Kukuri Failure. Rat tail broke a full tang looks good from now on.

D

Don'tkillbill2.0

Joined
Feb 5, 2012
Messages
78
My Rat Bastard Kukuri!

Have alook at my kukuri and it broke. I guess knives are for cutting and axes are for splitting wood. Lesson learned.

[video=youtube_share;UtjdBNKMnIs]http://youtu.be/UtjdBNKMnIs[/video]
 
I BELIEVE the problem is the tang tapered too fast from the blade. It was too square of a transition causing a huge stress point.
Another problem is your technique. You NEVER try to smash the wood down when it's stuck on your blade.
That's like adding a bunch of weight onto the front of your blade and slamming it down. too much pressure.
I've split plenty of wood with my Himalayan Imports Ang Khola (Plug plug plug) with no problems. Some pieces bigger than the ones you were splitting!
This is all just my opinion though. I might be completely wrong so take it with a grain of salt!
 
The tang should have been plenty big enough to handle what I saw in the video.

Several things come to mind, in descending order.

1. The grain at the break looks very large. All else being equal (alloy, cross section, even Rockwell hardness) the blade with the finer grain will be tougher. That's why a good knifemaker will normalize at least once and perhaps several times before he hardens and tempers, to relieve stress and refine the grain to make it tougher. Take a look at these very convincing photos from an experiment another knifemaker did: http://paleoplanet69529.yuku.com/topic/47099/NormalizationGrain-Size-Control-Experiment-normalize That convinced me, and I now triple normalize every blade I make. Cheap insurance.
2. Everything I have ever seen about khukuris has them being forged from leaf springs. That's typically an excellent steel and there are probably more working knives floating around in the world made from leaf springs than anything else. I made all my blades from salvaged spring steel for a good while. However, it is possible for the steel to develop micro cracks from flexing going over rough roads over the years. These may not show up until the blade is being used at which time they will cause it to fail dramatically. Given the crack on the spine, I think that may have been a factor. As I got more and more folks buying my knives and I began to serve military customers, I made the transition to brand new 5160. Once again, cheap insurance.
3. The cold temperatures may have exacerbated pre-existing problems.
4. It may have been a combination of several or all of these factors, maybe some others.

The sharp corners at the blade/tang transition are another issue, but I don't think they came into play here. Looks like the break happened a good inch or more back from the shoulder. It could be involved, however.

So the problem is not the hidden tang but something else, in my opinion. That looks like more steel than an Estwing ax has in the handle, and how often do those break?
 
Holy cow... Something definitely went wrong with that piece of steel. Even under the worst misuse, properly made 5160 of that thickness should be basically indestructible. They hold up 2 ton trucks with no issue, so you'd have to be superman to snap that thing if it weren't messed up somehow...


Don't let that bad experience hinder your use of the other one. IIRC, we've both got blades from GK&CO. I've chopped up a whole 30' tall, 8" thick tree and split it into firewood with mine, along with some overgrown hedges in my yard that are ridiculously hard wood. Mine's still going strong. Under normal conditions, their blades are tanks.
 
I feel your pain, but you are overgeneralizing about khukuris

Traditionally, the tangs are left soft and should not break.

Not all Khukuri (more like coo coo ri) are created equal. Some are merely KLO - khukuri-like objects.

The hidden tang has been used for centuries in khukuris and battle swords. There is nothing inherently wrong with it. Also, it transmits less shock to your hand.

People who bought Ford products in 2003-2004 had wheel bearings fail in under 30,000 miles. That's not an inherent problem with bearings.

You might get a khukuri from a company with a better reputation. HI happily sells north of the border. http://www.bladeforums.com/forums/forumdisplay.php/739-Himalayan-Imports
 
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Storm Crow said:
The tang should have been plenty big enough to handle what I saw in the video.

Several things come to mind, in descending order.

