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chinacats
03-08-2013, 03:35 AM
So this came up in another thread and I am curious as to the benefits of either monosteel or sanmai knives. I own a few of each and while they are different, I am not so sure what is related to the individual knife and what is related to the construction.

I've used lasers made of both and thicker knives made of both. I enjoy the sound of the monosteel when flicked while the sanmai seems to kind of thud. :clown:

In the end, the best cutters I've used have been of both types. In trying to figure out the specifics before ordering a full custom knife, I would enjoy being schooled on the practical (or other) differences.

Cheers

Zwiefel
03-08-2013, 03:45 AM
I'm not nearly as sophisticated as a lot of the folks here but....I love having stainless cladding and carbon core.

chinacats
03-08-2013, 03:57 AM
....I love having stainless cladding and carbon core.

Thanks, but no stainless for me (though I have owned a Carter as described); again, my interest is more in grasping the technical/performance differences.

Von blewitt
03-08-2013, 04:05 AM
San Mai is easier to thin, softer cladding is easier to abrade than hardened mono steel, but is more easily scratched. I've heard people say San Mai feels "muted" but I don't agree. I like the difference between jigane & hagane when polished on naturals. My preference is for San Mai

chinacats
03-08-2013, 04:12 AM
San Mai is easier to thin, softer cladding is easier to abrade than hardened mono steel, but is more easily scratched. I've heard people say San Mai feels "muted" but I don't agree. I like the difference between jigane & hagane when polished on naturals. My preference is for San Mai

Thanks, makes perfect sense (though it seems I wind up scratching all my blades, sometimes less from sharpening than just handling/use). Is that the only real difference and the main reason people would choose sanmai?

Cheers!

kalaeb
03-08-2013, 04:14 AM
I will be darned if I could tell a difference in cutting or sound in a blindfolded test.

cclin
03-08-2013, 05:17 AM
from my understanding, in general speaking, San Mai is upgrade from mono-steel knife(Honyaki is exception)in Japan cutlery! San-Mai construction needs more finishing processes & work to accomplished! the soft iron/stainless out layer add ductility to hard and brittle carbon steel(hagane); moreover, kept "Hagane" free of corrosion while maintaining strength and durability!! my vote goes to San-Mai.....:knife:

Matus
03-08-2013, 05:35 AM
As of now I have 3 knives with different SanMai blades. But I am still not clear about the toughness of the blade - my naive understanding is that the cladding is mostly not harden-able and so it does not add much to the toughness of the blade. I do understand that with some high hrc steels the caldding with softer steel may make the knife less susceptible to breaking.

In some cases cladding seems the way to actually save the costs as some cutting steels are quite expensive.

But I do have the impression that my Shun which has VG-10 core clad with stainless damascus is simply too weak (or easy to bend and and soft) - possibly because the core is too thin. The Yoshikane knives that I have just bought are much stronger (although slightly thicker).

So - I would also like to know what is there beyond look (love the look of the knives by Burt Foster), sharpening and (with carbon core) staining protection the advantage of SanMai.

cclin
03-08-2013, 05:46 AM
BTW, for stainless/PM steel I do prefer Mono-steel construction!! the San-Mai out-layer for stainless/PM steel blade mostly for Aesthetics look only!!

WillC
03-08-2013, 06:13 AM
For what its worth....from a Maker point of view.......

San mai is pretty and made in an interesting and more artful way than grinding a piece of mono steel, though that is artful too of course......... I tend to think the joy of creating something is reflected in the beauty of the object.

The Metallurgy becomes exciting visually and practically.
Using stainless clad and high carbon core, you will loose a percentage of carbon to the soft stainless cladding. You can either make the core a bit thicker so you have a certain amount as sacrificial carbon...Use a steel which could work well with slightly less carbon......Or add a layer of pure nickel to keep the carbon in the core. Of course that way you have a crisp weld line without the frosty hamon-esc effect. Either way you get something pretty special and unique.

Structurally, the blade does feel different. For example a soft clad san mai can be straightened with relative ease with hammer and stump with the core 62 hrc plus. Mono would demand far more care if you were working out a warp post heat treatment. This should tell you something about the feel and toughness of the blade. Though it will have relatively little effect in supporting the very edge it could help stop a huge chip in a very extreme situation. Though realistically this can all be optimized with good heat treatment in mono steel for our practical uses.

