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Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 1:54 am

Hi. I'm seeing different types of "stainless-covered" knives. Sometimes called san mai ( I think this is where the cutting edge and top of spine of carbon blade is exposed. Then sometimes I see the term "clad". Other times it's described as xxxcarbon with damascus, etc. Sometimes I see that the knife consists of a "3-Pc." construction. Sometimes a "folded" construction, etc. etc.

I read in a post that some don't care for the san mai construction, but can't seem to find much information concerning the different SS cladding types, which cladding is best, etc.

Any explanations would be appreciated. I'm sure there's a few others confused about this, too. Then again.....

Thanks much for any help.

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 2:27 am

OK! I think others will do better than I can but here is what I know.

Clad knives, "awase" in Japanese, are knives that have a hard steel core— usually carbon steel—clad over with a softer layer—which can be iron or stainless steel or any number of things. Clad knives come in three types: San-mai, Warikomi, and Ni-mai. Below is a nifty image that illustrates each one.

Image

As you can see, San-mai has a softer layer (jigane) on either side of the harder core (hagane), but not over the spine; Warikomi has a similar cladding but with the spine covered as well, and Ni-mai is a cladding used for single bevel traditional knives, in which only the cutting side is clad with jigane.

There are several styles in which knives can be clad, two of the more popular are kuro-uchi and damascus.

Kuro-uchi is a type of rustic look in which blades aren't "finished" except for on the edge. It can be clad in a black-ish lacquer, a baked-on dimpled look, or in forging iron, like this Takeda Gyuto.
Image

Damascus is a distinctive "wavy" pattern achieved by a process of folding the steel onto itself several times over.
Image

3-pc construction is referring to San-mai, and often to Warikomi as well. Hope this helps a little.

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 2:34 am

Whoops, forgot, you can also have just plain stainless steel cladding too, like this Masakage petty.

Image

There are several other ways san-mai can be used, but this is just a quick primer. As far as which cladding is best, it's really hard to make any hard and fast rules about that, because the quality of the knife is dependent on many other factors, including the skill of the individual blade smith and the process they used to achieve it; grouping all kuro-uchi finishes together to objectively say "they are better than 'x'" is a futile exercise.

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 5:14 am

Also MELAMPUS wrote in another thread < > “Laminated” is a blanket term for “clad”

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 6:27 am

that HHH knife isn't clad in anything. it's damascus.

but there are knives clad in damascus like the more common shun knives.....

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 3:11 pm

I just grabbed the first Damascus pattern I saw, didn't even think to check if it was clad or not. Oh well.

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 3:56 pm

no worries =D

randy does make knives clad in damascus but he does all damascus as well.

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 4:33 pm

Hi. I'm seeing different types of "stainless-covered" knives. Sometimes called san mai ( I think this is where the cutting edge and top of spine of carbon blade is exposed. Then sometimes I see the term "clad". Other times it's described as xxxcarbon with damascus, etc. Sometimes I see that the knife consists of a "3-Pc." construction. Sometimes a "folded" construction, etc. etc.

I read in a post that some don't care for the san mai construction, but can't seem to find much information concerning the different SS cladding types, which cladding is best, etc.


San-mai, clad, warikomi, etc. all refer to essentially the same thing.....that the knife is made up of a core steel and is clad in something else.

That cladding can be damascus like the Shun's, stainless like the Hiromoto AS's, or carbon like the Takeda's....can also be carbon damascus like the Tanaka's.

Stainless cladding can be any number of soft stainless steels....what it is really shouldn't be of much or any concern.

Some damascus cladding (carbon or stainless) can provide drag if etched in a way that might create such a thing....not very common.

Folded.....not sure about that one. Some damascus is "folded"....but I don't think it would refer to anything as it pertains to cladding.

Re: Please explain San Mai, Clad, etc.

Thu Mar 14, 2013 5:11 pm

It seems I remember an article describing a "folded" clad as having a softer steel folded over a harder steel covering the spine and cutting sides too. But that could also be my imagination. :?

Re: Please explain San Mai, Clad, etc.

Sat Mar 16, 2013 4:06 am

The previous posters seem to have provided pretty good explanations, but I wanted to add a few belated points on the purpose of lamination and Damascus steel.

Most traditional Japanese blade manufacturing involves welding a piece of high-carbon steel that forms the edge to a piece of low-carbon steel or wrought iron that provides support to the more brittle high-carbon steel. The hagane (which means "edge metal") of a cutting tool is usually a piece of steel that, when crystallized to the extent Japanese tools usually are, would be very rigid and brittle. Traditional Japanese blade technology addresses this problem by welding that hard steel to a body of the blade made of a less carburized steel or wrought iron (the "jigane") which is more ductile but won't hold a sharp edge. My understanding is that the softer metal absorbs the shock of sudden stress to the blade, so you don't shatter your chisel when you hit it with a hammer or break your knife when you drop it. The way in which the edge steel is welded to the body steel accounts for the terms mentioned: ni-mai and san-mai just mean "two-layer" and "three-layer", respectively, so obviously a billet of steel made for a double-bevel knife would have the edge steel in the middle of two layers of soft steel for the sake of symmetry and a single-bevel would have the edge steel on one side of a layer of soft steel. "Warikomi" means, as best I can tell, "wedged" or "inserted", which I believe refers to the method of splitting open or folding the soft steel to create a fold into which the edge steel is inserted. Interestingly, the techniques of forge welding hard steel to soft steel or iron were fairly common in western tool making before the advent of modern steel production methods that made steel more homogeneous and less brittle. Nowadays I suspect much of the purpose of having two different types of steel in stainless knives is largely cosmetic (especially in the "Damascus"-clad knives) but it does offer the possibility of having most of the knife stainless with a high-carbon edge.

"Damascus" steel is produced in a number of ways; I believe the beautiful nakiri pictured above, with its extremely regular, fairly thick layers, was made by welding several layers of two different types of steel together and drawing them into a bar--this technique is more accurately referred to as "pattern welding", and describes most "Damascus" steel produced with modern methods. The patterns of middle-eastern steel that were originally referred to as "Damascus" in the Middle Ages were made by drawing an ingot of crucible steel, which had pockets of different carburization levels because of the method of its production, into a bar. Medieval Japanese swords also have a similar, finer pattern in their steel (referred to as ji-hada). This grain is produced by reducing the irregularity and impurities in crude crucible steel by welding it to a piece of wrought iron and folding and welding the resulting bar several times. The refined steel would have been used as the steel for the edge of swords, rather than the softer core.

You can see the contrast between the hagane and the jigane on most of the knives pictured on CKtG. Apart from pattern-welded steels, most of the differences in the appearance of jigane, like "kuro-uchi" have to do with finishing rather than the metal itself. An exception would be the Itto-Ryu knives like this: http://www.chefknivestogo.com/rehafowh1gy2.html, whose jigane is actually wrought iron (a form of iron that was ubiquitous a hundred years ago, produced by drawing pig iron out to create a bar with fewer inclusions and a linear grain structure, with almost no carburization). I'd spring for one of these in a heartbeat just because I love the way wrought iron looks, but they have an asymmetrical handle and I'm left-handed, so I'll have to settle for a moritaka aogami super (sad, I know).
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