# How to fix a warped Deba



## Gjackson98 (Sep 12, 2018)

So I have seen threads about how to fix warping blades. Most people fix it by hand bending. 
Now I got a thick Deba, is this still bendable by hands? 
Or would you guys recommend some other methods?
Please let me know
Thank you!


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## RDalman (Sep 13, 2018)

Sorry forgot your pm was traveling. First, check if it really needs fixing, by laying the ura side on a fine stone. If it's "right" there you should leave it imo. 

For bending that you probably need three rods in a vice method or a bending stick. If those don't work hammer might be the route. But that's very dangerous territory if you're not experienced with it.


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## Kingkor (Sep 13, 2018)

Interested to see where this conversation goes, probably a stupid question but did you try bending it by hand? And did you get it this way?
If you don't find a solution on the forum maybe contact Jon or the smiths here that work with single bevels might need more work than what it's worth.


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## Gjackson98 (Sep 13, 2018)

RDalman said:


> Sorry forgot your pm was traveling. First, check if it really needs fixing, by laying the ura side on a fine stone. If it's "right" there you should leave it imo.
> 
> For bending that you probably need three rods in a vice method or a bending stick. If those don't work hammer might be the route. But that's very dangerous territory if you're not experienced with it.


Thank you Dalman! I will check it out sometime this weekend and give the rods a try. If that doesn't work I don't think I am comfortable enough to hit it with hammers lol.


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## Gjackson98 (Sep 13, 2018)

Kingkor said:


> Interested to see where this conversation goes, probably a stupid question but did you try bending it by hand? And did you get it this way?
> If you don't find a solution on the forum maybe contact Jon or the smiths here that work with single bevels might need more work than what it's worth.


Hahaha no, Its too thick bend it by hand. 
I wonder what kind of process does Japanese maker use, I am assuming they get alot of warp single bevels over time.


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## Kingkor (Sep 13, 2018)

Gjackson98 said:


> Hahaha no, Its too thick bend it by hand.
> I wonder what kind of process does Japanese maker use, I am assuming they get alot of warp single bevels over time.


Throw in seconds pile and make another [emoji23]


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## Gjackson98 (Sep 13, 2018)

Kingkor said:


> Throw in seconds pile and make another [emoji23]


Lol, in that case, some of my knives is probably from pile hopeless.


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## JBroida (Sep 13, 2018)

usually a hammer or chisel hammer is used... but it can take a lot of practice to do well, can easily break the knife, and will often require refinishing


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## Gjackson98 (Sep 13, 2018)

JBroida said:


> usually a hammer or chisel hammer is used... but it can take a lot of practice to do well, can easily break the knife, and will often require refinishing



Thank you! If a Deba is not 100% straight, can it still function ok?


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## JBroida (Sep 13, 2018)

Gjackson98 said:


> Thank you! If a Deba is not 100% straight, can it still function ok?



To a degree, but every time you sharpen it will get a bit more messed up


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## RDalman (Sep 13, 2018)

Fun sidenote fact. Single bevel knives always bends in the quench. The steel grows so the iron will pull it quite alot. I think it's common in japan to "prebend" the knives before quench to make them come out as close to straight as possible. But straightening is always part of the process, when grinding as well as they will move around easily..


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## JBroida (Sep 13, 2018)

RDalman said:


> Fun sidenote fact. Single bevel knives always bends in the quench. The steel grows so the iron will pull it quite alot. I think it's common in japan to "prebend" the knives before quench to make them come out as close to straight as possible. But straightening is always part of the process, when grinding as well as they will move around easily..



I haven’t seen a lot of pre-bending except in honyaki knives


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## RDalman (Sep 13, 2018)

JBroida said:


> I haven’t seen a lot of pre-bending except in honyaki knives


Found a sample. Look at 7,30


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## Gjackson98 (Sep 13, 2018)

this is probably the most completed process I have seen so far, eye-opening.


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## JBroida (Sep 13, 2018)

RDalman said:


> Found a sample. Look at 7,30




Less common way of doing things for sure


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## RDalman (Sep 13, 2018)

Alright. I found it so useful (I do it myself) I thought it was standard way of doing things haha.


