The Khukri - Myth or Fact ?

[fearn]

I'm working on something else, but a while back, on the Himalayan Imports forum, someone published a little computer analysis of a khukuri blade. It was interesting, because it suggested that a lot of stress accumulates on the blade at the cho, and if the cho isn't there, there's a fairly good chance of the blade splitting. Because the cho is there, the blade doesn't accumulate stress on that part of the edge a crack, and therefore, the khukuri can hit with full force. The smiths would have figured this out by seeing blades split where the cho is and experimenting with putting a hole in the blade at that point to stop the crack before it starts.

While I don't think this reason is definite, it's nice in that it doesn't particularly matter what shape the cho is. The fact that there's a break in the edge at the point of maximum stress is the critical thing.

Best,

F

[Berkley]

As with much internet material on my hard drive, the original source for this collection of kaudi photos has been lost. I believe it was originally put together by Artzi Yarom; John Powell posted it on IKRHS. In this version the blade edge is turned up as Spiral suggests to better illustrate the symbolism of the designs.

[spiral]

Excelent Berk, Thanks Fearn if you can find that thread Id be interested to read it.

Although thiese are full of symbolism {Like all Hindu weapons} The kaudi can have less estoteric uses as well.

Pour full fat milk {To emulate blood.}all over the blade & wave the kukri around & you will find less milk gets on your hand if there is a kaudi or step.{Realy... try it. }

It provides a break in the sharpening line so the edge ends at the same spot even if roughly resharpened in the field. {Or village.}

Kukri that break have been overhardend in the riccaso/tang area, fileing the kaudi allows one to know how hard or not the blade is at that point & allows the kami to re adjust temper if neccasary.

I am sure there other practical reasons as well, But putting the power of the Gods into your blade & protecting you from the malevolent spirits Hindus believe are attracted to weapons that have maimed & killed is going to be fairly high on the list, I suspect.

Spiral

[TribalBlades]

Originally Posted by Berkley

As with much internet material on my hard drive, the original source for this collection of kaudi photos has been lost. I believe it was originally put together by Artzi Yarom; John Powell posted it on IKRHS. In this version the blade edge is turned up as Spiral suggests to better illustrate the symbolism of the designs.

Wow superb pictures. dont mind if i use them elsewhere, will ya?

[fearn]

I don't know if you can see this thread without being a member of bladeforums, but here's the blade forums link.

The analysis is also posted here on Google Docs, which requires you to have a Google account.

In reading the Google version, I'll admit that I was wrong, in that the geometry does matter somewhat. A simple semi-circular cutout reduces the stress the most, and sharp angles bring the stress levels back up, where the sharp angles occur.

Hope this helps,

F

[spiral]

Thanks Fearn interesting,,,A fascinating read.

As the auther says though....

"I did not use real values for the geometry. I used generic structural steel material properties and did not account for the variation in modulus from the differential heat treatment or hardening. I did not check for mesh convergence, or verify my results were in accordance with the beam equations. I did not apply realistic loading conditions. In other words, please take these results with a grain of salt!"

As many of those factors are critical in the design & forging of kukris I think his advice to take with a grain of salt is correct.

But Many good points raised especialy re. reduction in transmited shock & vibration I think. I hadnt considered that before. I am sure thats a valuable hypothisis.

Spiral

[fearn]

There's a master's thesis waiting to be written here, really.

A few of things that can be done:

1. Creating a proper model of a khukuri, with the three dimensional shape, bend, and differential hardening of the cutting edge.

2. Playing with the tip angles, blade size, bend angle, thickness, cho shape, etc., to see how these affect the properties of the blade.

There's such a variation in khukuri shapes and sizes that someone really could have a lot of fun. If there are simple conclusions, they could even feed these back to the kamis who make those blades, so that the kamis could play with new blade shapes suggested by the model.

Best,

F

[kronckew]

fearn,

i fixed the missing tacoma narrows video at bladeforums