San mai - Enlighten me please

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Dhoff

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So, San mai stainless knives. How do these compare to fully stainless and carbon knives? It seems to bring the best of the two worlds, what is the drawback?

I have tried searching both google and this forum but this seems such basic knowledge its actually hard for me to find
 
drawbacks:
stainless cladding can sometimes be gummy to sharpen
stainless cladding can be easily scratched if soft, but not common
stainless clad carbon is often pre-laminated from factory, not by the craftsman, not necessarily bad
if the craftsman laminates it, it adds on a lot of cost in labor relative to carbon iron sanmai by hand, except for some steels like 52100
 
With a hard carbon core in a double-bevelled blade San-mai as the best of both worlds makes a lot of sense.
If the stainless cladding scratches easily, they are taken away just as easily. With unexpensive blades coarse ScotchBrite (brown/mauve) keeps the look acceptable and not too vulnerable in daily use.
Make sure to thin when sharpening, otherwise the day will appear that some of the cladding has become a part of the edge.
See it as a pencil: the soft wood protects the core, but when you sharpen you take away some of the wood as well to free a new part of the core.
 
So, a few new questions in the subject. As I have learned a bit more I see a few different San-mai "constellations" and I wonder why each are made:

1) Aogami/Shirogami core with soft carbon steel cladding: What is the practical function of the cladding? It looks awesome but... whyyyyy?

2) Aogami/Shirogami core with stainless cladding: This one makes sense to me.

3) Stainless core with stainless cladding: Again why?

4) Stainless core with semi-stainless cladding: Again why?

5) Semi stainless core with stainless cladding: Makes sense.

Also, someone mentioned that San-mai knives can be bend using only the fingers if the core is (too) thin. Which makers could this be?
 
I'm not an expert, but here are my best guesses at answers to your questions-

#1: The tougher outer cladding helps prevent cracking of a harder but brittle core. The cladding may be CHEAPER than the high quality core steel too.

#2: Yes, it makes sense for use by people who are not ready to do the care required of an a particular non rust resistant high Carbon steel core/non rust resistant softer Iron cladding blade but want a hard Carbon steel cutting edge. See here for my adventure in learning about taking care of these:

https://www.kitchenknifeforums.com/threads/who-made-these-petit-knives.39374/


#3: A couple of possibilities- People wanted the look of stainless damascus patterned cladding and the performance of a hard, high carbon stainless/semi stainless core?.

#4: Could you point out where you found this combination? I haven't seen it done that way.

#5: Yes, makes sense.
 
Thank you Bert, I will see if I can find an example of #3, I remember it from a thread where one commented it made no sense and another said (with me paraphrasing) "This does not even merit an answer"
 
You’re over thinking it.

Cladding is to protect the high carbon core and reduce costs. Doesn’t matter if it is stainless or iron cladding on top of a that.

Which type of steel to get depends on personal preferences and the weight of your wallet.
 
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I also think it's traditional. In times before steel was harder to come by than it is today. So the good steel that had just the right amount of carbon in it was rare. So they used less appropriate material to bulk it up
 
No. They were made out of tamaganhe(spelling?). The steel itself had varying layers of hardness throughout the billet but they worked on getting the hardest steel in the core
 
Didn't swordmakers use sanmai the other way around: soft core, hard cladding?
No. They were made out of tamaganhe(spelling?). The steel itself had varying layers of hardness throughout the billet but they worked on getting the hardest steel in the core
nope, katanas can be made any number of ways, most commonly by kobuse method or by stacking the tamahagane billets and forging them in a way the soft steel is wrapped by the hagane.
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I'm not a blacksmith/knife maker but would the "forgablility" (just made that word up) of the metal play a factor in choosing the clad material? Do certain claddings weld better to certain steels?

For example, Shigefusa doesn't used grinding wheel, and uses a Zen to remove metal, so for them it makes more sense to use a softer iron clad vs harder stainless ?

Maybe some makers or people in the field can chime in here with much more expertise than me.
 
I've seen it mentioned elsewhere that the iron cladding over hard core makes it easier to straighten the blade after heat treat.
 
labor cost is the most expensive part of a $300-500 knife...the steel cost is abotu $10 usd.

its faster and less wear on the belts and stones to thing/grind on un-hardened iron or mild steel,
especially during finish sharpening/shaping, saving alot of labour and consumable abrasives
not to mention simply using less production time so faster overall.

Monosteel is still used in honyaki, but other than that, it's limited to certain production environments--
primarily those that are automated at least in part.

That being said, san-mai is no longer any gauranteel that the knife is substantially "hand-forged",
even expensive knives in $500 price range are using factory billets/clad, and I'm guessing anything
using PM steels and most if not all more plain-vanilla stainless is also pre-fab bar stock.

