Rolled edge on new khuk

T

tychoseven

Joined
Aug 9, 2005
Messages
317
I got my 16.5 WWII the other day, and I was quite impressed with the knife and its accessories. I took it out a few times and used it to work on some camp projects in the yard, and I noticed that the edge dulled rather quickly, after only a few 2" eucalyptus branches. I gave it some swipes with the chakmak and moved on to some old 1X6 boards to practice my technique. After a few chops I hit a bolt embedded in the board, and the edge rolled. In the picture you can see the bolt and the damage it caused. The edge impacted on the head of the bolt, and you can see the dent in it if you look closely.



(Sorry about the picture quality. You can click on it to see a bigger one.)

I know I'm not supposed to chop metal, but it seems to me that the khuk should stand up to more abuse than this. I mean, there were pics up of the Foxy Folly cutting through a car without rolling the edge. Is it possible the knife wasn't tempered properly? I know HI will make good, so it's just a question of this knife's condition. I like the khuk, but if it's not tempered well I can't fix that on my own. If this is just an issue of me being more careful with what I chop, I can handle that and I'll break out the belt sander and files.

Thanks,
Tycho
 
Break out the belt sander...auto sheet metal is far different than a bolt.

On top of that, khukuris often need several sharpenings to "get to the good stuff" as our resident madman of chopping Satori has noted.

I don't think the khukuri is out of spec...rolling the polished edge happens and you just sharpen it and it usually never happens again. The bolt is an act of...well...it's not made for that.

Try taking a cold chisel and hammer to the bolt to see what happens...

.
 
There are many different types of bolts in this world. They are hardened differently, and have compositions suited for different tasks. I don't think cutting through a bolt is a reasonable standard for a knife. Some khuks might have been able to cut through that bolt without damage, I don't know. But I would never expect one to. I think you should be thinking about what didn't happen when you abused the blade- it did not fail, break in half, or crack. That's a good khuk.


munk
 
Three things come to mind.

First: the hardened area on some khukuris doesn't extend that far down. Some are only hardened on the first 4-5" back from the tip, since that is where you are supposed to be doing the most chopping.

Edit to clarify: Sometimes the tip is hardened, sometimes it isn't. These blades are all so unique that you can't generalize. That's part of the fun.

To determine where the hardened area is, you can try an etch. A lot of posts have been made on the subject of etching. Try searching for "ferric chloride etch" or "rust remover etch". You'll find out more than you want to know.

Second: On forged blades, decarburization can sometimes be an issue. This is where the carbon content on the surface of the blade is lowered due to heating to high temperatures during forging. This leads to a skin of unhardened steel. I think that the first possiblility is more likely to explain why the edge rolled, but this may explain why the khuk dulled quickly.

Now, you can fix this problem simply by sharpening the khuk enough times to remove the skin of decarburized metal.

Third: Proper technique in cutting is very important. I've "accidentally" cut through nails in a board without edge damage, but only when the swing was true. If you don't come in at the proper angle, you will surely dent the blade, no matter how well it is heat treated.

However, cutting through something thick like a bolt (and especially if you come down on the bolt head) is tricky if not impossible no matter how good you may be. Car doors aren't a problem since sheet metal is thin. Likewise with nails and screws. (edit: and as others have said, the kind of bolt matters - I don't think ANY knife out there can cut through a grade-eight hardened bolt.)

I'm sure others can chime in on proper technique for cutting. I'm far from an expert on the matter.
 
I got my chainsaw stuck in a log. I chopped it out with one of my Ganga Rams. From hitting the chain with the khuk multiple times the edge of the khuk looked like yours times ten.

I took it back to the house, put it on a strop with some 200 grit sandpaper, worked my way up to 600 grit and it was as good as it was before.

If you bend your khuk edge bad on hard wood I'd worry. Bending it like that striking metal is normal in my experience. Khuks are for chopping wood.
 
Alright, I'll get to work fixing up the edge. The bolt was sitting in the board at an angle, so although I was cutting straight through the wood, the blade didn't meet the bolt straight on. Unfortunate circumstances. I wondered about temper because I wasn't swinging that hard. I hate to think what would have happened if I had put a full-bore swing into that bolt.

On the positive side, this gives me a good excuse to convex the blade.

-Tycho-
 
think steel car panels are less hard than old rusty bolts.
& that's maybe on the edge of the hardened zone--
depends on the individual khuk.
Etch it to clearly see the harness zones.

