Catastrophic blade failure

Discussion in 'Himalayan Imports' started by ferguson, Oct 6, 2006.

  1. Krull

    Krull

    867
    Aug 18, 2005
    Hmmmm...maybe the old spring they used was not forged right at the beginning? when it was part of a truck? and we're talking bad metal here more then the kami's fault?
     
  2. Ad Astra

    Ad Astra

    Jul 30, 2004
    See Dave's post. Ditto for my experience. Less than 25 whacks on a pine.

    [​IMG]

    [​IMG]

    I think mine's going back, but if so, it's the first HI that ever failed on me or that I returned.

    Thanks, Steve. You get a Purple Heart for taking one for the team.


    Mike :(
     
  3. Dave Rishar

    Dave Rishar

    Oct 25, 2004
    Mine was the second failure that I've personally witnessed. The first was simply a botched heat treat -- not a safety issue, it just wouldn't hold an edge.

    Been a lot of good 'uns and great 'uns before and since. Still a pretty good record in my opinion.
     
  4. Daniel Koster

    Daniel Koster www.kosterknives.com Knifemaker / Craftsman / Service Provider

    Oct 18, 2001
    I only know because of the many knives I have broken. Usually what causes it is an error in heat-treat.

    5160 (leaf spring steel) is a wonderfully forgiving steel...does not need a lot of normalizing, etc. Can even be water-quenched with success (I do it all the time...as do the kamis).

    I think that Steve's experience illustrates best why H.I. has had its replacement policy. Because sometimes stuff just happens.

    I personally have broken almost a half-dozen kukris...some spectacularly, others not. All were replaced (offered, anyway...I didn't take a replacement on one that was a bone-head manuever on my part...as well as one that I purposely tested to failure). Bill used to say 1-in-a-100 will come out whacky (which is pretty dang good if you think about it...99% good)...and that during Daesin/holidays/maoist troubles it drops to 1-in-20 (still 95%). That's good enough for me. If my first kukri had failed...I'd have had a bad impression...but 3 out of perhaps 120-150 that I have owned/tested/used....I'd still say that's good odds.

    What I wouldn't give to be able to go to Nepal and fully document the bladesmithing process. As well as make some measurements, take temperatures, make notes, etc. Only then would I be able to fully understand their process...and where there might be room for improvements. And also learn a thing or two about making kukris. Someday....:(
     
  5. DannyinJapan

    DannyinJapan

    Oct 9, 2003
    I am going to change my vote from a bad temper to a simple lack of knowledge concerning the inner design of this style of khukuri handle.
    I think they built these using an incorrect inner arrangement that is putting too much stress on the joints. Those joints are filled with a natural glue (laha) whereas the original military versions would have been made (i think) with solid cast fittings and/or welded, not brazed.
    It looks like all of the force is being concentrated, levered, in fact, onto the hilt/habaki.
    I think the blades themselves WERE well made, the handle design, however, seems to be well-designed for breaking the tang.
    The hilts should have been solid cast steel or even cast iron so that the tang was supported all the way up.
    If a person is pulling up on the pommel as the blade impacts, that's putting all the force of the blow right on the joint of the tang/blade.
    No wonder it broke.
    These just need solid cast hilts.
     
  6. Big Bob

    Big Bob

    Oct 13, 1999
    I agree, Danny. The MM style of khukuri is one that Kumar is likely unfamilar with. IIRC a few years ago Keser had problems with some of his thinner edged khukuris failing because he wasn't used to making them so thin.

    Bob
     
  7. Krull

    Krull

    867
    Aug 18, 2005
    1-Ad's pics don't look right,what on earth kind of weld IS that? it looks like brass.

    2-Where's the pommel nut? (and I mean nut that screws on)

    3-isn't laha a natural epoxy? that ain't made to hold metal.

    4-yes I'd prefer a one piece molded handel then three seperate parts.

    5-You might think I'm nut's but maybe filling the handel with molten metal (even aluminum) might help.
     
