of the springs on my two month old 556-1 broke a few weeks ago. And guess what.. It broke while I was playing with it using the OFP. And guess which spring broke? Yeah, the one I was pulling on..

In general my theory is that there are three typical cases of omega spring fails:

- Long time stress failure(should take several years, if ever).

- Corrosion on the spring.

- OFP

There also might be cases of failure from manufacturing, off course.

I'm gonna try to make my own springs from stainless memory wire, even though I have a set of spare OEM springs. I always thought omega springs breaking was kind of a myth, and then it happened to me.. lol.. :p
 
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I have several axis lock benchmades and had'm all apart. One of them, can't remember if it was new or used, or even which one it is, had a spring rubbing the liner. This was apparent from the shiny flat section on the inside of the spring, and rub marks on the liner. I tweaked the spring to not rub the liner and so far no failure. Might still happen since the spring is thinner, but it's surely prolonged now.
 
I had a 710 have a spring break twice on the same side. I believe it's rubbing the G10 lightly and it's wearing the spring down. It broke after a pretty considerable amount of openings. Estimated to be a few hundred thousand over a year or two. The centering is a bit off. Not taken mine apart in awhile but I've seen reviews of other BMs where people will report a shiny spot on the around the same spot I had mine break. I haven't had further problems, but I'm not working a job that affords me the opportunity to open a knife 150 times a day to use it anymore.
 
OK... I like conversations that teach me new things. I get that the endurance limit dictates infinite cycles now (after doing a little research). I do not know how BM tested their Omega Springs, but I'm assuming they have that in order. Therefore, it would seem that the metal fatigue should be due to a defect in the metal of the spring.

However, using your valve spring example... under high stress, many race car teams, i.e. in NASCAR, replace their valve springs after every race. I was asserting that overuse of the Axis lock mechanism might be considered higher stress, but after reading about endurance limits, I see that that might not make sense. I'm also wondering then, why springs, such as in a firearm, should be replaced after so many rounds fired.

First of all I admit to being a complete incompetent when it comes to fire arms. I've shot a few times but that's it.
But
knowing the world as I do . . . I would guess . . . because it makes the gun manufacturers money. ;):)

There is a definite degradation of springs in firearms with use. Most notable are recoil springs and magazine springs. While there are factory springs, and aftermarket high performance springs, they are all subject to loss of strength through use.
 
I haven't had an omega spring break on my BM's. However, it's my understanding that the more you use a spring,the faster it wears out.

I don't know the energy that is imparted on the spring each time the Axis lock is actuated. However, if you've ever bent a paper clip many times quickly, it heats up the bend point enough to burn skin, and eventually breaks. Although springs should resist this to a certain extent, I would assume that constant flicking (as in over and over, quickly without stopping, for 10-20 minutes at a time) might induce wear that might equate to decades of use. Just a theory.


That only happens if you exceed the elastic limit of the spring. If you don't overextend a spring it will last for an exceptionally long number of cycles.
 
Should omegas get an occasional spray of lubricant or protectant especially after getting wet?
 
The Omega springs are a stainless steel. A spay of oil wouldn't hurt but they should be fine as long as you let the knife dry out and it doesn't stay wet for long periods of time.
 
Ok cool! Thanks a bunch. I always dry them well but did recently clean some fish with a regular large grip and presidio 2 and were so gross had to hand wash em n sink! Lol
 
There is a definite degradation of springs in firearms with use. Most notable are recoil springs and magazine springs. While there are factory springs, and aftermarket high performance springs, they are all subject to loss of strength through use.

Thank you.
I'm a little smarter now.
 
The Omega springs are a stainless steel.
Excellent ! ! !
And we know how hard it is to remove a big flappy bur from the edge of a stainless blade. That sucker will flip back and forth for ever until you grind it off; meaning stainless springs should be pretty tuff.

I'm going to relax a little and wash my BM handles with confidence.
Thanks
 
Excellent ! ! !
And we know how hard it is to remove a big flappy bur from the edge of a stainless blade. That sucker will flip back and forth for ever until you grind it off; meaning stainless springs should be pretty tuff.

I'm going to relax a little and wash my BM handles with confidence.
Thanks
:p :thumbsup:
 
Got around to open my 556-1 and check where the spring broke.

It broke right in the U bend and looked like a stress break. Forgot to take a picture before it ended in the trashbin..

Here is my two new ones made from Beadalon Remebrance memory wire, not perfect but I think they will do the job. I will off course report back here if they are to break or have any other kind of failure.

Original at the bottom.

PAp3toN.jpg
 
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Had my first omega break on me in my 556. Right in the U with no signs of corrosion. Now I get to send it in for a spa treatment!
 
It broke right in the U bend and looked like a stress break.
This is really great that you posted about this; both of you. Thanks.

looked like a stress break
Will you be more specific ? Was the end splintered or was it cracked part way straight across and shiny(ish) part way across (probably take good magnification to say). Shame it got thrown away.

For some reason I thought the wire might be square in cross section (rather than round in cross section).
 
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