"Spine-Whack Test 101" -- Educate me please.

as dann(and the rest of us lefties) knows, a spydie military is not a leftie knife... I've turned a number of lefties away from the millie after I had my grip close the knife. not even twisting.

I have a linerlock(spydie herbst Ti/440c, factory 2nd sale) that constantly fails the spinewhack test, even though it contacts about 1/3 of the way, when I smack wood. My hand it passes. I treat it like a slipjoint, hasn't closed on me yet.

I carry and use a slipjoint, haven't had it close on me yet.

spyderco tests every knife with a spine whack on a 2x4, and one out of 200 gets broken on the machines.
 
glockman99,

I hope you weren't referring to me.

If you were...

1- They fail with a mild spine-press. That means keeping my hands well away from the lock.

2- They've failed with kitchen-knife grip, with as little pressure as you can possibly apply with that grip. Here, there are NO fingers near the lock cutout. In fact, the only places where the liner is touched is near the backspacer/standoffs, where it should make no difference.

3- With a good number of these, the slippage can be replicated even after the lockbar tension was increased, AND after being sent back to the maker to be tweaked.

4- These weren't ones where the liner protrudes significantly above the scale.

Just because it hasn't happened to you doesn't mean that it doesn't, or it won't happen when you're under stress and have more important things to pay attention to.


-j
 
Originally posted by glockman99
I wonder just how many of these "lock failures" are "operator error", due to squeezing the lock-release without realizing it?
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I think some not-insignificant number of failures are due to this. I avoid knives where it's likely this could happen -- liner locks where the liners rise above the level of the scales, for example.
 
I've got two cents to add to this thread.
When I finish a knife, I always "spine whack" it a few times on a hardwood block. I do this not only to test the lock Which I KNOW is not going to fail, but to "set" the blade and the lock together.
The Titanium spring (or any spring) is softer than the blade and the hammering force tends to slightly form the spring to the exact contour of the blade's lock bevel.
A whack test by the customer, is not , in my mind, an unreasonable thing to do. That customer has every right to expect a knife not to fail even in extreme circumstances. Just be sure not to use marble, granite or steel to whack the blade on, it might mar the blade.
When I first started making liner locks in 1985, tested them with a long pipe on the blade and the handle in a vise to see just how strong the lock was. I was impressed to see the titanium handle and spring deform when enough pressure was applied and the lock still held. Extreme, yes but it gave me a good idea of what lock integrity was all about.
A final note: I've noticed that construction and material of a handle will sometimes cause a lock to fail because of, what I believe, is harmonics set up by sharp blows to the blade. It appears that thin liners are more apt to flex and "bounce" off the lock rather than actually failing as under slowly applied pressure.
I hope this did't confuse the issue. BOB
 
Bob, it's good to see you around these parts :)

I actually test each knife for sudden shock ( spine whack ) and gradual pressure ( blade in vise and closing pressure applied ). I do this to ensure the lock and other parts are built correctly. Any knife that fails is introduced to the 12 ton press, or I get a new EDC. - Charles
 
Originally posted by bobterzuola
I've got two cents to add to this thread.
When I finish a knife, I always "spine whack" it a few times on a hardwood block. I do this not only to test the lock Which I KNOW is not going to fail, but to "set" the blade and the lock together.
The Titanium spring (or any spring) is softer than the blade and the hammering force tends to slightly form the spring to the exact contour of the blade's lock bevel.
A whack test by the customer, is not , in my mind, an unreasonable thing to do. That customer has every right to expect a knife not to fail even in extreme circumstances. Just be sure not to use marble, granite or steel to whack the blade on, it might mar the blade.
When I first started making liner locks in 1985, tested them with a long pipe on the blade and the handle in a vise to see just how strong the lock was. I was impressed to see the titanium handle and spring deform when enough pressure was applied and the lock still held. Extreme, yes but it gave me a good idea of what lock integrity was all about.
A final note: I've noticed that construction and material of a handle will sometimes cause a lock to fail because of, what I believe, is harmonics set up by sharp blows to the blade. It appears that thin liners are more apt to flex and "bounce" off the lock rather than actually failing as under slowly applied pressure.
I hope this did't confuse the issue. BOB
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bob-

thanks for the input.. i'm an absolute fan of your work, and i'd like to think that i'm picky & discriminating as hell. do you have a website, or do you strictly sell your knives through dealers?
 