  8. Bladite

    Bladite ǝɹnsıǝן ɟo uɐɯǝןʇuǝb Moderator

    Feb 28, 2003
    eight dollar mountain foundary manages to mold molten metal handles onto their knives. very solid, very comfy, quite excellent.

    my prior thought still holds ... good blade, proper tang, and a handle treatment that probably ran the tang through some temps and it became fairly brittle as a result. oops.

    yah, there shouldn't be ANY laha in a solid metal blade/handle combo imho. it should be solid metal. the handle should be fitted without heat, or cast on without hurting the prior heat-treat, yes? tricky, possibly difficult work.

    all the other museum models should probably be carefully tested.

    bladite
     
  9. kronckew

    kronckew Basic Member Basic Member

    Aug 17, 2003
    short stub tangs held into the handle with pitch, laha, or whatever the local equivalent is have been used for centuries on chopping tools and weapons. it will require more frequent grip replacement than a full tang design but should not normally fail like steve's one did.

    the brazing in the second ad astra picture looks like it did not take (poor surface prep & fluxing?) and the fit of the bolster is less than perfect..not necessarily going to lead to a catastrophic disintegration like steve's, but a failed construct nevertheless.

    the pics from steve show a typical 'frosted' brittle fracture, the 'chevrons' in the grain structure point to the failure point which is the black defect on the right of steve's second picture. this appears to have been a stress crack, probably caused on hardening, which has rusted black inside well before the stress of actual use, and when finally used was a stress raiser that caused the catastrophic failure. the fine grained but very narrow band of grey on the left of the tang was a less brittle fracture and possibly acted as a 'hinge' as it failed, assisting in flipping it backwards into steve. the crack was possibly small enough to be unnoticed. it does look like the tangs could do with a bit more cleanup and finishing prior to grip installation, as well as a bit more QA at the shop, however a crack like that one could exist for years before just the wrong stress causes the failure. happens on ships, unfortuneatley sometimes they sink.
     
  10. Svashtar

    Svashtar Gold Member Gold Member

    Dec 28, 2003
    Steve, I hope you will heal quickly and this will not affect your work. Sounds like a painful injury, and thank goodness you didn't lose a body part, :eek: OR get injured even more seriously! That is a big blade to be flying around. Thanks for doing the right thing and speaking up.

    Out of many, many, purchases, I have sent just two HI blades back, both by the same kami, both because of blade edges that were just totally out of line and unusable. One with the most beautiful antler handle I have ever seen. (Sigh! Forget the blade, I wanted to keep it for the handle LOL!) Both were cheerfully replaced by Yangdu.

    Vim's first or second horribly crooked 13" Crow knife should never have left Nepal, and I probably should have sent it back, but I used it as a practice knife and ground it out and it looks pretty good now, being 3/4" shorter and several ounces lighter with a re-profiled handle as well. I etched it and was disappointed to find only half the blade hardened, but understand that practice has been changed for the "smaller" knives now, so that they are fully hardened along the edge. I have a half dozen of his later knives, including an 18" Crow, and as far as I'm concerned he sets the standard now for consistency and quality. Talk about a comeback!

    I chopped a dozen times with my Museum Model and put it away. I am going to look it over carefully, then put on a heavy welding gauntlet and boots and pound on it some more tomorrow!

    IMO Howard's excellent suggestion has been made before, and is absolutely the way to go. All organizations that really succeed and care about quality test their products. Of course being in SQA that's what I know and do, which admittedly skews my viewpoint, but that doesn't negate the validity of the observation.

    A QC check of the blade alignment, chiruwa tang if applicable, handle and handle ring work, bolster, scabbard, and heavy blade testing should be made of every knife before it is ever UB ebgraved. That initialing should stand for something. It might add 5 minutes to the whole development cycle. HI has not done this because A) they have the best no BS warranty in the business, and B) blade failures are very rare in any case.

    Still, there are other failures in manufacturing that can affect the public perception of quality that should be checked every time IMNSHO. If any knife fails on any point it should be rejected. Most of the occasional and mainly cosmetic problems listed below would subsequently disappear overnight.

    When I pick up an HI or other kukri knife I look at several things:

    I first look at the spine and check to see if it's straight or has waves in it.

    I check to see if the spine is level, that is one side is not higher than the other, and if it supposed to be flat as with a big Crow, Malla or R-1, will use a square to check that.

    I look down on the entire blade from the spine to see that the edge and the spine are in alignment; sometimes both can be dead straight on their own, but the blade edge not to be directly under the spine because it was pushed out during forging. This can cause the handle to turn in your hand when chopping (to the left if the blade turn is to the right, and vice versa.)

    I flip it onto it's back and see if the handle north / south points are lined up with the edge of the blade (one of my pet peeves) and look down the edge to see if it wanders.

