When would a spine whack EVER be necessary?

[GaryC]

Love non locking folders, to me it seems a lot of folks think a lockblade won't close. Like I said if it folds it may close. Treat all folders like slippies. GC

 

[stabman]

Love non locking folders, to me it seems a lot of folks think a lockblade won't close. Like I said if it folds it may close. Treat all folders like slippies. GC

I treat locking knives like they lock open...because they do.
I just don't buy crappy knives with unreliable, crappy locks.


And I still have all my fingers...weird!

(still say the spine-whack test is stupid though)

 

[Danke42]

Could go with a icepick etc. punch, something like that.

Or maybe it's just down to to technique.

 

[Insipid Moniker]

Just apply hand pressure on the back of the blade.
Controlled, and doesn't do stupid wear and tear on the lock for no reason.

Oh, I had a knife that passed spine whacks but failed the hand pressure test; haven't had any that were the other way.

Oh, and don't buy crappy knives; that solves most of the problems right there (the one that failed a hand pressure test was a crappy knife).

That's the test I typically use, but the one that failed most spectacularly was a $100+ titanium framelock. It was a good knife in just about every other way, but the lock would disengage with hand pressure.

I do, however, think that, given the significant difference between static and dynamic pressure, a properly executed, scientific spine whack test could really give us a lot of information. The idea that I've floated in the past that I'd love to see would be a modified Charpy machine. Secure the handle and drop the hammer on the spine of the blade. It would unquestionably destroy the knife, but unlike any of the testing I've seen so far it would give you a hard number of how much force the lock could withstand. That would give us an actual basis for comparison between different types of locks, different models of knives and even how common lock types from different manufacturers would compare.

The other neat thing about doing that is that you could take a common fixed blade, say, a Mora and break it the same way. I would be VERY interested to see what percentage of the strength of a fixed blade some of the stronger locking mechanisms on the market could approximate.

That's my big complaint with the spine whack test. I get the point of the test, but the methodology sucks.

 

[Insipid Moniker]

Could go with a icepick etc. punch, something like that.

Or maybe it's just down to to technique.

Or you could use one of the many hundreds of locking folders that will handle it just fine.

 

[ursamajor]

Please do demonstrate whacking the spine while withdrawing the knife from a confined space you were cutting in.

The last time this came up I really hoped to see an example of this but there were no takers.

Now at least in this thread we've got a real user who can show us how it's done. If you're worried about getting nicked tape the blade or use your trainer.

I just can't wrap my head around that movement. I've tried and tried but it won't happen.

I don't take artsy pictures of my knives with coffee or beer, and I'm not about to make a video reenacting when my non-assisted Kershaw Whirlwind failed on me back in 99 or 2000.

I will tell you what happened though. I used to subcontract appliance installs from Sears. Anyway I was working to remove an old dishwasher, that had its pump crap out. Anyway, I would I would first disconnect the power (this one had a pig tail wired in that was plugged in under the sink.). I then took the kick plate off, and raised up the legs as far as they would go, because it makes removal easier. I then unmounted it from the counter.

And finally we come to the drain hose (all the rest took less than 5 minutes). Well this drain hose was all dark rubber-not the ribbed plastic that you see in today's dishwashers. And it was attached to an air gap on the far side of the sink. But the hose was cut very short, and unscrewing the air gap and trying to pull it and the hose up to disconnect was impossible. So I had to climb under the sink. The way the hose and air gap were positioned way up in the cabinet, I had to clear everything out from under the sink, and then snake my way under the peatrap and disposal, hold my little mag Lite in my mouth, and reach up with a pair of channel locks to pop the clamp, and while squeezing it, pull it down the hose and out of the way. Then the knife part came in, because the hose was for all intents and purposes epoxied to the air gap with rotting waste, and would not pull down. The technique used to get past this, is to slice it length ways down the side/stem so that the hose ends up split. I did just that, and when I withdrew my hand, the blade hit the cast iron sink, and the lock failed, slicing my index finger to the knuckle. It was not even a swing. It was just the Force of me pulling my hand out.

I was holding the knife in a grip like this (you can see the 16yo scar from said injury right there), because I had to reach really high behind the sink and the rear of the cabinet.

That injury required stitches on the back of the knuckle of my right index finger. I am right handed. I missed 2 weeks of work from it.

Some people use their knives to do more than cut tape on packages, or take meticulously staged photos with their coffee. They are called knife users. And these knife users generally work with their hands. And when locks fail due to work related activities, these knife users sustain injuries to their hands, and those injuries result in loss of income. So to knife users, lock strength is important.

 

[Sosa]

This is when the thread is usually spammed and turns into a circle jerk.

 

[sideways]

I see nothing wrong with engineering a folder to stay open.

If it costs me nothing, why would it bother me?

 

[RX-79G]

I would be pleased if someone else wants to whack knives so I have a better idea what I'm buying. But doing it to your own knife is like testing your own Volvo's crash safety.

 

[AmosPaul]

It sounds like a lot of people want locks on their knives, but they don't ever want those locks tested. That makes perfect sense . . .

