GEC farm and field problem

[knifeswapper]

have a GEC farm and field model lockback which i love . my problem is when the blade is open and i try to close the blade , the finger lock wont depress down . its extremely hard to depress and close the blade . is this normal for this type of model ? or should i sent it in to GEC ?

I expect the answer to the original question is subjective. I have had many lockbacks over the years returned because the release was "impossible" to disengage; and I had no problem with them. And I have a machinist buddy with fingers made of some type of iron, that laughs at me when I have trouble with the tightest of them. But if it is a problem for you, send it to GEC and ask if they can lighten it for you. You are the one that the knife needs to work for....

 

[esnyx]

Not a stretch...a fact Mike. No matter how you slice it, the spring is pinned in two places and the tang has contact with the spring on opening and closing the blade just like a non-locking traditional. Simple mechanics my friend.

The mechanics of a slipjoint and the mechanics of a lockback are quite different. If the only differences were the notch on the spring and the tang, and everything else was the same, the knife would be impossible to close once opened, hence the lockback. If the spring were one solid piece, as in a slipjoint, there would be no way to depress the backspring to relieve the tension on the blade, as you would just be pushing on a solid spring that is pinned on both sides of the point in which you are applying pressure. The spring tension in a lockback does not come from the lock bar, but rather a spring that is applying pressure to the bar on the side opposite the tang. That is how you are able to depress the bar and disengage the lock.

 

[rma100]

I expect the answer to the original question is subjective. I have had many lockbacks over the years returned because the release was "impossible" to disengage; and I had no problem with them. And I have a machinist buddy with fingers made of some type of iron, that laughs at me when I have trouble with the tightest of them. But if it is a problem for you, send it to GEC and ask if they can lighten it for you. You are the one that the knife needs to work for....

:thumbup: :thumbup:

 

[Markesharp]

And lack of snap is inherent in the design because a lock back knife has a lock bar mechanism, not a back spring as in a slip joint knife.

So, there is NO backspring like there is in a slip joint?

 

[ea42]

Not all lockbacks have integral components like the GEC's, but rather separate pieces that get the same results (but require more finishing operations). You have a butt piece, which is at the tail end of the knife and is pinned in place. Attached to this is a flyspring which exerts pressure on the lockbar to the rear of the center pin. The lockbar is actually a fulcrum in this case rather than a spring. The flyspring presses against the tail end of the bar, causing the bar to press against the tang. If you press against the "trigger" end of the bar, you release the tension on the tang, which allows the blade to flop around freely if you hold it in. This by the way is an easy way to judge if the blade is pinned too tightly. First depress the lockbar, If the blade moves fairly freely, it's fine. If you need to exert a good deal of pressure on the blade to pivot it, it's too tight. You can't pin these knives as tightly as a standard slippy due to the very nature of the weaker spring action. The fact that you need to be able to press that bar in (plus the general design of a spring against a pivoting bar), results in this kind of setup generally having far less tension than a normally sprung knife. Not being able to release the bar when the blade is locked open is often due to the bar jamming against the lock notch in the tang. Taking a very small amount off the end of the bar usually relieves this, as does relieving a bit of the flyspring tension. Removing the material does have its perils, there's a VERY fine line between having it too tight and winding up with a rocker. Sometimes a very slight wobble can't be avoided.

In a regular slipjoint knife you have a backspring that, due to the location of the center pin, exerts a good deal of pressure on the blade tang which results in your walk and talk. There is spring movement forward of the center pin, but the back is completely stationary, which anchors the spring in place and makes it perpetually sprung.

I hope all this made sense, pretty much echoes what Mike said several posts back.

Eric

 

[Alnamvet68]

Well, I'm confused (it doesn't take much), but what exactly happens when one receives a new #99 that apparently is in working order when received, then develops this lock problem; what exactly occurs for this to happen?

 

[MercyfulfateXX]

great thread. love learning stuff.