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## JBroida (Sep 13, 2018)

I think the most common is with a hammer and a chisel hammer depending on what you’re doing... I just went through the whole process a number of times in the last month in 3 regions


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## RDalman (Sep 13, 2018)

JBroida said:


> I think the most common is with a hammer and a chisel hammer depending on what you’re doing... I just went through the whole process a number of times in the last month in 3 regions


Yea prebending to get perfect straight quenched doesn't realistically happen either (so it's not like it removes the straightening steps), but I could get it so close the final straightening was much quicker to get just right


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## JBroida (Sep 13, 2018)

Yeah... I get it... straightening takes time and effort and can always break things... it’s a huge pain in the ass, but we all have to do it


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## Gjackson98 (Sep 13, 2018)

Yep I just confirmed it needs work lol.


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## merlijny2k (Sep 17, 2018)

I just rehandled a heavy cleaver, only to find out it was very badly warped when I was done. First tried hand bend. Total fail, couldn't get enough force. Second went with the three sticks method. Also failed. Probably need a bigger and better vice. Two and a half hours in and rather frustrated I just clamped it to the table and got out my hammer. Five minutes later all was well. My mother in laws chinese made heavy cleaver is most likely a LOT softer than your deba though. But still if you are willing to risk it hammering it isn't THAT hard.


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## JBroida (Sep 17, 2018)

merlijny2k said:


> I just rehandled a heavy cleaver, only to find out it was very badly warped when I was done. First tried hand bend. Total fail, couldn't get enough force. Second went with the three sticks method. Also failed. Probably need a bigger and better vice. Two and a half hours in and rather frustrated I just clamped it to the table and got out my hammer. Five minutes later all was well. My mother in laws chinese made heavy cleaver is most likely a LOT softer than your deba though. But still if you are willing to risk it hammering it isn't THAT hard.


deba have an urasuki (hollow ground back side) and that makes it a lot more complicated... a very different beast. Also, the steel is harder.


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## merlijny2k (Sep 17, 2018)

Wow Robin if you hadn't pointed out exactly where to look I would have missed the whole point!


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## merlijny2k (Sep 17, 2018)

Does depend a bit on whether or not you are bending towards or away from the urasuki? If you are bending towards it at the very least you have a flat surface to hit.


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## JBroida (Sep 17, 2018)

for sure... but in this case, the tip bends up and away from the back, so he'd have to hammer with the ura side down. Not a huge problem, but it requires a slightly different surface on which to hammer.


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## RDalman (Sep 17, 2018)

I would lay it bevel face side down and hammer inside the ura to fix this, bring the tip back in.


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## Gjackson98 (Sep 17, 2018)

Thank you all! 
So if I do end up using a hammer, I should place the knife on a hard and flat surface like the previous photo showed with the kanji side up and take the hammer to the tip?


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## RDalman (Sep 17, 2018)

I would have placed it right on the kanji, the kanji facing down, and hit in the middle until the bow is gone. Hollowed surface like a log or something might help and make it a little safer, however I typically do use my anvil and just be mindful of force/location.


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## Gjackson98 (Sep 17, 2018)

RDalman said:


> I would have placed it right on the kanji, the kanji facing down, and hit in the middle until the bow is gone. Hollowed surface like a log or something might help and make it a little safer, however I typically do use my anvil and just be mindful of force/location.


Got it! Thanks again


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## Gjackson98 (Sep 24, 2018)

I am back with some updates. 
I have tried both 3rods and hammer methods over the weekend. The Deba seems to stay at its original form. 
I had the knife sitting down with the Kanji side facing down, and I was hitting the top of the warping point.


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## Smashmasta (Sep 24, 2018)

To play at semantics, is this a "warp" or a "bend" (or are they synonymous?)? For some reason I had it in my head that a "bend" is when the spine axis is skewed, ie, to the left or right (or even multiple bends on the same spine axis), while a "warp" was when the edge to spine axis was skewed, such that you can see the side of the blade when looking straight down on it. A blade can also be both warped and bent, but they're not mutually inclusive. If they're the same, that's cool too, I just don't want to get confused. Also, can someone link this 3 rod method, I'd like to check it out?


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## Gjackson98 (Sep 24, 2018)

Smashmasta said:


> To play at semantics, is this a "warp" or a "bend" (or are they synonymous?)? For some reason I had it in my head that a "bend" is when the spine axis is skewed, ie, to the left or right (or even multiple bends on the same spine axis), while a "warp" was when the edge to spine axis was skewed, such that you can see the side of the blade when looking straight down on it. A blade can also be both warped and bent, but they're not mutually inclusive. If they're the same, that's cool too, I just don't want to get confused. Also, can someone link this 3 rod method, I'd like to check it out?