To me using different materials in a knife either in san mai or a composite construction is like having a differential heat treatment. You can have the spine or cladding softer than the the core or edge weld. And it might not be completely soft, I often use steels that temper differentially, looking for a core which is 60 plus while the cladding or spine is less than 58 hrc. Or medium carbon steel less than 55 hrc.
But these are not for use as swords granted where the extra toughness and flex would be a great advantage, so its largely a joy of the art in doing it thing. And the knowledge that you blade has an optimal construction.

Soft or softer clad knives are easier to grind and sharpen or at least thin, though also easier to mark the cladding in use.

You can use a combination of stainless clad and carbon core, thats probably one of the nicest advantages in practical use.

Umm and it look purty....did I mention that:D

Pensacola Tiger
03-08-2013, 06:41 AM
But I do have the impression that my Shun which has VG-10 core clad with stainless damascus is simply too weak (or easy to bend and and soft) - possibly because the core is too thin. The Yoshikane knives that I have just bought are much stronger (although slightly thicker).



Have you actually bent your Shun, or is this just an impression?

Matus
03-08-2013, 07:11 AM
Will, that is great information, thanks.


Have you actually bent your Shun, or is this just an impression?

Not much, but yes I did - when I was trying (with bare hands and I am no Hercules either) to see how strong it is. It did not take much effort to bend the knife AND not much of bending angle. It did not take much effort to straighten it back either. When I compare this blade to my 20 Euro Mora 2000 (19c27) - whose blade is barely thicker - it is worlds apart.

Later I had a very similar in size, shape and design (stainless core with stainless damascus cladding) knife from German producer in hand and it was even worse. And the knife was more than 100 euro (6" pairing blade).

panda
03-08-2013, 07:13 AM
i hate layered blades, no feedback, just a dead thunk. like driving a big slow automatic transmission mobile vs a porsche.

dough
03-08-2013, 07:19 AM
Umm and it look purty....did I mention that:D

i agree

http://www.fototime.com/CD1847C470A13E7/standard.jpg

one day burke you will be mine :)

and will that was a great post.

Von blewitt
03-08-2013, 07:32 AM
i hate layered blades, no feedback, just a dead thunk. like driving a big slow automatic transmission mobile vs a porsche.

I'm curious which San Mai knives you have used? I've personally not found this to be the case... But I guess everyone has there own opinion

franzb69
03-08-2013, 07:33 AM
now if it was san mai'd like that, high up, then the thickness wouldn't be much of a problem and probably even the "muted" qualities might get to be brought out again from thinning it that way.

http://www.fototime.com/CD1847C470A13E7/standard.jpg

Matus
03-08-2013, 07:46 AM
SanMai something along this line could be just fine ... not exactly a kitchen knife though :angel2:

http://www.burtfoster.com/images/hunter-050.jpg (http://www.burtfoster.com/hunters/hunter_50.htm)

(from Burt Foster)

franzb69
03-08-2013, 08:10 AM
SanMai something along this line could be just fine ... not exactly a kitchen knife though

reminds me of dave's work on thinned hiromoto AS sujis/gyuto.

also of another non-kitchen knife maker from another forum.... claudio of CAS

http://www.pbase.com/balisong/image/140758201/original.jpg

Chefdog
03-08-2013, 08:41 AM
I haven't used a ton of clad blades, but the ones I have used have been noticeably stiffer vs monosteel knives of comparable thickness. I haven't noticed a discernible difference in feel between the two, but I haven't really been looking for it. I like less flex in my blades, and I appreciate the ability of cladding to allow a slightly harder tempered cutting edge with less brittleness throughout the whole blade.

I appreciate that my new 300mm suji is pretty stiff due to the San Mai construction, but without having to be too thick to maintain the stiffness. But in the end, I really don't let mono vs San Mai have very much say in whether or not ill buy a knife because there are just too many other more meaningful factors to consider, IMHO.

Marko Tsourkan
03-08-2013, 10:27 AM
In terms of cutting performance, there should be no difference, however, a thinly ground sanmai knife could be bent and stay bent, while monosteel will flex back. For me it is a major factor choosing one over the other. On thicker knives like yanagi, deba and others, bending or warping is only an issue if heat treatment is not at its best, but those could be straightened (in most cases).

