knife straightening and hizumibo

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Kkuubbaa

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hey
i have a question. can this be straightened? any advice? carbon steel. could it be straightened using hizumibo or is the steel too thick? and one more question. has anyone made hizumibo themselves because i cant find anywhere what are the dimensions of the holes in the wood. does anyone have any dimensions of hizumibo that they could share? best regards
 

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Yes it's straightenable. Cut slot width to fit the spine of the blade near tip and near heel. Just make it strong enough lol, and wide enough so the stick doesn't snap. I have measurements posted somewhere here but a bigger stick might have helped. It will require a lot of effort to straighten. Everytime I do a deba I almost cry or at least I wince, it's a lot of force and I haven't slipped yet ....
 
Make sure you check along the edge before you mess with it. More often than not Deba come with a propeller twist with the spine going right and the edge being straight or going the other way. A propeller twist on a cheap deba is no problem and doesn’t interfere with honbazuke and use.
That said bending a deba to the left is doable, bending them to the right causes creasing of the jigane.
 
Answers to your questions.

Yes.
Yes.
Cut them about the right size, bigger than small but not too big.

Edit: But there are some other ways to straighten too.



I found this video. Isn't the deba too thick to bend like that with your hand? Can you write how else you can straighten this deba. I straightened one old knife using a hammer gently
 


I found this video. Isn't the deba too thick to bend like that with your hand? Can you write how else you can straighten this deba. I straightened one old knife using a hammer gently

We have had a lot of threads on this over the years. Use the search tool. This is a good one:

https://www.kitchenknifeforums.com/threads/have-you-straightened-knives-before.70354/

You can also search the site on Google by adding "site:kitchenknifeforums.com" to your search terms.

This is the search
"straighten deba site:kitchenknifeforums.com"

https://www.google.com/search?q=str...AMAiAYBkgcAoAeHAQ&sclient=mobile-gws-wiz-serp
 


I found this video. Isn't the deba too thick to bend like that with your hand? Can you write how else you can straighten this deba. I straightened one old knife using a hammer gently

Some blacksmiths I deal with ask what length and weight deba I want, so the thickness can vary, so as you said, some can be too thick to easily bend by hand. A carbide hammer is great for straightening and sometimes I've had luck with a wooden mallet. Also the longer the magebo the more torque you have ...(I need to make a longer one🤔).


But as @Lurkernomore said you have to check the edge as this is more important than the spine.
Make sure you check along the edge before you mess with it. More often than not Deba come with a propeller twist with the spine going right and the edge being straight or going the other way. A propeller twist on a cheap deba is no problem and doesn’t interfere with honbazuke and use.
That said bending a deba to the left is doable, bending them to the right causes creasing of the jigane.
I've got a 30 year old Mundial chef knife, 4-5 mm thick at the spine, and I've bent it from crushing garlic so you can bend a knife with garlic cloves
 
The itemI acquired came with a dimension diagram.
PXL_20250113_070406337~2.jpg

2025-01-13 160931.png



In this video, he mentions that when bending to the right side (the soft iron side), he sometimes uses a rod, but a rod makes fine adjustments difficult. He also says that when use with a hammer instead of a chisel hammer, hitting the soft iron side causes the hard steel to stretch and become more prone to cracking. In comparison, hitting the ura is relatively less likely to cause cracking.
 
The itemI acquired came with a dimension diagram.
View attachment 380547
View attachment 380548


In this video, he mentions that when bending to the right side (the soft iron side), he sometimes uses a rod, but a rod makes fine adjustments difficult. He also says that when use with a hammer instead of a chisel hammer, hitting the soft iron side causes the hard steel to stretch and become more prone to cracking. In comparison, hitting the ura is relatively less likely to cause cracking.

Hi! Where did you order/purchase that one from? :)
 
Ah! Domo arigato gozaimasu! Didn't notice that you were from Japan (or, in Japan?) :)

Hmmm, I need to decide whether I should have one made here (it is fairly simple, after all), or order one from the place you linked.

I have a deba that I bought it like 25 years ago but it was forgotten in storage for most of that time. I ran into it at my mother's place during Christmas, took it back home, and noticed that it is quite bent/curved... since it was a cheap one I thought it might be a good knife to practice straightening on.