Its warp, if your holding the knife, the tip is warping to the right towards the kanji side.


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## Luftmensch (Dec 11, 2018)

Sorry for resuscitating an inactive thread...

... But my pedant-sense is tingling:



Smashmasta said:


> To play at semantics, is this a "warp" or a "bend" (or are they synonymous?)?



In the kitchen-knife world... I don't know? Perhaps there is some specific lingo I am unaware of.

I would say they are largely synonymous. They both indicate a deformation. If you want to get particularly particular than I would say that "warped" is a more generic term. I think you could use it to describe very complex deformations. "Bent" is effective at communicating a deformation on a single axis (for instance a twist, would not appropriately be described as a bend). I would also say the two describe difference processes of deformation. Blades "warp" from relieving internal stresses. Blades "bend" from mechanical stress.

So...

Looks to me like the deba warped (relieving of internal stresses) causing the tip to bend (primarily single axis deformation) towards the jigane.


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## faverodefavero (Dec 12, 2018)

Wooden hammer and nice beat up end grain wood board (maybe a copper hammer too). Hit it hard and many times on both sides... 

Best of luck man.


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## Gjackson98 (Dec 12, 2018)

faverodefavero said:


> Wooden hammer and nice beat up end grain wood board (maybe a copper hammer too). Hit it hard and many times on both sides...
> 
> Best of luck man.



Lol I have tried did not work a bit, the thing is too hard


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## Gjackson98 (Dec 14, 2018)

Since this topic has resurfaced, and the deba is curved so bad that I don’t know if there is anything I can use it for. 

I am open for more aggressive ideas, maybe heat it up with a heat gun then hammering it?


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## Mucho Bocho (Dec 14, 2018)

Send it to Jon @JKI


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## faverodefavero (Dec 14, 2018)

Maybe heat up just the spine where the warp is with a very focused small gas torch and keep hitting it hard.


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## faverodefavero (Dec 14, 2018)

You’ll have to fully repolish and resharpen the blade afterwards


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## Gjackson98 (Dec 14, 2018)

Mucho Bocho said:


> Send it to Jon @JKI


I have thought about it before, but the knife itself dosn't worth that much for me to be sending it around.. 
At this point it is more of a fun project than anything else.


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## Gjackson98 (Dec 14, 2018)

faverodefavero said:


> You’ll have to fully repolish and resharpen the blade afterwards


The finish won't bother me, I can always polish it later. I just want to make sure someone else has done it before lol 
I don't want to be the first guy trying it out and then end up burning the surface but the blade still warped.


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## faverodefavero (Dec 14, 2018)

Gjackson98 said:


> The finish won't bother me, I can always polish it later. I just want to make sure someone else has done it before lol
> I don't want to be the first guy trying it out and then end up burning the surface but the blade still warped.



Know some blacksmiths that do this on extreme cases when restoring blades that have some emotional value to the client. Never tried it myself...


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## Gjackson98 (Dec 14, 2018)

faverodefavero said:


> Know some blacksmiths that do this on extreme cases when restoring blades that have some emotional value to the client. Never tried it myself...


hahaha, if no one jump out to stop me, I will do it tomorrow and update you on it.


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## faverodefavero (Dec 14, 2018)

Gjackson98 said:


> hahaha, if no one jump out to stop me, I will do it tomorrow and update you on it.


Can’t wait to see if it works. Keep us posted.


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## Gjackson98 (Dec 14, 2018)

faverodefavero said:


> Can’t wait to see if it works. Keep us posted.


well do lol, I probably shoot a video too, to catch some live actions (hopefully I won't burn the house down)


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## faverodefavero (Dec 15, 2018)

Gjackson98 said:


> well do lol, I probably shoot a video too, to catch some live actions (hopefully I won't burn the house down)


Killing me with suspense... so: how did it go?


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## Gjackson98 (Dec 15, 2018)

faverodefavero said:


> Killing me with suspense... so: how did it go?



about to start on it on few min! Sit tight!