1. The grain at the break looks very large. All else being equal (alloy, cross section, even Rockwell hardness) the blade with the finer grain will be tougher. That's why a good knifemaker will normalize at least once and perhaps several times before he hardens and tempers, to relieve stress and refine the grain to make it tougher. Take a look at these very convincing photos from an experiment another knifemaker did: http://paleoplanet69529.yuku.com/topic/47099/NormalizationGrain-Size-Control-Experiment-normalize That convinced me, and I now triple normalize every blade I make. Cheap insurance.
2. Everything I have ever seen about khukuris has them being forged from leaf springs. That's typically an excellent steel and there are probably more working knives floating around in the world made from leaf springs than anything else. I made all my blades from salvaged spring steel for a good while. However, it is possible for the steel to develop micro cracks from flexing going over rough roads over the years. These may not show up until the blade is being used at which time they will cause it to fail dramatically. Given the crack on the spine, I think that may have been a factor. As I got more and more folks buying my knives and I began to serve military customers, I made the transition to brand new 5160. Once again, cheap insurance.
3. The cold temperatures may have exacerbated pre-existing problems.
4. It may have been a combination of several or all of these factors, maybe some others.

The sharp corners at the blade/tang transition are another issue, but I don't think they came into play here. Looks like the break happened a good inch or more back from the shoulder. It could be involved, however.

So the problem is not the hidden tang but something else, in my opinion. That looks like more steel than an Estwing ax has in the handle, and how often do those break?
Click to expand...

Sounds like you know what your talking about and since I have a replacement blade that seem a little more refined I will test it out to see how it goes.

A lot of people are telling me to batton the wood. This was a controlled test in my back yard. I love kukuri's but before I rely on and gear I test the crap out of it.
 
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Grease said:
Holy cow... Something definitely went wrong with that piece of steel. Even under the worst misuse, properly made 5160 of that thickness should be basically indestructible. They hold up 2 ton trucks with no issue, so you'd have to be superman to snap that thing if it weren't messed up somehow...


Don't let that bad experience hinder your use of the other one. IIRC, we've both got blades from GK&CO. I've chopped up a whole 30' tall, 8" thick tree and split it into firewood with mine, along with some overgrown hedges in my yard that are ridiculously hard wood. Mine's still going strong. Under normal conditions, their blades are tanks.
Click to expand...

Thank's Grease and let me say this GK&CO did send me a replacement blade. So they didn't leave me hanging.

Maybe the replacement will pass the 100 log test :D DONT FORGET THE BACON!
 
As another said, dont let one bad experience sway you from the khuks. From my humble experience with khuks it seems that a few other companies make a better quality khuk. The tang definitely should not have broken, they can withstand tons of abuse and as I recall you only had this khuk a short amount of time. Have you checked in our sub forums for the Himalayan Imports khuks, they are some pretty serious blades and the customer service is the best I have seen. They have deals of the day and the prices are very reasonable. I own several from them and they are build like tanks. Also check out Tora blades, they have some very nice khuks as well. I hope you continue with the khuks, they are a pretty versatile blade.
 
I will stay with them I was just out side with the replacement knife and giving it a good test. I will likely upgrade next purchase.
 
If you buy another kukri you owe it to yourself to buy a Himalayan Imports. Then, first hand, you will see that not all kukris are created equal. Their customer service is top notch as well.

Tora blades are great too but they are a 3 man shop and getting a kukri from them can take quite a while.
 
Guess there was more wrong with the Khukri than just the Crack. Bummers that it failed. At least, you already have the replacement. Thanks for keeping us posted. I've been waiting to see how things went with that one.
 
Mete thanks for the link but I know how to baton that wasn't the point of testing the knife and unforunately I was dealing with poorly tempered steel :(


the new blade is working good but it needs much more testing to be trusted.
 
Don'tkillbill2.0 said:
Mete thanks for the link but I know how to baton that wasn't the point of testing the knife and unforunately I was dealing with poorly tempered steel :(


the new blade is working good but it needs much more testing to be trusted.
Click to expand...

Testing is good! Please keep us posted.
 
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