Holy Crap! Bob Terzuola! You must buy his book-the Tactical Folding Knife! It Educated Me immensely. In it, Bob Explains how the liners and Lock recess work together on the ATCF, Millie and Starmate to be Fail-safe. Ok, back to discussion..Joe
 
This is another one of the Holy Wars of knife users. There are many respectable custom and production makers who spine-whack their own knives before delivering it to the customer (as illustrated above). Then there are just as many makers who consider it horrible abuse and contend that it shouldn't be done by anyone.

If you feel it's a valid test for your knife, I say go for it. If you feel that it's a deadly sin, don't waste your time with it. It seems that once a person chooses their side of the fence on this one, nothing will change their opinion. For that reason alone, these threads usually just end up as pissing matches between users who usually get along.

Even if you don't think the spine whack test is worth anything, perhaps you might consider why certain lock types fail more readily than others. For example, placing a knife in a vise and jumping on it is an activity I would consider abuse, but if such tests consistently showed differences between lock types, I would want to explore the "how" and "why" of such findings.
 
I think a light - to - moderate spine whack is an appropriate test for linerlocks. I don't do it any more, though, because I got rid of all my liner locking knives! ;)
 
Anonymous, you can order knives from Bob by phone or email but I dont believe he has a website. The quickest way to get one from him is to get to a show he's at.
 
It seems like framelocks are a safer way to go. From what I've been reading they are harder to accidentally close.
 
Anonymous:, Sorry, as Lifter said I don't have a website but my knives are on several sites to look at. I do answer the phone and have a fax. My new American Made PRODUCTION knife, due in January, does have an E-Mail address TerzuolaAM@AOL.com. You can see it and others of mine at TrueNorthKnives.com. Thanks for asking. BOB
 
Originally posted by bobterzuola
Anonymous:, Sorry, as Lifter said I don't have a website but my knives are on several sites to look at. I do answer the phone and have a fax. My new American Made PRODUCTION knife, due in January, does have an E-Mail address TerzuolaAM@AOL.com. You can see it and others of mine at TrueNorthKnives.com. Thanks for asking. BOB
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^^look at this stud! that's a certain level of success when you don't have to bother with having your own website & your knives are flying off the shelves regardless, hehe.

i'll contact you soon as my 33rd birthday rolls around & my wife gets the old "hey, there's this really incredible knife i GOTTA have" speech.

:D

thanks for responding, bob.
 
i just checked out the "american made" production folder -- attention readers, this is a handsom carbon fiber scaled, 4" s30v flat-ground recurve tactical folder for $325!!!

bob - please tell me this model is available in lefty. pretty please.
 
Originally posted by anonymous
^^look at this stud! that's a certain level of success when you don't have to bother with having your own website & your knives are flying off the shelves regardless, hehe.
Click to expand...

dude, this is TERZUOLA.

he dont need no steenkin website... :p

-j
 
Sorry , Anonymous ( who are you anyway???) we're not doing lefties this time around as it is the first project in the series and I needed to keep it simple. The thumb disc does allow for eay opening either way.
Have a geat Holiday season to you ALL. BOB
 
Hey Anon:

Bob is a legend. He will make you a nice left handed folder for I think between $400-500. I think his wait list is about a year. You know if you are left handed you have to special order knives. You may not like it but that's just the way it is. And you can always get a Sebenza left hand for between $300-400.:cool: :rolleyes: ;) :p
 
Originally posted by Scott Dog
And you can always get a Sebenza left hand for between $300-400.:cool: :rolleyes: ;) :p
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lmfao! good stuff, but not quite close enough to the "terz" league, even at 50-100 bucks less.. knowhatImean?

bob, my name is alan aragon :D
 
Originally posted by brownie0486
It's abuse to whack the spine on a hard object with much force to my thinking.
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To me it's not abuse, it's a test to determine whether a knife is good enough to meet my standards. So far I've been lucky - I never had a quality folder's lock fail on me, ever after very forceful spinewhack tests.
 
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