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## Gjackson98 (Dec 15, 2018)

and nope, it did not work lol


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## faverodefavero (Dec 15, 2018)

Gjackson98 said:


> and nope, it did not work lol


Nooooooooooooo...

Really? Blowtorch and all? It did anything?


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## Gjackson98 (Dec 15, 2018)

faverodefavero said:


> Nooooooooooooo...
> 
> Really? Blowtorch and all? It did anything?



I used blowtorch to heat up the blade for about 60seconds and hammered it a bunch. 
Nothing changed at all... 
Maybe I should heat it up more? I am not sure now


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## ThinMan (Dec 16, 2018)

I think you should take it to Mt Doom in Mordor and throw it back in to the fiery depths from which it came.


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## Gjackson98 (Dec 16, 2018)

ThinMan said:


> I think you should take it to Mt Doom in Mordor and throw it back in to the fiery depths from which it came.



That might be the best alternative. Where can I find a hobbit for the mission?


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## ThaFurnace (Dec 16, 2018)

Gjackson98 said:


> and nope, it did not work lol



Apply More heat!!


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## Gjackson98 (Dec 16, 2018)

ThaFurnace said:


> Apply More heat!!



Alright alright, I will give it another try


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## JBroida (Dec 16, 2018)

watching the thread is really hard for me... a lot of the advice in here is the polar opposite of everything i have learned in Japan. I have a lot of trouble seeing how this can be good advice.


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## ThaFurnace (Dec 16, 2018)

Just to be clear... my advice was given primarily just to see what happens next


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## Gjackson98 (Dec 16, 2018)

JBroida said:


> watching the thread is really hard for me... a lot of the advice in here is the polar opposite of everything i have learned in Japan. I have a lot of trouble seeing how this can be good advice.



Jon what would you recommend in this situation?


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## JBroida (Dec 16, 2018)

A chisel hammer and a bit of practice


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## faverodefavero (Dec 16, 2018)

JBroida said:


> A chisel hammer and a bit of practice


The practice is the hard part...


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## Gregmega (Dec 17, 2018)

Jon doesn’t like hobbits. Or Mordor.


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## JBroida (Dec 17, 2018)

Gregmega said:


> Jon doesn’t like hobbits. Or Mordor.



Short, hairy, and loves food? Bro... hobbits are MY people. [emoji13]


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## Gregmega (Dec 17, 2018)

JBroida said:


> Short, hairy, and loves food? Bro... hobbits are MY people. [emoji13]



[emoji23][emoji23][emoji23][emoji41]


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## Gjackson98 (Dec 17, 2018)

I guess I am just waiting on a white wizard to come save my azz now


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## faverodefavero (Dec 18, 2018)

Gregmega said:


> Jon doesn’t like hobbits. Or Mordor.


Hahahahah


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## minibatataman (Dec 18, 2018)

You said it yourself. The knife isn't worth enough to send to Jon for fixing. It's the perfect one to try his method on and get practice. That way if this happens with something alot more expensive down the line you know what to do


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## Gjackson98 (Dec 18, 2018)

minibatataman said:


> You said it yourself. The knife isn't worth enough to send to Jon for fixing. It's the perfect one to try his method on and get practice. That way if this happens with something alot more expensive down the line you know what to do



Yep yep, Jon has been giving me kindly advices here for me to get started. Real gentleman!


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## Bodine (Dec 18, 2018)

You just need a bigger hammer.


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## Gjackson98 (Dec 19, 2018)

Bodine said:


> You just need a bigger hammer.



And I might need to go lift more weights


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## Luftmensch (Dec 20, 2018)

Gjackson98 said:


> I used blowtorch to heat up the blade for about 60seconds and hammered it a bunch.



Jon has kindly given very specific advice:



JBroida said:


> watching the thread is really hard for me... a lot of the advice in here is the polar opposite of everything i have learned in Japan.



That is to say you must freeze the deba and then use the non-bent part of the deba to caress the hammer


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## HRC_64 (Dec 21, 2018)

Bodine said:


> You just need a bigger hammer.



I know people are kind of being jokey, but its worth keeping in mind any given weight
used a little more precisely is a viable alternative....

John's advice was to use a properly shaped hammer (such as a chisel point)
to put more force onto a smaller area, 

AFAIK these are typically lighter hammers (300g) vs 
heavier (1-2kg), even a standard hammer is 500g


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