Please help me to understand Blade Play

E

edrozen

Joined
Mar 2, 2000
Messages
365
Hello. Wow, I've had a lot to talk about lately. Okay, whatever. Recently, my SOG vision developed a vertical play. I was wondering a few things about this annoying phenomemon.
1) Is there anything I can do to prevent a folder from getting play?
2) Are certain types of lock more prone to develop blade play. (Liner locks seem to be the worst, right?)
3) How could manufactures or custom makers build folders to eliminate play?
4) Are any knives "play-proof" or will most folders develop play over time?
5) How is horizontal play mechincally different from vertical play? (vertical play seems to come first)

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EdRozen-On the cutting edge of finding out what the cutting edge is....
 
I am no knife expert by any means so correct me if I am wrong.

From what I know, horizontal play can usually be fixed if the pivot is tightened, but verticle play usually can't be fixed. Liner locks usually develop blade play first because in order for them to lock solidly, very tight tolerances are needed in order to make sure the liner slides perfectly to lodge the blade in place. Manufacturers simply just need to fit liners more carefully by inspecting them and having more precise machinery. I am pretty sure all blades that require friction in the lock will all eventually wear down, especially liner locks. And from my experience, verticle play is caused because the liner is not long enough to fully lodge the back of the blade so there is open space allowing the blade to slide back and forth.

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A real knife collector is always broke.
 
Is this right?: From what I have noticed a lot of makers make the bottom end of the blade slightly angled. That way even if the liner does wear down a little the liner will still rest against the bottom of the blade. On my Vision, the liner has slid all of the way over.
 
That's why you have play, then. The angled area is there to account for play, but if the liner is all the way over, then you have used up all of that tolerance. (I think all liner locks must have this to work, but I'd be interested if anyone has one which doesn't) Like David said, horizontal play is due to a loose pivot, so just tighten up the pivot.

As for wear-resistant designs, integral locks have thicker 'liners', so the wear resistance is greater. Same goes for Elishewitz's 'bolster lock' (go to http://www.knifeoutlet.com and take a look; I could never figure out exactly what the lock was until I saw the picture they have over there). The Axis lock should be very resistant to wear (but I haven't had mine long enough to really state for sure). REKAT claims that the Rolling lock is resistant to wear, but I haven't taken a close look, so I have no opinion on that.

Hope this helps.

--JB

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e_utopia@hotmail.com
 
I am VERY picky about blade play.

I assert that a well made liner lock will NOT develop blade play even through vigorous use/abuse.

How can I make this assumption/statement?

That is easy, I have the proof clipped to my pocket.

My Benchmade CQC7/970 was the one I picked out of the 8-10 that were in stock.

After about 10-15 minutes of pulling twisting, snapping and flipping all the knives available - I selected this one.

It has held up to saltwater exposure, yards of cardboard, string, tape, paper, wood, plastic, cordura and webbing millions of snap-open presentations.
I open it 90% of the time by snapping it open.
It was even dropped FOUR FEET onto Concrete!

The tip got chipped but it is STILL as solid as the day I bought it more than ~4 years ago for $79.95 + tax.
This was back in the day when BM knives were scalpel sharp out of the box - this baby would catch on a standing strand of hair and cut it!

Course, it doesn't quite do that now but I am limited to how sharp I can get it...

BTW - the linerlock is only 45% of the way across..I don't think it has worn any at all.


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RKBA!
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Geeeze. 4 years, and its not even started wearing out to half way across?

-Chang the Asian Janitorial Apparatus
 
As stated, liner wear is usually the first cause of vertical play.

The other major cause is the stoping pin. Usually it's because the pin became lose in it's socket or get deformed from heavy use. A common cause of deformation being soft stopping pin. A large, fully hardened steel pin is best.

[This message has been edited by tallwingedgoat (edited 04-30-2000).]
 
edrozen:
Another possable problem could be that the liner lock does not have enough bend to accomidate the wear,"solution" take the knife apart if possable and bend the lock a little more but not to much because the lock will start sticking and wearing more quickly if it has to much of a bend.

I have a Kershaw Random Task that had this problem,the above fix took care of it.

Kevin
 
In my experience Lockbacks seem to develop vertical play more often than Linerlocks. May be its just been my luck but I have not had any linerlocks wear out. My Spyderco Walker is close to the far side but not there. It has been this way for a long time so it may have "stabilized" there. I have more lockbacks than linerlocks.

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Roger Blake
 
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