Search the HI forum for:
vinegar etch
or
ferric etch
or
acid etch

here's a couple of threads to get you started:

http://www.bladeforums.com/forums/showthread.php?t=322195

http://www.bladeforums.com/forums/showthread.php?t=310924


Knew Khuk Khonnoisseur's Kwick Khoncise Khompendium:
http://www.bladeforums.com/forums/showpost.php?p=3195617&postcount=110


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<> Tips <> Baha'i Prayers Links --A--T--H--D
 
That's just an old carriage bolt, nothing too hard about it. I do agree that it looks like it's right near the back end of the sweet spot and very apt to dent there.
Also agree that all the carburization may not have been removed. Khuk Monster said it well.:cool:

I cut a similar carriage bolt in two with the AK Bowie I once had. It was in a vice with the handle turned fairly slow to cut down on any damage the knife may have incurred.
It rolled as well. A few minutes with the chakmak and it was better than it previously was and shaved hair readily all along its edge without pulling.:thumbup: :D
 
Dings like that are nothing. If there are raised edges around it smooth them down with a stone or a file and go on about your business. Over repeated sharpenings it will disappear on its own.

That bolt is considerably thicker than the sheet steel that I was cutting. :) Also note that when I was cutting up that car, I was expecting far more damage than what I actually wound up with...one of the reasons that I was so pleased. I was anticipating a number of dings very similar to your own.

After a preliminary inspection one of the first things that I do with a new khuk is to sharpen it to my liking. One reason is that I prefer a more polished (and sometimes thinner) edge than what arrives from Nepal, but another reason is that I want to make sure that there's no decarburized steel on the edge to give me a false negative. Sometimes it takes two or even three sharpenings before I really see what the khuk can do. I believe that regular chakmak use (besides being conveniant in the field) also improves the edge considerably.

Short answer? It's not bad now and it will probably improve with time.
 
After a little work with the files, I did indeed get down to the "good stuff." I took off about a millimeter of steel, and the hardness improved considerably. I also discovered that the ding was right on the edge of the primary cutting area, which would explain why it folded so readily. Now I'm gonna go work with my sandpaper and put a nice sharp convex edge on this thing :D

Thanks for the help everybody!

-Tycho-
 
Satori beat me to it! What he said is on the money....just a light touch up, and then rrrock on! Cosmetics don't cut wood, any more than a carpenter needs a suit and tie to do the job. Hack away, and smile....
 
Satori said:
Sometimes it takes two or even three sharpenings before I really see what the khuk can do..
Click to expand...

Very true. I think everybody has kind of their own type work they do with their khuks and the khuk works best when it has the edge that is suited to that kind of work. Also differences in strength, and chopping style play into it too. :thumbup:
 
Tycho?

Great inquiry. Great appreciation of the khuk.

You ARE a khukuri man; they were made to be used, worked hard, and fixed to be used again.

My true love of them came with the appreciation that it was not a "pretty," sharp, imported toy, but a real instrument to do various jobs and be repaired on-site if something bent, chipped, or dulled. Axe, knife, weapon...utility tool.

Welcome to the club.
 
"Safe Queens" don't go to the dance!

Beat it up some more. Post pix.

20 years of dinging & resharpening and you've got a Malla, an even better lookin' khukuri.


Ad Astra
 
06-29-2003, 09:58 AM
Bill Martino
Registered User Join Date: Mar 1999
Location: Reno, NV, 89509
Posts: 34,096

Which goes to show you that you can abuse a knife and still bring it right back to life. It does look like new and good work. Just because you ding and beat up your knife does not mean it is finished
Click to expand...
 
tychoseven said:
After a little work with the files, I did indeed get down to the "good stuff." I took off about a millimeter of steel, and the hardness improved considerably. I also discovered that the ding was right on the edge of the primary cutting area, which would explain why it folded so readily. Now I'm gonna go work with my sandpaper and put a nice sharp convex edge on this thing :D

Thanks for the help everybody!

-Tycho-
Click to expand...

And you can sit back and enjoy the great satisfaction of repairing it yourself!

Noah
 
That's right. Some blades need more attention than others, or call for modification. Rusty used to call it making the blade yours. I pinned the handle of a an ugly 20" AK villager and it's mine now.




munk
 
Buy an axe or a sawzall if you want to cut through bolts. Knives arent light sabers. An edge less and 2 mm wide, no matter what its composition, is not going to cut through anything of even sclose hardness without damage. The movies with swords cutting rifle barrels are excited because they are outside reality. I still dont understand why some people take a bat to a football game.
 
I think he got his answer, Tictock. I don't believe he was trying to smash his way through a bolt. I've read his other posts and he has done his homework, He just hasn't gotten his swing down yet. He just hit it with the wrong part of the khuk while trying to chop wood. Had he been 1 or 2" up he would had probably dulled the blade and smooshed a bit of metal out to the side. 5 min. easy fix. A lesson was learned. Tycho is on his way to understanding the ways of the khuk. Hell, metal in wood is damn near unavoidable and it always likes to hide.
Tycho, that's a great looking blade you have there. Uncle Bill said scars like that are there to serve as reminders the lessons that we've learned. Use it as is. That blade'll probably outlast you 5 fold.

Jake
 
The only thing I wonder about is: why doesn't the sweet spot extend further down the blade (toward the handle)? If the knife were made harder would it be more prone to shatter? I assume the softer steel lets the blade flex more with the shock of impact.
 
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