FRN handles & "tired" locks

E

edison

Joined
Jun 20, 2004
Messages
174
What are the symptoms that tell you to replace your knife (or turn it into a trainer...) .....how much blade play is acceptable when the blade is locked out?
 
This is a tricky question to answer without being able to examine the knife. Get the answer wrong and somebody may get a severe injury. A small amount of blade play can be OK, or it may indicate a mechanical problem. If there is something abnormal about the lock (tired?), that can be a safety issue, too. If you have any doubts whatsoever about the knife, you should have it inspected by the manufacturer or some other competent person. Maybe the owner of a local knife shop, for example. There are plenty of people on this very forum who have knife injuries that have never completely healed. It's not worth taking a chance on the knife failing in use. FRN knives are usually inexpensive enough that replacing them is not a problem and getting a new knife is always fun.
 
edison said:
FRN handles & "tired" locks
What are the symptoms that tell you to replace your knife (or turn it into a trainer...) .....how much blade play is acceptable when the blade is locked out?
Click to expand...

What part of your question did FRN play?

Can't answer your question on blade play. None of mine has ever developed "excessive" blade play, so I don't know when I would retire one.
 
If a wobbly lock passes a spine whack test, its good enough for me. Although I use the edge of my blades 100% of the time so I dont get all the "super strong lock" requirements. Don't get me wrong, I always make sure the lock on any knife is working properly and sits secure but if I was doing any work that required a super strong lock, Id use a fixed blade.
Just my 2 cents.
 
knarfeng said:
What part of your question did FRN play?

Can't answer your question on blade play. None of mine has ever developed "excessive" blade play, so I don't know when I would retire one.
Click to expand...

I guess my real question is "when is up & down blade play" considered excessive. My thought is FRN (no metal liners) wears more quickly aroungd the pivot (or could be distorted more easily) than brass, etc....
 
Lurker said:
The answer to this question is "when it is bad enough to post a question about it on the internet."
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:p
Well, I was hoping for something a little more "quantifiable"! For example, even the MBC Spyderco's have some blade play and it is considered normal (if I remember some post's from Sal correctly)...so how much is excessive?
 
Playing with a Spydie Tasman Salt w/FRN scales that I use probably every day (just opened-up a box ~4 minutes ago), it shouldn't have any 'up and down' play at all because the locking parts are steel-on-steel. The lockback that runs thru the entire spine of the FRN is both pinned and wedged into place so to form at least 2 additional areas of support to the extended blade.

If you have anything to worry about, it may be lateral loosening over time, something all folders are susceptible to.

Do you really have a folder that is worn, or is this just a theoretical question?
 
I don't think FRN knives are any more prone to vertical play the other handled knives.

Otherwise anything that's visible, perhaps, >1mm I'd consider getting rid of.
 
edison said:
:p
Well, I was hoping for something a little more "quantifiable"! For example, even the MBC Spyderco's have some blade play and it is considered normal (if I remember some post's from Sal correctly)...so how much is excessive?
Click to expand...
It might be possible to get someone to answer this question, but you still have not posted the exact model of knife that you are worried about and as was mentioned above, a certain amount of blade play might be OK in one case, but might indicate a mechanical problem in another case. So, if you are not willing to have your specific knife examined by an expert, the real question is, "do you feel lucky?"

Another pertinent question might be, "do you need 10 fingers in your line of work?"
 
I would check for play when partially open. In fact, I have done this before. If you use a knife hard, the nylon can deform at the blade pivot, perhaps even the lockbar pivot. that little bit of wiggle is annoying, but I haven't experienced lock failure.
 
best solution: send it back to the manufacture and see if they recommend it be retired..... generally for me on a lockback, when open(locked) if you push the blade towards closed and a piece of paper will fit in the gap between the lock and the blade tang it is way past its prime
 
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