    I look on both the top and bottom of the bolster to see if it is neatly formed and brazed, and if it slopes the same on both sides of the blade. On knives like the Uddha and R-1 with round bolster I check to see if it's uniformly round, or is canted one side or the other. I check the sword of shiva to see if it has been partially polished out or not, and is straight.

    On swords like the Bhutan I check the guard to see if it is square on the top and bottom and lined up with the blade. The new Chit Bowie has the same type of guard.

    On the HI katanas or other swords with a large guard I check the back of the guard to see if it has been polished out or is scratched and / or has laha on it.

    If it's a chiruwa / panawal tang I check to see if the tang is polished on top and bottom, flush with the wood/antler/horn, and was also sanded smoothly on the sides before the slabs were attached, so that it is both smooth and even on both sides of the tang. Many of the sides of those style tangs are rough and chewed up, which makes gaps and rough spots and peninsulas of metal when the handle slabs are fitted and then filled with laha to "hide" the gaps, which of course doesn't hide them at all but draws attention to the shortcut, which really looks bad I think. (If the tang is hidden, who cares if it's polished, but if it is to be seen then the extra work needs to happen.)

    On the same type of handle I check to see if the handle pins are flush and polished. If not, they can usually be fixed, but what if it's a scrimmed handle?

    On some few of the horn handles I have found a black putty was used to fill gaps, not laha, which I scrape out and replace with epoxy, as it will eventually usually fall out or shrink. Or, the more common finding is that any gaps are filled with dried red rouge from the buffer.

    I feel for an edge on the buttcap. An edge to the bolster on the handle side, which will only be present if the handle was not correctly cut slightly oversize to the bolster. I check the sharpness with my thumb. I see if the cho is neatly cut and cleaned out of rouge.

    I look at the handle circles near the ring and see if they are cut in a circle, and not in a loose wandering loop around the handle so that they run together and look sloppy, and that they are cut deep enough and not shallowly. I check the ring itself to see if it's uniform. If it's a knife like a Katunje or Chitlangi or Balance or Chainpuri with further handle markings I check to see if they are cut deeply and evenly, or if I will have to redo them. (Often on horn handles they will have been cut and then partially polished out.) I hold the knife and see if the handle ring is too far back or forward.

    I put the knife in the scabbard and check if it is fitted properly, to the blade and not the bolster, so that the knife stays put when inverted as it absolutely should.

    I check the karda / chakma holes to see if they are lined with leather so the little nails don't butcher the new handles.

    I check the scabbard to see if the leather is smooth, the frog is sewn and fitted correctly, the frog hanger was cut evenly, and the chape was fitted properly to the scabbard with no gaps or sharp edges.

    Finally (now, but I didn't always do this) I chop a little with it and slap the sides of the blade against the work to see how it feels in the hand and the blade holds up. For over two years I rarely did this, despite Yvsa and Uncle Bill and others repeated counsel to do so, so now have a great many HI knives that have never been tested at all or minimally. And still I don't do it as vigorously as Uncle Bill urged when I do do it. I really need to do this for all of them, but am afraid of what I'll find out I guess. Statistically I would probably have to replace 2 or maybe 3. But the fact is that every single knife I _have_ hard used has held up beautifully. Sure some dull quicker than others, but no failures or even edges turning.

    Then, depending on the issues, I fix them. Usually there are none, or only minor, or just cosmetic that don't affect performance. Some I can't fix, but considering the value and price of HI stuff and the fact it's all handmade, I don't sweat it.

    The only Kami that has never had any of the above issues for me is Sgt. Khadka. And I understand that he is not part of the main shop. I imagine being on his own he can take his sweet time and work on his own schedule which would help immensely. He does not do that many knives in any case when compared to Bura, Sher and Kumar, etc. (Actually, Khadka almost never applies leather to the karda / chakma holes, but he buries the brads so deep that they usually don't touch the handles.)

    Sorry for the long post. I'll take my MM out tomorrow and pound on a railroad tie with it and see what happens. (Wish I had the supply of natural wood Munk and some of the rest of you have but that will have to do.)

    We'll see what happens. Keeping my fingers crossed there won't be any problems; I love the look and feel of mine.

