M43 Too Soft?

jdk1

jdk1

Gold Member
Joined
Apr 21, 2010
Messages
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Well, this is the “I’m incredibly bummed” thread. My custom M-43 I received last fall appears to be too soft. I noticed some waving on the blade last winter after chopping some mesquite. I sanded and stoned a bit and chopped some more. The blade seemed fine at the time. Due to multiple surgeries, I haven’t been able to push it too hard. I went ahead and made a leather sheath and reworked the handle. It was my dream khuk.

Yesterday, I took it over to a friend’s place. We grabbed a big chunk of live oak firewood and I gave it a few chops. Not too heavy, but solid whacks. I pulled the blade up and saw a little wave. I figured I just hadn’t worked through enough of the soft metal (it’s a high polish khuk) to get to the hard stuff, even though my buddy, who knows knives pretty well, told me I likely couldn’t sharpen that wave out. We tried batoning and it worked quite well. My buddy was impressed and liked the khuk a lot. I have another surgery coming up within days, same arm, so I wanted to allay my fears. I filed and sanded a little more on the blade today. I then took it over to a large mesquite stump I had acquired just for khuk testing. I gave it some good whacks and my heart sank. The blade just continued to wave.

I would love for y’all to tell me it just needs more sharpening, but I don’t think that’s the case. I pulled out my Tirtha WWII and Murali CAK to see how they would react to the stump. They both chopped away with zero damage. But they didn’t chop near as well as my beloved M43. I felt every whack with the other two, but the M43 just sliced right into that stump with minimal effort. This khuk is a special order/custom and I absolutely love it. I’ve also put a lot of work into the handle and sheath. I’ve included photos so you guys can either confirm my fear or tell me to get with the sandpaper. I’ll wait to see what you guys think before contacting Auntie. I appreciate the help with this. Take care.

M43DamagedBlade007.jpg


M43DamagedBlade011.jpg


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M43DamagedBlade002.jpg
 
Hi John,

I would say rather than it chipped, it rolled.
You might want to roll it with a hard baton and test it with a file; the feel should be "draggish" from the spine and start to feel slippery as you approach the edge.
If it felt the less draggish but doesn't slide off then the edge isn't hardened as it's supposed to be. Might want to do that along the edge from the tip to cho area.

Don't cut yourself.
 
You can feasably get a wave/roll like that when chopping hardwoods like you're doing.
It could be the heat treat, it could also be your chopping technique or a combination of those factors.
It also could be that you've worked the bevel too thin to chop wood as hard as that, that would be my guess by your pictures.
What i would do is take a hammer and block of wood to it to straighten it out and then sharpen it with a more obtuse bevel on it. When auntie gets back i will bring this to her attention and go from there.
 
It could very well be the edge geometry of this specific M43 also.

My personal experience however was that I never saw any edge rolling on my M43s, or other similarly chunky more convex edge profiles, however, I did experience some rolling with the giant Ganga Ram, which had a very prominent hollow grind to the edge, likely to keep it from being as blunt as an axe. It was effective, and the waving was never very significant, and limited to a very short height of the edge. To be honest, your first pic looks like your M43 may have a somewhat hollow edge grind also, which could be the cause of the problem. If the temper were too soft, you'd be more likely to see the very edge folding over when chopping into those hard woods. Come to think of it, I also experienced the same thing with my newer YCS(tirtha?), which decidedly does have a very thin tall edge, more flat/saber ground than convex.


You might just try a heavy sharpening session with a mouse pad/phone book, take a bit more off the edge with slightly higher angle than current, however, if it's reasonably flat or hollow, following the same basic angle should cut down the edge.
 
jdk1, Bummers on the wavy edge. That has to be the pits.

I have some practice straightening edges on Khukris. If you want to send it my way, I'd be more the happy to try to straighten it out and test it for you. I've had bad dreams at night where my favorite Khukri's did the same things or worse, the whole knife warped. :eek: Saw your pictures and immediately wanted to check my khukri's to make sure that my dreams hadn't come true.
 
hammer and sickle approach...

get a 2x4, and a hammer. peen the edge to flat. sharpen. use.

if it does it again, hammer flat, ... work hardening might fix things nicely.

otherwise, sharpen past it... if it STILL does it, it is more than likely a hardening issue.
 
Too thin edge. Edge like my Tamang. No I think even thinner. I'd either file the edge (width reduce by 1/8 or 1/4 inch) and make a new thicker edge or I'll speak with Auntie Yangdu :)
 
John,

Too thin edge. Edge like my Tamang. No I think even thinner. I'd either file the edge (width reduce by 1/8 or 1/4 inch) and make a new thicker edge or I'll speak with Auntie Yangdu
Click to expand...

Did you sharpen it to convex or flat grind?
You might want to look straight into the blade and see if it's indeed too thin of an edge.
 
From pic #2 it shows waves going in both directions and a good bit into the meat of the blade, not just the edge. Usually this waviness points to an overall hardness issue and isn't something that sharpens out [in any knife.] I would send it back and ask for another with a villager finish and the same specs so it fits in your sheath.

Sorry John, I know that one was special.
 
Thanks to everyone who has replied. The edge is more or less how I received it, as far as profile. I really haven't removed that much steel. I'm not very good at sharpening using any method other than my Gatco-like Lansky set up. My WWII flattened a bit when chopping palm frawns/fronds, whatever they're called. I reprofiled the edge on the above mentioned Lansky and it works very well now. If the M43 edge would have folded/flattened or waved at a much lesser degree, I wouldn't have bothered to post. I would've just worked on it when I could. I was just puzzled at how this edge didn't flatten or roll, but waved pretty seriously. I have't measured it, but it seems the wave might extend 1/8" +/- into the blade. Too thin a profile sounds like a possibility and I'm willing to do whatever I can to keep this baby. This is the first M43 I saw from Tirtha and it could be he just worked it a little too thin. I haven't heard of this happening with any of his other M43s, which makes me think this is a fluke deal.