Anyway, once again, thank you for the information, much appreciated!
 
I bought it here.
However, in another video, the man in the video said he didn’t like the X-shaped grooves.
He mentioned that having wide grooves in the same direction as the others makes it easier to bend a deba knife.
https://item.rakuten.co.jp/sakai-fukui/4941019062176/
I like the x shaped ones a lot better for thick knives. You get way better leverage than with perpendicular slots, which are mainly good for bending thin knives back at the tang. For bending deba at the tang I take it off and use a hammer.
Actual bends in the blade itself I also take out with the x slot regardless of thickness because it applies force over a wider area and allows oft better dosage of it. With perpendicular slots you always risk introducing very localized overcorrections and ending up with a bunch of small bends rather than the smoothing out you want.
In Sakai most people use the x slot for 99% of jobs.
 
I like the x shaped ones a lot better for thick knives. You get way better leverage than with perpendicular slots, which are mainly good for bending thin knives back at the tang. For bending deba at the tang I take it off and use a hammer.
Actual bends in the blade itself I also take out with the x slot regardless of thickness because it applies force over a wider area and allows oft better dosage of it. With perpendicular slots you always risk introducing very localized overcorrections and ending up with a bunch of small bends rather than the smoothing out you want.
In Sakai most people use the x slot for 99% of jobs.
Agreed, I use the x slot for the vast majority of correction and only use the slots when I need to target a very specific spot on the blade.
 
Ah! Domo arigato gozaimasu! Didn't notice that you were from Japan (or, in Japan?) :)

Hmmm, I need to decide whether I should have one made here (it is fairly simple, after all), or order one from the place you linked.

I have a deba that I bought it like 25 years ago but it was forgotten in storage for most of that time. I ran into it at my mother's place during Christmas, took it back home, and noticed that it is quite bent/curved... since it was a cheap one I thought it might be a good knife to practice straightening on.

Anyway, once again, thank you for the information, much appreciated!
The link I shared probably doesn’t support international shipping, and even if you ask someone to help, it would cost around $100. So, it might be better to make one yourself.
I initially thought about making one too, but I gave up because buying a saw, a chisel, and wood seemed like a hassle.
 
I like the x shaped ones a lot better for thick knives. You get way better leverage than with perpendicular slots, which are mainly good for bending thin knives back at the tang. For bending deba at the tang I take it off and use a hammer.
Actual bends in the blade itself I also take out with the x slot regardless of thickness because it applies force over a wider area and allows oft better dosage of it. With perpendicular slots you always risk introducing very localized overcorrections and ending up with a bunch of small bends rather than the smoothing out you want.
In Sakai most people use the x slot for 99% of jobs.
Agreed, I use the x slot for the vast majority of correction and only use the slots when I need to target a very specific spot on the blade.
I also usually prefer using the x slot, but he is a professional sharpener from Sakai who sometimes sharpens honyaki knives, so I shared his opinion. I don’t have much experience fixing thick blades, so your insights are valuable to me.
 
I also usually prefer using the x slot, but he is a professional sharpener from Sakai who sometimes sharpens honyaki knives, so I shared his opinion. I don’t have much experience fixing thick blades, so your insights are valuable to me.
Sharpeners have one advantage over everyone who works on finished knives: they can use the stick and a hammer together. Smooth, slight bends they take out with a hammer while the stick is for more localized jobs. Once the knife is finished you can’t use a hammer anymore so for me it’s the x.
Another thing to consider with perpendicular slots is the width of the slot relative to the thickness of the blade. The less of a gap there is the more localized your bending will be (down to right at the corner of the stick that the knife gets pushed against). Widen the gap and the knife will be rested against two diagonally opposing corners of the slot, sit at an angle and bend around the corner of the stick with a slightly bigger radius.
It’s not an exact science but that’s kinda what happens and makes sticks feel different from each other. I like my perpendicular slot at about 7mm. You could fit a deba in there but I can’t bend them that way, too weak and arms at awkward angles.

Anyway, sticks have to be tried out in person and you’ll likely end up making three or four until it’s all dialed in. I made my first one out of an axe handle.
 
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