I think I have a screw too tight

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Delbert Ealy

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Things have been picking up for me, and that is great in most ways.
However even though I have been devoting a bit of shop time to my own pursuits, it is normally in making a few extra knives for the market. It is not bad, it is what I want to do and to keep doing.
In the past few days however, I have again felt the impulse to do something really strange, outside my normal.

I had this idea more than a year ago to make a bronze kitchen knife. I have made over a dozen knives out of bronze and it is a really cool material to work with. It is not like working with steel at all. Yes it is a metal alloy, but that is where the resemblance ceases. It has been many years, but I am feeling an increasing compulsion to make something that is really out there. Not only that, I would really like to have one of my own knives to use. I do have one, but it is from the very beginning and without all of the design changes I have made since.
I know that all of our knives are now made of steel with all of its benefits, but our ancestors used bronze tools with great effectiveness for thousands of years.

To give you an idea of my skill with bronze, I have made knives out of bronze that would shave hair easily.
I am confident that I could make an effective bronze kitchen knife, the only real issue is edge durability.
I know the bronze blades would have to be sharpened a bit more often.

What do you guys think, am I turned a bit too tight?
Thanks,
Del
 

larrybard

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Del, With all respect, I don't understand why you're even asking the question. It seems clear that it's something you really want to do. And the only supposed downside is that the knife you have been thinking of making, for over a year, would probably have to be sharpened relatively frequently? I think that until you make it you will regret not engaging in what almost certainly will be an enjoyable and satisfying project. Have fun!
 

WildBoar

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For Dog's sake, do it man! :doublethumbsup:
 

chefcomesback

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Del , I would like to see a bronze knife done similar style when people were using bronze rather than a modern kitchen knife.
maybe unfinished end at the bottom of the handle maybe some brass to give bling


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chinacats

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I think loose screws are great! Can't wait to see a WIP?
 

daveb

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If you've got a screw loose, then you're in good company. The difference between you and us mere mortals is that you have the talent to realize some of the off the reservation ideas. Pls send pics.
 

mkriggen

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I think if you were to make a kick-ass bronze suji, edge retention would be a much smaller consideration.

Be well,
Mikey
 

Delbert Ealy

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Thanks for the encouragement guys.
In my family on my mothers side in particular there runs a streak of stubbornness that in some can be more than a little off putting. I have it too, however in my case, through the crucible of learning to make knives, has been morphed into a determination of accomplishment. By that I mean that once I set my mind to a task, I make it happen. I am just glad I have a base of fans of my work, that it allows me to live and thrive.
Bronze to be ordered first thing on Monday morning.
I will indeed put up a work in progress for this one. With the stock I have in mind, I think I'll start with a 210 gyuto. I think that will be a good fit for my kitchen. I will want to do quite a bit of testing before I make any for the public market.
If I am satisfied it will open a potential for mokume blades with a bronze core.
Thanks,
Del
 

snowbrother

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I think it is a brilliant idea. Other than cooking and knives, my next biggest interest is steampunk. That is why I love copper so much as accents/decorations on knives. But that also means that I have always had this interest in an all bronze/copper kitchen, including spoons, pans and knives. I haven't done this because of a) cost and b) I love cooking too much in rolled carbon steel and cast iron pans. But the idea of a bronze knife is just too cool not to do it.
 

Mrmnms

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Del, are there certain type of Bronze alloy that approach the hardness of steel? What type of bronze are you considering? Looking forward to seeing this.
 

Delbert Ealy

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The alloy that I will be using for these knives will be 510. It is commonly called phosphor bronze. The composition is roughly 95% copper 5% tin and just a bit of phosphorus. I can get this in spring hardened stock, which means a bit less work for me and that the finished product will have a hard edge and a springy back. I would like to use an alloy with a bit more tin, but finding the proper alloy without any extra alloying elements and in the proper size stock can be a challenge. I have used this alloy before and am very comfortable with it.
Bronze alloys will never approach the hardness of steel, mostly because the mechanisms for hardening are so different, but it is still possible to make an excellent bronze blade that will outperform a poorly made steel one.
Thanks,
Del
 

chinacats

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Would this be a knife where differential hardening could be helpful?
 

malexthekid

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What is the hardness of bronze like compared to steel? Is there much of a differences in working with them?

Love this idea l, will definitely be interested in watching this progress
 

Delbert Ealy

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Would this be a knife where differential hardening could be helpful?
This is the type of knife where differential hardening will indeed be used. On most ancient pieces the back of the knife or the center in double edged pieces would be soft, generally cast with a thick edge that was then hammered down. this type of hardening is called work hardening or strain hardening. It has practical limits in that if you go too far the material will fail.
For these reasons you rarely find historical blades that are more than 2 feet long, although I have seen a few beyond that. I am endeavoring to push the limits of this material by using partially hardened stock to start with that is stronger and so I can use sizes of stock that are familiar.
The edges will be hammered down to strengthen them further and then the final shaping will occur.
It is a quite delicate process, because you can be one hammer stroke from destroying a blade.