    Steve, smoke going up for a quick recovery. Glad you're OK bud. And no one who knows you even the slightest would ever think you would call down a no-good $ grubbing lawyer on HI! (Oh! Sorry Berk! / Shann! :D)

    Norm
     
  11. spiraltwista

    spiraltwista

    Nov 29, 2002

    Thankyou Munk. Your comment is very enlighternimg, to me.

    i wasnt refering to other companies. thats your personal axe to grind. Not mine.


    I was pointing out the 1 in 1000 risk of seconhand steel.


    {as was pointed out to you & I on the other forum Nasty is moderater off.}

    I thought my point was constructive. Howards idea of testing would reduce the actual & legal risk.

    Pity you have stepped back so far .

    Spiral
     
  12. sams

    sams

    Apr 21, 2001
    See Dave's post. Ditto for my experience. Less than 25 whacks on a pine.

    ........................................................................................................

    I think the questionable cracks on this khuk is nothing more than the brazing to hold the "hilt" on the handle.

    That type of connection is ok but NOT designed or intended for hard use.

    Blade failure is a separate issue to cracks in brazing.

    You cannot or should not expect a large steel handle with a large steel hilt brazed to hold up to heavy chopping / beating. If you want a chopper, use a AK.

    I know all the HI is supposed to be atom bomb proof but lets use a little common sense on what to expect from the design and assembling of khukuries. I never intend to use my"stag" handle BGR for chopping. I use my 15" AK for heavy use. I know the stag will crack or fall apart. It is not the kamis fault


    Ah lets see, I remember, use the right tool for the right job. A wrench is not a hammer.

    Some khuks are for mostly display, regardless of the HI guarantee.

    Sam S.
     
  13. Nasty

    Nasty Chief Cook & Bottle Wash

    Nov 11, 2003
    munk & Spiral - you've both had your say...done. Don't ask to see me demonstrate my secret super powers.

    Back on topic...test 'em boys...test 'em good, test them carefully.

    Smoke for good recovery continues.
     
  14. tedwca

    tedwca

    Dec 10, 2005
    Nasty - you da bomb! :thumbup:
     
  15. DannyinJapan

    DannyinJapan

    Oct 9, 2003
    i'll take somebody's if they want, maybe i can re-engineer the handle.
    im interested in trying.
    ill trade ya for an 18" pen knife.
     
  16. Krull

    Krull

    867
    Aug 18, 2005
    I know about eight dollar mountain foundary,I have a cutlass I posted pics of from them-talk about bomb proof!

    A handel of three chunks held together by brazing or whatever needs filling (to my mind) with ether good epoxy or some easy-to-melt metal and then a good pommel nut and if you want to be real sure a pin through the handel as well.
     
  17. eswartz

    eswartz

    746
    Jun 29, 2005
    Well, I tested mine out fairly well yesterday.

    I did the bend test, putting it between two tree forks and bouncing it back and forth for 5 min. or so with all my weight.

    I beat the flats against trees til I was tired. I beat the spine on trees until they bruised. :)

    I also chopped stumps and other things.

    I successfully loosened the laha in the bolster/blade junction, but I don't see how that wouldn't loosen on any khuk with this treatment.

    I didn't get any cracks in the handle/ring joints or movement of the blade in regard to the handle.

    In my opinion, the failure Steve had is a completely different problem than the failures Satori or Ad Astra noticed. Steve's was a break in the tang. He didn't mention any problems with the handle. This is a serious failure. Perhaps due to bad heat treat or that black stress point at the bottom of the tang at the bolster.

    The others seem to be problems with stress on the handle and bolster, not tang problems. Again, I am not sure how all the chopping stress would not put pressure on these junctions and cause them to loosen the laha in the bolster or crack the handle ring.

    Would these problems translate into breaking the tang if it wasn't flawed to begin with?

    I'm not saying the others don't have a problem. Mostly I'm just speculating.

    Eric.
     
  18. ferguson

    ferguson

    Feb 21, 2001
    On the way home from the doctor, my wife got serious. You see, there's something about married life, that she takes very much to heart, even after 29 years. So she asked me, not, whether I could still play the violin; not, whether my work would be affected; but what I will delicately term, "my husbandly duties".

    So I'm proud to say....














    I can still vacuum and dust the floors!! Hooray!

    Steve:D
     
  19. spiraltwista

    spiraltwista

    Nov 29, 2002
    :thumbup: :D
     
  20. mndart

    mndart OH! Dog walker Platinum Member

    Apr 16, 2004
    Steve, It is good to know that you can still perform!! LOL!!
     

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