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Spyderco Southard blade failure with pics

Discussion in 'Spyderco' started by Atakdog, Jan 9, 2014.

  1. idaho

    idaho

    948
    May 5, 2005
    That shouldn't matter.
    The front part of tang transfer the load to the pin. The back side should not be working.
    It failed, it happens sometimes to everything.

    But I must agree that the cut-outs are quite "radical" :)
     
  2. stog75

    stog75

    194
    Feb 24, 2003
    While I'm not a metallurgist, I did study a little failure of materials in engineering school. What i don't see is from the picture are areas of striation(slow crack growth), fatigue, corrosion, creep or any other slow(er) modes of failure. Looks like a 'catastrophic' shear fracture to me. Perhaps a defect in the manufacture, or worse, design (yikes). Would be very interesting to see Spyderco's explanation of the failure. Lucky the blade was in a block of wood and not 'free' as it would be if you were cutting a loop of rope. You have my interest...please keep us posted with how Spyderco responds.
     
  3. grownstar

    grownstar

    Apr 24, 2013
    That's nuts. I've always been a little iffy when it comes to the longevity of knives with internal stop pins, but I know the team at Spyderco knows how to produce a fine knife. Sorry it busted, but I'm positive they'll take care of it for you.
     
  4. Joshua J.

    Joshua J.

    Feb 27, 2005
    Another reason to be a huge fan of thumbstud stop pins.

    Speaking of which, I just finished taking pictures of my new Vallotton.
     
  5. o4tg

    o4tg

    711
    Jun 12, 2013
    I actually prefer frame captivated external stop pins. I love my 0350, but more than once when I've been using it hard the thought of them coming unthreaded or snapping has crossed my mind.
     
  6. grownstar

    grownstar

    Apr 24, 2013
    Oh I've seen your 0350. If those studs haven't screwed up by now, they ain't gonna! :D
     
  7. o4tg

    o4tg

    711
    Jun 12, 2013
    It's going in for a new blade next week, so hopefully that includes new studs as they're a bit polished now.

    So OP, don't worry too much. With a good company behind the work you'll get taken care of.
     
  8. Mike157

    Mike157 Gold Member Gold Member

    Aug 29, 2006
    From my limited knowledge of failure analysis, the gray, more granular part of the failed part, as mentioned above, is where the catastrophic or instant failure occurred. The shiny part, if it exists, is often a longer lived crack and or defect where the two sides of the crack/material have been rubbing together and have become "polished". In a load/unload condition, sometimes these "cracks" will make a creaking noise. Just me blabbing. It doesn't sound like this is relevant to this situation.
    Despite my engineering background, telling me that something doesn't need to be as massive as I'd like to be "strong enough", I still gravitate toward the more massive. I'm sure, the Southard has been well designed and thoroughly tested and this has more to do with a defect of some type. Mike
     
    Last edited: Jan 10, 2014
  9. stog75

    stog75

    194
    Feb 24, 2003
    Atakdog- you took a nice picture of the break on the blade side. For shts and giggles, could you take and post pictures of the break on the tang side? There are two failure locations, tang side and blade side. I'm tending to believe the tang side may have been the first to fail (maybe happening a while ago, unbeknownst to you.)

    What I'm having trouble figuring out is how the blade side failed without deforming the pivot radius cutout and without disfiguring or blowing the tang side tail piece completely out.

    I apologize for geeking out, but I'm fascinated on how this thing busted!
     
  10. shunsui

    shunsui Gold Member Gold Member

    Aug 12, 2008
    Thanks for posting this and all the great photos.

    Somehow I've managed to miss all this inside stop pin stuff up to now.

    Good to know.
     
  11. ShepardCC

    ShepardCC

    Dec 4, 2012
    That sucks to see happen. Send it in and they will take care of it.

    The directional force and therefore pressure of the blade while in use is on the frame lock and the thick part of the blade where the stop pin is. The thin part of the blade is mostly as a guide and the other thin part where the stop pin connects is really not a big deal. That's just to keep it closed at a certain depth inside the handle. Maybe what happened is while it was closed, a strong enough force was applied to crack the blade and later on in use the rest/complete failure occurred.
    I love my southards and I'm not against internal stop pins at all. It's all about the engineering.

    Also it's a folding blade. If you want something for hard use and safety for the thought stuff, fixed blade. Different tools for different jobs. Phillips and flats heads are both screwdrivers. A flat head will work in both types of screws but a Phillips will only work in one.

    Some of the best Spyderco come out of Taichung Taiwan.
     
  12. crom

    crom Gold Member Gold Member

    Mar 29, 2007
    One had better make really straight cuts with a design like that. The lateral forces probably got it during carving, pass.
     
  13. d0nut

    d0nut

    991
    Dec 5, 2012
    Wow, sorry about your luck OP.

    I'll be following along to see how this shakes out.
     
  14. nccole

    nccole

    Jun 2, 2011
    For anyone thinking it may be a fake go here, http://www.bladeforums.com/forums/showthread.php/796442-Spyderco-Fakes-amp-Knock-Offs-Info/page14

    I don't think it is a fake. Also, someone asked why an internal stop pin. A big reason I believe Spyderco did it was to make the flipper incorporation easier. It looks better in most people's opinions as well. That is not to say all flippers have to have an internal stop pin because we know there are plenty that aren't, but I recall that being a reason. Another factor is simply that Brad Southard designed this knife. I personally would not shy away from the design, but attribute it to a flaw in the steel.
     
  15. skyhorse

    skyhorse Gold Member Gold Member

    Jan 30, 2010
    Looks like something went wrong during the manufacturing process of that particular blade and caused a fracture failure. It happens sometimes even in critical aircraft hardware. I'm sure it's not a design flaw and Spyderco will replace it.
     
  16. A-Ro

    A-Ro

    63
    Dec 19, 2013
    I think you're lucky that when the blade broke off, it didn't fly off and injure you.
     
  17. Poez

    Poez

    Jul 5, 2010
    If you compare that photos of Domino blade to the Southard blade below...

    .... you may notice an important difference: Southard blade is further weakened around internal stop pin area because unlike Domino it has no choil and the grind line comes very close to the pin cut-out.
    I still recognize that the actual cause of the disaster was likely an issue with the blade heat treat, but as somebody who does not trust ISP design, I would be concerned about how it's implemented in this particular case.
     
  18. skyhorse

    skyhorse Gold Member Gold Member

    Jan 30, 2010
    Could be wrong,but I believe it the thick side of the cut out grove that holds when in the locked position?
     
  19. Poez

    Poez

    Jul 5, 2010
    You are right. And I was talking about it: it would be thicker if the blade had a choil, like Domino blade has.
     
  20. skyhorse

    skyhorse Gold Member Gold Member

    Jan 30, 2010
    My BIL is a metallurgist engineer for the DOD and we often discuss failure in machined metals. If something happens to a military aircraft part he determines what caused it to break.When contractors submit bids for metal parts/hardware he also has to determine if the product is up to specs for it's intended purpose. Even with all these inspections,failures occasionally occur.
     

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