I will be going under the knife tomorrow and will not be able to do much of anything with it for a while. I would love to fix it and discover it just needed some tweaking, as it really is an incredible khuk. Tirtha did an awesome job with this thing. I can't emphasize how pleased I am overall with it. The balance and feel is just perfect for such a big knife (almost 19" and 32 oz.). I'm pretty sure I couldn't get another one close enough to spec to fit my sheath and the handle is custom fit to my paw, done in a sudden burst of ability which really surprized me:). I may very well take Brother Heber up on his very kind and generous offer. If it works, I'll be a very happy man. If it doesn't, I'll get with Auntie and see what she thinks. Wildman, I'll likely email you soon. Thanks again to everyone for the assistance:thumbup:. You have given me a glimmer of hope and I've got nothing to loose by trying. This khuk is just too awesome to not try everything I can. Take care and God bless.
 
People keep mentioning that problems could be coming from when someone is applying the Stone Mirror finish to Khukris. Well if the blades are getting over heated by polishing, shouldn't there be discoloration in the areas that are affected? When ever I'm grinding on steel and get it to hot it always changes colors. Normally it's a bolt that I'm shortening or some chunk of steel for a fence or what not, but there is always a change in color. But the blades that I've seen in the past with soft steel don't have this. It leads me to think that the heat treat was poor before the stone mirror finish was applied.

Then again maybe the heat treat started good, it was recked by polishing to fast and then who ever was polishing it removed the discoloration that happened. Would be interesting to know.

Makes me wonder if only the really experienced Kami's and assistants should be allowed to do the fancy Stone Mirror finish and the other less experienced should stick to the rough "villager" style finishes... Just throwing out ideas.
 
I had a knife in which I had a maker put a convex edge on for me. It was ground a bit to thin and did the same thing your edge did, I sent it back to him and he sharpened out the wavy spots. It has been fine ever since. Although the waviness in my blade wasn't nearly that bad... How is the edge retention? Does it take a sharp edge and hold it? If so that would indicate once again, too thin of an edge and not a heat treat issue.

Reading about all of these edge issues is disheartening.
 
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I feel your pain JDK. One gets attached to these blades especially after custom work on it and it digs deep (no pun intended) when something goes wrong with 'em. I hope you can get past the wave on this one.
 
GregS said:
I had a knife in which I had a maker put a convex edge on for me. It was ground a bit to thin and did the same thing your edge did, I sent it back to him and he sharpened out the wavy spots. It has been fine ever since. Although the waviness in my blade wasn't nearly that bad... How is the edge retention? Does it take a sharp edge and hold it? If so that would indicate once again, too thin of an edge and not a heat treat issue.

Reading about all of these edge issues is disheartening.
Click to expand...

From talking with jdk1 via email it sounds as thought his blade is keeping it's edge, just warping. So we are hopefull that it's just ground to thin for his uses. He's sending it to me so that I can carefully convex the edge then test on some old dry Oak. Betting we can get this solved with out having to bother Aunti Yandu with it. :)
 
wildmanh said:
From talking with jdk1 via email it sounds as thought his blade is keeping it's edge, just warping. So we are hopefull that it's just ground to thin for his uses. He's sending it to me so that I can carefully convex the edge then test on some old dry Oak. Betting we can get this solved with out having to bother Aunti Yandu with it. :)
Click to expand...

I think thickening up the edge will fix it as well.
 
Heber came to my khuk's rescue. He has done much for this forum, and me! This khuk deserves every opportunity I can offer it. It should be headed his way next week. I have high hopes for it to be my best khuk with a little tweaking!:) Thanks again for everyone's responses. Heber is planning to do some solid testing while he has it and hopefully he'll post up a good review. Thanks all and take care.

BTW, the surgery went well this morning. I'm just waiting to get some feeling back in my hand:)

Here's a shot of my baby because pics are good!

M-43SheathandbigHIkhuks010.jpg
 
To answer your question about the heat discoloration that would be evidence of de-tempering during the polishing phase wildmanh; You're correct that the coloring would show up, but this light oxidation is very superficial on steel. Unlike titanium, it takes very little to remove it, and subsequently, would be polished away in the next pass most likely.


Honestly, I wish we could get those colors to stick, because it would allow for a lot of aesthetic options when HTing blades.
 
jdk1 said:
BTW, the surgery went well this morning. I'm just waiting to get some feeling back in my hand:)

Here's a shot of my baby because pics are good!

M-43SheathandbigHIkhuks010.jpg
Click to expand...

John, I'm glad that your surgery went well. That is one Lovely M43 you have. That sheath looks pretty descent too. I'll do my best to breath new life into your blade. :)

javand said:
To answer your question about the heat discoloration that would be evidence of de-tempering during the polishing phase wildmanh; You're correct that the coloring would show up, but this light oxidation is very superficial on steel. Unlike titanium, it takes very little to remove it, and subsequently, would be polished away in the next pass most likely.

Honestly, I wish we could get those colors to stick, because it would allow for a lot of aesthetic options when HTing blades.
Click to expand...

Javand, thanks for confirming my suspitions. Sounds like you are talking about Case Colored like whats done to some firearms.
 
My Sher "The Tiger" M-43 suffers from the exact opposite problem. Once the edge is rolled, it takes forever to regain a sharp edge. A local gun/knife guy worked on my blade for over 1hour on his small belt sharpener but was unable to get the edge back. Too small of a set-up, I'm sure, but the big M-43 was too much for him. I've been going at it with a 2-sided stone and am getting results, but very slowly...
 
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