These blades will not be subject to any heating at all, because heating relaxes the strain on the bronze and it will become softer and have less wear resistance.
It is this tension within the structure of the metal that causes it to be hard.
Good modern steels properly heat treated will always beat out bronze. The hardness does not compare. However, like I have said before, that does not mean that useful tools cannot be made from it. I am sure that many during the transition from bronze age to iron age would prefer the bronze. When you have had 3000 years to perfect a technology, the results can be pretty fabulous. In the early years of Iron and steel technology, the results were likely pretty crude. I have made bloomer steel and I can tell you that when it first comes out of the fire it looks like crap. Even the first few welds it is crap. The more you work it the better it gets. Compare that to a methond where you melt the metal mix down, cast your blade and hammer the edge and you are ready to go.
The way of thinking had to change entirely. You go from hammering on edges to harden them to taking a hot bar of metal and cooling it rapidly to harden. That is a serious change in thinking.

More later on.
Thanks,
Del
 

malexthekid

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It sounds like a lot of fun playing around with the different method of hardening, it reminds me of all my material science classes at uni. Learning about work hardening and quenching etc.
 

WingKKF

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If you're going to use the knife on food I hope you make very sure the bronze you use doesn't contain any lead.
 

Delbert Ealy

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If you're going to use the knife on food I hope you make very sure the bronze you use doesn't contain any lead.

An understandable concern. My source for this material provides msds and melt data analysis charts upon request. That is one of the issues with choosing the proper alloy to work with, as well as how it will perform.
Del
 

Delbert Ealy

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It sounds like a lot of fun playing around with the different method of hardening, it reminds me of all my material science classes at uni. Learning about work hardening and quenching etc.

I sometimes wish I had spent more time in school. A high level materials science class right now sounds like a load of fun. I had to aquire this part of my knowledge hands on.

I am just glad I made the mistake of trying aluminum bronze early on. That stuff is absolute s**t for blades, hot forging and all the fun stuff to make out of bronze. I will never allow that stuff in my shop again.
Del
 

Delbert Ealy

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I got the bronze in yesterday, and I did start on this. I will be posting pics later, going to spend some time with family.
Del
 

malexthekid

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Can't wait to see the project progress.

And sit back, relax and enjoy the time with the family.
 

ejd53

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This ought to be fun. Bring it on!!! :bliss:
 

Sabaki

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This is the type of knife where differential hardening will indeed be used. On most ancient pieces the back of the knife or the center in double edged pieces would be soft, generally cast with a thick edge that was then hammered down. this type of hardening is called work hardening or strain hardening. It has practical limits in that if you go too far the material will fail.
For these reasons you rarely find historical blades that are more than 2 feet long, although I have seen a few beyond that. I am endeavoring to push the limits of this material by using partially hardened stock to start with that is stronger and so I can use sizes of stock that are familiar.
The edges will be hammered down to strengthen them further and then the final shaping will occur.
It is a quite delicate process, because you can be one hammer stroke from destroying a blade.

These blades will not be subject to any heating at all, because heating relaxes the strain on the bronze and it will become softer and have less wear resistance.
It is this tension within the structure of the metal that causes it to be hard.
Good modern steels properly heat treated will always beat out bronze. The hardness does not compare. However, like I have said before, that does not mean that useful tools cannot be made from it. I am sure that many during the transition from bronze age to iron age would prefer the bronze. When you have had 3000 years to perfect a technology, the results can be pretty fabulous. In the early years of Iron and steel technology, the results were likely pretty crude. I have made bloomer steel and I can tell you that when it first comes out of the fire it looks like crap. Even the first few welds it is crap. The more you work it the better it gets. Compare that to a methond where you melt the metal mix down, cast your blade and hammer the edge and you are ready to go.
The way of thinking had to change entirely. You go from hammering on edges to harden them to taking a hot bar of metal and cooling it rapidly to harden. That is a serious change in thinking.

More later on.
Thanks,
Del
you described my question i was about to ask... if bronze would benefit from work hardening (gentle cold forging?) to get it harder/springier, it did!

depending on how much you hammer the edge, the tip will tend to rise upwards the spine, a bit like a Katana sword.
But i'm pretty sure you got this allready covered:)

similar method can be done with ferritic-austenitic steel? and is the only way to get it harder, have you ever worked with this steel?

Interesting stuff to take on for sure, looking forwad to see the result :thumbsup:
 

EdipisReks

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No idea about a bronze knife, but I was at an upscale independent kitchen store in Columbus, Ohio, yesterday, and they had several of your knives on display, in a new artisan section, and I wanted to say congrats, Del!
 

Delbert Ealy

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No idea about a bronze knife, but I was at an upscale independent kitchen store in Columbus, Ohio, yesterday, and they had several of your knives on display, in a new artisan section, and I wanted to say congrats, Del!

Thanks,
Nancy is one of only two retailers that carries my stuff. She is a pretty cool gal, and a joy to work with.
Del
 

EdipisReks

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Thanks,
Nancy is one of only two retailers that carries my stuff. She is a pretty cool gal, and a joy to work with.
Del
She has a gigantic and friendly dog, as well, who makes visiting the store a lot of fun.
 

Lefty

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Nancy is amazing. Del, you're alright too. ;)
 

Lefty

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Nancy is amazing. Del, you're alright too. ;)
 
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