Fixing a bent edge

W

WTMC

Joined
Oct 9, 2007
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I've done several searches on the forum and can't seem to find any info on straightening out several fairly severe bends along the edge of a blade. I've got a 20" Sirupati, which is a truly awesome knife, but I think I overestimated its ability to handle more rigorous chopping. I was trying to take out a small dogwood tree in my yard when I realized that the edge of the sirupati had started to bend dramatically. This was after several pretty hard chops. There are three bends in different directions all in a row, creating a wave-like effect. It definitely doesn't look like something I can sharpen out. So, my question is how would I go about repairing something like this? Any help would be greatly appreciated. Thanks. -Will
 
Hmmm. I don't believe the edge should be doing that. Even though the Sirupati is lighter compaired to some of the other "choppers" like the AK it is still a thick stout blade that shold have taken that Dogwood down with ease and no edge damage. Sounds like the blade is to soft.

Who made this khukuri?
 
I had a YCS do that to me five or six years ago (good Lord has it been that long?!). It was defective, sounds like your Sirupati is as well. I've done some light chopping with my 25" Kobra and it held up just fine. A properly hardened edge shouldn't wave like that. It might bend a little in one spot, but it won't give you that ripple effect.
 
I agree that this is an indication that most likely there is a defect in this blade. I have sharpened an 18" WWII khukuri made by Kumar to the level that it can peel a napkin! After it reached that level, I tried it on lamb that was roasted on the spit. All bones were cleanly severed, not even one was broken! After I finished preparing the meat for lunch, I could still peel an apple with the edge!
On the other hand I have a 16" bowie (out of which 10" is the blade) that suffered some serious blade chipping while I used it on spruce. What I did was that I reground the edge for about 6.5" and then I honed it using my Spyderco sharpmaker. It reached the level that I could easily shave hair off my arm. After that, I went back to the field to see how it would perform. This time the knife zipped through wood with amazing ease and what's more important did not suffer any edge damage at all. One may ask what the reason is for it. It has been mentioned in the past by people much more knowledgeable than me, that during heat treatment the blade may suffer decarburization, i.e. lose carbon if overheated. This carbon is lost from the outer part of the blade and if you remove that outer part, you may end up with a very decent knife.
I hope that helps.
 
I discovered the same problem with the 15' BAS I received last week.
I have done some chopping, having gone out to harvest some fallen apple tree branches for knife scales.

I have noticed a wave like effect forming on the edge slightly above where I imagine the sweet spot is. ( I have not etched the khuk to discover where it truly sits.)

The blade is not marked by a Kami, Yangdu sent it to me out of the goodness of her heart when I barely missed a DOTD some weeks back.

Should I be sending this back for replacement considering the excellent price I paid for it? Or should I be sharpening this out and just seeing how it goes?
It has performed as I hoped it would, it chops much better then the 18" M43 I purchased some months back.

Im not sure my photography skills are up to capturing the damage, though I suppose I could certainly try.
 
it would seem that HI has developed some quality control problems. I would recommend that you return it to Yangdu as she would want her father to be aware asap.

If this type of thing keeps happening, bad blades will turn into bad sales. HI needs to know about this as soon as possible and others with similar issues should also be posting their experiences.
 
Yangdu needs to know about this. I'm sure shipping it off right now would be fine, but you might send an email first to let her know that it is coming. with all the comings and goings of mail and packages this time of year, I'm sure that its chances of being lost are greater. Besides, Yangdu is on vacation through the holiday.

Don't worry. Yangdu will get it figured out for you:):thumbup:
 
I agree with Steely_Ganz and canadadan. Send Yangdu an e-mail and wait for her reply and once you receive it, you may opt to either try to sharpen out the problematic area of the blade or, send the knife back altogether.
 
Lets see some pictures.... Of the blade & the dogwood.

I dont think of any long sirupatis as tree fellers myself.

Spiral
 
Waves in the blade could be due to the edge being too thin or the edge being too soft. If your Sirupati is similar to mine (20") the edge is unlikely to be too thin. I chopped with the Sirupati with all my strength with no ill effects. I would agree with the others who suggest the edge is too soft.

The edge will have too be heat treated again. Not an easy process unless you know what you are doing.
 
to echo the post by skagsig40,

we seem to be discussing two posters bent khuks, one HI BAS, one Siru of undisclosed parentage.

Is this siru a HI? if so, contact yangdu, if not, try gently hammering the edge back in line, resharpen & hope for the best. pictures would help us to decide if it is beyond the quick fix...if the bends are in the sweet spot then it's edge is likely too soft & it will happen again.
 
Yes, my siru was from HI.

Just as a follow-up: I contacted Yangdu about the problem and a replacement was kindly offered. I just received it in the mail today and upon the first test chop the blade snapped off completely at the hilt! Sigh...Talk about bad luck.
 
WTMC said:
I just received it in the mail today and upon the first test chop the blade snapped off completely at the hilt! Sigh...Talk about bad luck.
Click to expand...

This is not good news, honest though. It sounds as if there may be a problem with the lighter blades. Can you mail me a photo of the makers marks on the just broken siru?
 
I actually have a similar problem with a blade I recently received from HI. I'll try and get photos tonight and let Yangdu know.

The blade is an 18" chiruwa Ang Khola from the Christmas deals. It had originally been tagged as a Christmas present but once I received it I could not bear to part with it. :)

The leading edge developed a wave the first time I had it out. Looking at it, I strongly suspect it to be a heat treat problem. If it had been ground too thin and treated I would have expected a chip or a crack however it just waved out.
 
I took some photos to try and show it. Wish I had thought to do that before I had started to realign the edge.

First, to give you an idea of the affected area:
img0365nc1.jpg


This is a shot edge-on to show the "wave":
img0372gy7.jpg
 
That's definitely a soft edge, mine did the same thing. No worries, Yangdu will make it right.
 
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