Question on Liner/Framelock Wear?

[Megalobyte]

As we all know, as a liner/framelock knife wears in, the liner will slowly start to move across the blade towards the right hand side. I always assumed that what was wearing and causing this to happen was that the face of the liner and the face of the blade, where they engage each other, wears slightly from friction, in effect, making each one slightly shorter, thus, since there is now empty space, the bend will cause the liner to move to the right to take up that slack. But, it occured to me that this might not be the case, rather, its not the liner/blade surfaces that are wearing and causing the liner to travel, but the stop pin becoming slightly bent downward from repeated impacts, which will also cause the liner to move to the right to correct for this extra slight amount the the blade will be higher than it was relative to the lock face.

So, to you makers or knife lovers who know, which is it, or is it both?

Thanks.

 

[KennyC]

now that its brought up, i believe it makes a lot more sense that the stop pin is bending instead of the blade/liner surfaces wearing(on good quality knives) if it was the blade/liner sirfaces wearing, would the pivot, the washers, wear alot faster than they do? after all, it would make sense that for every 1/8" the liner/blade rub on each other, the pivot has made at least a half circle, which depending on the knife could be up to 3/4" of traveled distance......hmmm...

 

[T. Erdelyi]

More the stop pin but it is both, some makers make a concentric adjustable stop pin to take up the slack.

 

[knifenerd]

Hmmm---Sounds like it could be a combination of both. If the knife is subjected to a large amount of hard "flicking", I'd tend to go with stop pin wear being the problem. Flicking shouldn't have much of an effect on the liner--but the stop pin will take a MEGA-amount of abuse.

 

[JDMSMBACPA]

I've read (here) that Chris Reeves hardens the face of the frame lock to minimize wear. Otherwise the harder blade would wear the softer face of the frame lock. That said, I agree with the "both" concensus.

 

[Matt Shade]

Its both, if you open the knife and pull the liner over like your going to close it, with a good light you'll be able to see that the blade is shiny where the liner meets it.
The reason the pivot/washers don't wear the same way is they don't have as much friction between them. The blade and liner have to "stick" in order to work, there's a reason we don't teflon coat the lock face The washers and pivot are made of materials that cause less friction (teflon, phosphor bronze etc.) and reduce wear, and they are designed to move in a manner that doesn't make them bind with each other. The blade and liner have to wedge to together and kind of "bite" in order to make a tight lockup.
And the stop pin can become dented/worn.
The tolerances your relying on are pretty demanding. The wedged shape of the lock face on the blade is pretty much agreed to be best if its milled to a 6-7 degree angle. That angle across a peice thats only .125" thick yields you .015" of wiggle room, and most folks won't buy a knife if the liner doesn't start out about 1/4 - 1/3 of the way across. Now your down to .0099"-.011" of room for wear
So when the liner moves halfway across after a couple years of beating on the knife, or incessant flicking, its not wearing nearly as fast as you think

 

[brownshoe]

In my experience with spyderco and benchmade liner locks, often the lock moves across the tang surface due to looseness in the pivot pin area. A moved liner lock due to this problem can be discovered by holding the liner over with one hand and getting side to side play in the blade w/o the liner lock touching the blade. Lockup is still good when this occurs. Often times an adjustment of the pivot pin with a little locktight can restore a liner to its original stopping place on the tang. As an aside, I believe that in the SPyderco forum, stop pins and liner lock materials and hardening were considered proprietary information by Spyderco. This would make one believe that this is critical to reliability.

 

[cpirtle]

Originally posted by brownshoe
In my experience with spyderco and benchmade liner locks, often the lock moves across the tang surface due to looseness in the pivot pin area. A moved liner lock due to this problem can be discovered by holding the liner over with one hand and getting side to side play in the blade w/o the liner lock touching the blade. Lockup is still good when this occurs. Often times an adjustment of the pivot pin with a little locktight can restore a liner to its original stopping place on the tang. As an aside, I believe that in the SPyderco forum, stop pins and liner lock materials and hardening were considered proprietary information by Spyderco. This would make one believe that this is critical to reliability.

Well said and I agree completely. Except sometimes you can have little to no lateral play and still need to tighten the pivot a little, this is more common on the silicon based washers.

Most stop pins are hardened and I really can't see much chance of them getting malformed unless the person is a flicker, then it could certainly be more possible.

With Titanium locks galling is probably the biggest reason for lock wear (aside from the loose pivot), when the lock galls the tang it will scrape material away. Another culprit would be too much tension on the lock bar itself.

Just my opinion..