Lockback failure

Yekim; don't worry. You are a valued contributer, adding a lot of energy to the forum. We all have our hits and misses (my last miss was last week, and my friend was kind enough to notify me by e-mail; I am still wondering whether to admit to error publically, but the thread has wandered).

So, keep the posts coming. Fire away, and let us old geezers try and keep a lid on your enthusiasm (fat chance, recalling my younger days). See ya soon, Walt
 
Yekim,

No sweat, I wasn't sure myself If you were addressing me, but had to let you know my intentions were sincere, just incase. I actually do like hearing details about how something can be broken and what the causing factors were. It's just that I always accepted the fact that anything that folds 'out' can fold 'in'(when persuaded just right
wink.gif
), so I 'personally' don't trust "any" folder to withstand much more than half a dozen hard whacks on the spine.

I would have E-mailed both you and Walt Welch(thank you Walt), but I'm having errors sending out, however, I'm recieving mail OK.
It's been said that communicating over this medium has a higher probability of 'mis'communications, so It's bound to happen now and again. Keep up the tests!

Ken
 
While I have yet to have any knife fail on me, I too have discarded or refrained from buying certain knives due to information I have found on this forum.
I appreciate all the time and work put into researching this topic as well as the wealth of info shared to all.

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Norwegian Misfit

"For the word of GOD is quick and powerful, and sharper than any twoedged sword...." Hebrews 4:12

 
A poorly made or marginally made lockback will fail under the right conditions. There are couple of things that will contribute to failure.
1.Closing up from the open: fit of rocker and blade. Typically a close tolerance situation. Not only do the mating widths of the slot and head have to be ok, but the angles on the slot and head also have to have a robust match. Also over tumbling of the finished parts or too aggreessive burr removal can cause a rounding of the slot or head. This rounded corner will cause less of the slot and head engagement leading to a situation where even though domensionally you are in compliance, the force to break the lock is dramaticaly reduced. It only takes a little reduction in engagement to allow for a large change in required failure force. Most failures I've seen come from engagement problems when closing not rocker pin movement.

2. Folding open farther than designed: Failure of Rocker Rivet will allow the head of the rocker to move back allowing disengagement. Most times, this directional force creates more blade/rocker engagement (more of the rocker face pushing on the blade. so that forces are transitioned to the rocker pin.

A couple of things to keep in mind:
Most all lockbacks will fail if ENOUGH force is applied.
Once a blade overrides the rocker head, more often than not the back face of the rocker face has been rounded. The integrity of the lock has been comprimised at this piont and additional failures are imminant. This knife should be retired from active duty or returned for replacement depending on the MFG warrenty. This is the same theory applied to a motorcycle helmet after is has been in a crash. Just because there is no outward evidence of failure does not mean the unit is still safe.




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Jeff "Without data it's just another opinion" Hubbard
 
Jeff,

You are quite correct. I was going to post a similar post, but I lack the eloquence and ability to compose my ideas that you have so expertly demonstrated.

I decided to keep the knife because this allows me the chance to perform surgery on cutlery (ironic isn't it, usually it is the other way around
smile.gif
). I enjoy adding my touches to an item, I guess since I am not too artistic, this is my way of expressing myself. I am in the process of modifying the unfortunate Goddard, having already replaced the rocker rivet with a more substansial pin. My next trick is to replace the blade pivot rivet with a pivot screw from my retired SOG auto clip. This will require some drilling, but I am sure that the finished product will be more durable than the original. With the Goddard apart, I am able to fit the tang into the blade notch, and with some careful sanding and fitting, I should be able to make the lock be somewhat reliable, though probably not as reliable as it was originally due to some damage incurred from its failure.

YeK


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"No, it's a Vaquero Grande in my pocket, but I am happy to see you!"
yekimak@hotmail.com
MegaFolderians Unite!!
Dremel Junkies Unite!
Dyslexics Untie!




 
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