Its very difficult to get good weld on the cladding with stainless core when doing it by hand,
in open air, etc ... and needs alot more than general skill with blacksmith tools.
 
Its very difficult to get good weld on the cladding with stainless core when doing it by hand,
in open air, etc ... and needs alot more than general skill with blacksmith tools.


I think you have to do it in a vacuum for SS to bond to other stainless. I think at least.
 
1) Aogami/Shirogami core with soft carbon steel cladding: What is the practical function of the cladding? It looks awesome but... whyyyyy?

Not an expert here, but a few guesses:
  • Soft carbon cladding allows correcting a slightly bent knife, either during manufacture or post-sale. I had to fix a knife tip that was slightly bent in shipping damage. It was a Takumi Ikeda gyuto in AS with soft "damascus" carbon cladding. Bending the tip was easy, probably much easier than if it had a "springier" stainless steel cladding.

  • Stainless over a carbon core still means you have to dry the blade edge carefully before putting it away, so it's not that much extra work to dry carbon cladding. Stainless cladding just isn't a huge advantage here.

  • Some people like the look of a well-developed carbon patina on the full blade edge. Also some "damascus" patterns may only be available in carbon cladding, like the sumanigashi pattern on my Yoshikazu Ikeda knives. Stainless cladding is (usually) boring, with a few pattern-weld exceptions like the Shun "Dual Core" series.
 
thank you everyone for your indput and knowledge.

I agree on all your points paraffin. The only reason I would favor the stainless cladding is limit or avoid taste being affected when cutting e.g. strongly acidic fruits.
 
Personally I think claddings are mostly done to cut costs. I can imagine knife steel costing maybe 5-20 times more than the claddings, no matter what claddings.

Back in the middle ages knife steel was scarce so they had to make the most out of what they had.
 
I’ve heard that carbon steel/iron stays warm for a longer time than stainless, making it easier when smithing. Strike when the iron is hot! I’m not sure I remember the exact words and it was filtered through a translator, but I think Yu Kurosaki mentioned that blades with aogami super core and stainless cladding were among the hardest ones to make, but they ”had to” since that combo was in such high demand. Can’t remember exactly why it was so hard, but probably lots of different reasons.
 
I have feeling the the actual stainlessness of stainless is what makes it hard. stainless forms an oxide of chromium oxide on the steel, this creates a barrier to the outside world and prevents corrosion. I have heard you need to weld ss to carbon and ss to ss in a vacuum or protective atmosphere otherwise they wont weld together.
 
Even using pre made billets if the maker has forged it to shape it's still a hand forged knife. And realistically being forged doesn't make it better/more valuable anyway. All knives are made of forged steel whether its stock removal or forged to shape.
Yes stainless forging needs an oxygen free environment. I imagine for a home Smith or non steel factory you could put your steel in a can, forge weld it, and remove the can
 
Interesting topic. From what I read on the forum, Teruyasu forge weld stainless cladding instead of using prelaminated bar stock. I wonder if he has an oxygen free environment.
 
Yes, disappointing to hear Konosuke are buying in predominated
Interesting topic. From what I read on the forum, Teruyasu forge weld stainless cladding instead of using prelaminated bar stock. I wonder if he has an oxygen free environment.
Was thinking same thing.
 
At work used mono steel carbons. Masamoto, Konosuke, Sakai Yusuke. Carbons used a lot every day just wash & wipe down at end of shift. They form a patina rather quickly cutting all kinds of food. I would clean my Yanagiba's, however fish does not patina as much as other foods.

Used to agree with the late great KCMA that mono is better than San Mai. Have changed my opinion esp. since makers like Kochi and others make durable KU and Nashiji stainless clad. Most of the knives recommend are carbon core stainless clad. One advantage is price you can get Blue#2 core blades rather cheap for a quality knife.

The downside is softer stainless cladding gets scuffed up easy, but most cooks don't give a rip what their knives look like so long as they cut good. The example Benuser made with a pencil is a good one. Using a lower thinning angle before your final bevel every time you do full sharpening helps keep you ahead of the clad line.

At home still have a few mon steel smaller knives, since they are not used like at work they require more attention so they don,t rust. Other home blades are san mai like Kochi, TF white #1, Ginsan Tanaka, Iron clad Watanabe.
 
Thank you sir. I must admit I like the look of stainless clad meeting an edge with good patina!
 
The site that shall not be named has forum, where konosuke (kosuke) talks about their knives in a thread about their knives.
 
Thank you sir. I must admit I like the look of stainless clad meeting an edge with good patina!
I should add that the patina returns almost immediately after a full sharpening. Much quicker than it occurred with a brand new knife. Am no metallurgist, don't know why.
 
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