Spine taping a lock to induce lock failure?

I have spine tapped.
My daughter in-laws go garage sailing and pick up cheap knives and bring them to me to sharpen and give a once-over. I take the liner locks and give them a few tap/whacks on a 2x4. Nothing extreme. If the lock fails or looks like it could it goes in the trash.
Nothing extreme.
 
The typo in the thread title led me to believe, that somebody had invented a novel way of testing knife locks.

IMO spine whacking/spine taPPing is a superflous exercise and of no use to the vast majority of knife users.

Leo3an said:
Then there is a no need for a lock. Just a friction folder is good enough.
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Thats a broad statement.

Good enough for what?
 
I had American made bear and son liner lock, Rat, and a slew of locks that within a few months would fail a spine whack from striking back of blade on my leg. Then one day I said enough and went with a Cold Steel entry model Finn Wolf and 3 years later no failure of lock.
 
Cold Steel/Ontario fanboy said:
The thing I noticed on my RAT and Bear and Son liner lock on closer inspection was the blade itself where it meets the lock was ground down and worn in a 45 degree wear parrern.
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That is exactly what someone should look at BEFORE purchase. You can eyeball it and tell lock slippage will happen whether it is safe or not.

people are so worried about having an early lockup.. Sometimes a too-early lockup adds to the issue and then people spine whack the blade cause galling and almost guarantees more lock slippage. I feel sorry for the knife makers sometimes because of the pressure for early lockup by consumers. They try to match the blade to the liner and sometimes that means they make the blade tang to steep. All this because of the internet pressure for blades with early lockbar lockup.
 
I even had 2 Kershaw half tons develop the same problem. I value a strong lock above all else and opening landscaping bags I cannot afford to have a blade slip and lay my hand open. Some say carry a fixed blade but some people I do work for are very spooked of seeing a fixed blade on my side especially when I am 6'3 240 lbs and covered in tattoos. So after research on youtube for lock strength I went for a Cold Steel Finn Wolf withTrii Ad lock up. It is a cheaper intro model but I must admit for a general work knife it does the job and have yet to even experience blade play or lock failure. I wanted a Spyderco or Benchmade but I cannot afford $200 bucks for one right now. And I quit Bucks since they changed their blade steel to 420.
 
Any tool will fail if used in a way it wasn't designed for. I don't understand people who try to break a tool and then complain it failed.
 
Maybe since I started using folding knives before the locking blade was invented makes me less concerned ? I dunno but if a blade locks up tight with no blade play, I'm good to go. :)
 
Personally, I hit the spine pretty hard on the palm of my hand. I'm not sure if this is legit spine-whacking or if I'm being too gentle with my knives. This is what I do every time I buy a new knife. Even before that, at the store, before buying, I will already have pushed on the spine a bit to feel for its robustness, of course without any of the staff looking... So far I've never had lock failure, and if I did have one, I wouldn't use that knife anymore. It's not about improperly using a knife (I grew up with Swiss Army knives so I know how to use non-locking knives safely), it's for just in case I'm cutting something particularly tough and accidentally hit the spine on something hard. I want to know my knife can handle it.
 
eugenechia1989 said:
Personally, I hit the spine pretty hard on the palm of my hand. I'm not sure if this is legit spine-whacking or if I'm being too gentle with my knives. This is what I do every time I buy a new knife. Even before that, at the store, before buying, I will already have pushed on the spine a bit to feel for its robustness, of course without any of the staff looking... So far I've never had lock failure, and if I did have one, I wouldn't use that knife anymore. It's not about improperly using a knife (I grew up with Swiss Army knives so I know how to use non-locking knives safely), it's for just in case I'm cutting something particularly tough and accidentally hit the spine on something hard. I want to know my knife can handle it.
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I just bought a new ZT 0450cf with a VERY early lock-up. I tried to close it (having my fingers out of the way) with the lock engaged and "whacked" the spine on my hand. Rock solid but I always keep an eye on the lock on all my knives anyway.
 
Better to know, than not know, and have an accident that gets stitches. I know, some people have been around since ww1 and never had a lock failure lol Congrats you're the greatest knife user on earth. Guess what, billions of others use knives and aren't as super talented to avoid an accident forever.
 
I've never understood the vitriol against moderate spine whacking to test a lock. Locks were designed in the first place to guard against accidental, unintentional closure of the blade and yes, that can and does happen - including impact against the spine. Locks should lock, period, until intentionally released. A lock that fails against moderate stress is either a faulty design or shoddily manufactured. Either is good to know.
 
colubrid said:
That is exactly what someone should look at BEFORE purchase. You can eyeball it and tell lock slippage will happen whether it is safe or not.

people are so worried about having an early lockup.. Sometimes a too-early lockup adds to the issue and then people spine whack the blade cause galling and almost guarantees more lock slippage. I feel sorry for the knife makers sometimes because of the pressure for early lockup by consumers. They try to match the blade to the liner and sometimes that means they make the blade tang to steep. All this because of the internet pressure for blades with early lockbar lockup.
Click to expand...

It can be the spine whacking which causes the lockface to “dent” at a weird angle. The contact area between a frame or linerlock and the tang is very small and easily damaged. For example the lockface on my Super Roadhouse seems to have been damaged somehow and is now slipping. With Canadas’s new stupid import laws I would have to ship it to an friend in the states to send it in for repair for me.

I test for lockslip by pushing hard on the spine of the blade. I also agree a few spine taps is likely fine but spine whacking is dumb.
 
Lapedog said:
It can be the spine whacking which causes the lockface to “dent” at a weird angle. The contact area between a frame or linerlock and the tang is very small and easily damaged. For example the lockface on my Super Roadhouse seems to have been damaged somehow and is now slipping. With Canadas’s new stupid import laws I would have to ship it to an friend in the states to send it in for repair for me.

I test for lockslip by pushing hard on the spine of the blade. I also agree a few spine taps is likely fine but spine whacking is dumb.
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A knife designed for self defense, should handle a random shock against the spine. Considering what can happen in a fight is completely unpredictable. I don't see how you could disagree, unless you believe in a fight nothing could happen causing the back of your knife to hit something hard..like the side walk if you ended up on the ground, or any one of a million things.

This pertains specifically to knives designed as weapons.
 
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