 

[pathwinder14]

It's not a test for the sake of the task.

It can be used to rule out poor lock face geometry.

For instance

When going for an early lock up,

If a spine "tap" makes the lock fail it's a sign of a poor lock face geometry, adjustment, fit and finish.

I'm not advocating extreme spine whacking but if I was a maker I would want to make sure my product didn't have any lock up issues

So...This is Spinal Tap?

 

[Lycosa]

Never.

 

[demoncase]

For me, the problem isn't that the spinewhack test is pointless- it isn't.

It's just it's part of the whole picture- not the whole picture...and certain manufacturers weight their "testing"* videos towards this area of the picture as they are strong in this area. Fair enough- folks making sportscars tend to pitch their advertising toward race track performance and gloss over the turning circle for parking at the supermarket.

I've never had a quality named-brand folder in the $60+ range ever fail when catching it against the inside of a wooden box or engine bay while cutting. Not once. Call it lucky if you want.
I've (on the other hand) hand no-brand liner locks fail when barely tapped, and was suitably wary.
I've had some lightly built sub $60 folders fail when attempting to cut something weight outside their original design parameters and getting them stuck. That's my own stupid fault.

The opposite perspective- to rephrase the OP's question a mite- is: "If passing a spinewhack test is what makes a pocket knife worthwhile, then how do they keep selling slipjoints?" #

*However: calling something 'Absolute Proof' from a non-statistically significant sample sized, non-repeated, non-double-blind experimental design is the kind of thing that gets you a F- in college....The plural of anecdote is not data. It's advertising, not science.

 

[jstrange]

^
Speaking of which, I haven't lost a moments sleep over lock failure, strength, or reliability since I started carrying slip joints. It's a huge relief to me and creates great peace of mind. More folks ought to try it.

 

[Insipid Moniker]

However: calling something 'Absolute Proof' from a non-statistically significant sample sized, non-repeated, non-double-blind experimental design is the kind of thing that gets you a F- in college....The plural of anecdote is not data. It's advertising, not science.

Strongly agree, with a few caveats. A. Anecdotal evidence is notoriously weak and imperfect, but it's still evidence. B. It's literally the best we have access to so it, rightly, becomes prima facie evidence.

To my knowledge, Spyderco does probably the most comprehensive testing of their knives of any company, but we don't have access to it. I respect Sal Glesser a huge amount, but I'd love it if consumers had access to that data, as it would be a tremendous step towards an educated consumer base. As is, all we have is enthusiast testing and the occasional Cold Steel video or Busse challenge demonstration. It's not perfect, or even that good, but it's all we got.

 

[Insipid Moniker]

^
Speaking of which, I haven't lost a moments sleep over lock failure, strength, or reliability since I started carrying slip joints. It's a huge relief to me and creates great peace of mind. More folks ought to try it.

Right now I have a Triad lock folder in one pocket and a slipjoint in the other. And, honestly, without access to all the data, if I wanted a folder that gave me the MOST protection from spine whacks? Probably a slipjoint with a very positive half stop.

 

[demoncase]

Strongly agree, with a few caveats. A. Anecdotal evidence is notoriously weak and imperfect, but it's still evidence. B. It's literally the best we have access to so it, rightly, becomes prima facie evidence.

I'm in violent agreement with you

And further- when the same anecdotes get repeated frequently enough (Thanks for that, internet!) things go all 'alchemy' and they get transmutted from 'anecdotal evidence' into 'received and unchallengeable fact'

 

[crom]

Could go with a icepick etc. punch, something like that.

Or maybe it's just down to to technique.

Because if you have a good knife with a reliable lock, you don't need to stop what you're doing and go get something else. An icepick? Talk about using the right tool for the right job...

 

[jstn]

There are knife fiddlers and knife users. Knife users don't have the time to model their knives with $1000 cameras, and equally expensive lenses and filters, to try and make it look like they use their knives. Only knife fiddlers do.

And knife users sometimes inadvertantly whack the spine. Usually when withdrawing the knife out of a confined space they were cutting something in. And their haWell snds bear the scars of said locks failing.

Nothing wrong with being a knife fiddler. Knife users just don't like it when knife fiddlers, who have manicured hands, tell knife users that lock strength is not important. Knife users make a living with their hands, and heavily stitched hands or digits, means a loss in income.

Well said!

 

[chiral.grolim]

In for the sake of in.

I would be pleased if someone else wants to whack knives so I have a better idea what I'm buying. But doing it to your own knife is like testing your own Volvo's crash safety.

More like testing the brakes.

One does not need to test their own knife to destruction (crash), but there are certainly differences in lock-strength such that a non-destructive test for one design is quite damaging to another design. If you slam the brakes, will your car stop quickly and within a short distance? Or will the brakes fail from the experience?

What is the point of a lock on a knife? What is the point of a spring on a slip-joint? To keep the blade open against closing-forces below a certain level. What is that level? Is it not important to KNOW that level before exposing yourself to injury? Or at least establishing a working range - e.g. well, my lock can withstand X level of closing force and that is more than I should ever need, I don't need to know the maximum.