Canadian
03-08-2013, 12:11 PM
In terms of cutting performance, there should be no difference, however, a thinly ground sanmai knife could be bent and stay bent, while monosteel will flex back. For me it is a major factor choosing one over the other. On thicker knives like yanagi, deba and others, bending or warping is only an issue if heat treatment is not at its best, but those could be straightened (in most cases).

I agree. Moreover, anybody who attempts to claim that the technical performance of San Mai construction is better in terms of "durability" or "toughness" due to the softer core is full of crap considering the design function of a chef's knife.

chinacats
03-08-2013, 02:17 PM
Thanks for the responses folks, just the information I was looking to hear.

Cheers

Larrin
03-09-2013, 11:17 PM
O
I haven't used a ton of clad blades, but the ones I have used have been noticeably stiffer vs monosteel knives of comparable thickness. I haven't noticed a discernible difference in feel between the two, but I haven't really been looking for it. I like less flex in my blades...
There is no difference in stiffness between soft and hard steel.

sachem allison
03-10-2013, 12:19 AM
O
There is no difference in stiffness between soft and hard steel.

Larrin, would there be a difference in stiffness do to lamination? I know many laminated woods are stiffer than the original components on their own.

Chefdog
03-10-2013, 12:21 AM
I certainly won't argue your knowledge of the properties of steel. That's definitely a losing battle on my part.
But, I wasn't claiming that I notice a difference between harder and softer steel, if that's what you inferred from my statement. I was just saying that in my (limited) experience, the san mai blades I've used have seemed to have less flex than the monosteel knives I've used. Obviously, that's quite a small sample, and I guess probably says more about those particular knives than it does about the inherent differences in blade construction.
I'd certainly like to hear the scoop on this though. Are there any metallurgical factors at play concerning the stiffness between mono/clad blades, or is it just down to the properties of individual knives?

EdipisReks
03-10-2013, 12:37 AM
O
There is no difference in stiffness between soft and hard steel.

well, that would really depend on how soft the steel is, right? i'd say half an ounce of steel living in a big jar of aqua regia is going to be pretty soft, and pretty non-stiff ;)

the san-mai knives i've used have tended to be quite stiff, which i like, but i'd say that they are stiff because they tend to have thicker spines than monosteel knives. i love san-mai knives like Heiji, Shig (and the good) Takedas. i hope to try a DT san-mai,some day.

PierreRodrigue
03-10-2013, 12:43 AM
The examples of san mai I have made, have no "softer" layer. I construct mine using all hardenable steels. O1, 1084, 15N20. If the bend, and if they take that bend, I screwed up big time!

chinacats
03-10-2013, 12:54 AM
The examples of san mai I have made, have no "softer" layer. I construct mine using all hardenable steels. O1, 1084, 15N20. If the bend, and if they take that bend, I screwed up big time!

So can I infer that when you temper that you are hardening/treating the whole blade and likely the hardness while not the same, is probably proportional? I can honestly say that any blade that I have bent back has snapped right back into place like I would think it should, this includes san mai as well as monosteel.

EdipisReks
03-10-2013, 01:02 AM
The examples of san mai I have made, have no "softer" layer. I construct mine using all hardenable steels. O1, 1084, 15N20. If the bend, and if they take that bend, I screwed up big time!

My Takedas will bend, if made to, but I've never seen any other clad knives, and I've owned and used dozens, have any bendy characteristics, so I'd say you are doing it right!

mpukas
03-10-2013, 01:12 AM
Hoss made a post quite a while back saying that san mai blades are stiffer due to the tension created between the different steels when forge welded. Hoss - correct me if I'm wrong.

PierreRodrigue
03-10-2013, 01:19 AM
So can I infer that when you temper that you are hardening/treating the whole blade and likely the hardness while not the same, is probably proportional? I can honestly say that any blade that I have bent back has snapped right back into place like I would think it should, this includes san mai as well as monosteel.

My entire blade is heat treated to HRC 61-62. It MAY vary by a half point between steels. The reason they work well together, is because they essentially have the same HT process/recipe.

Don Nguyen
03-10-2013, 01:21 AM
well, that would really depend on how soft the steel is, right? i'd say half an ounce of steel living in a big jar of aqua regia is going to be pretty soft, and pretty non-stiff ;)

From what I know, the elastic modulus for steel in general is about the same, regardless of hardness. Thus, the 'stiffness' of a knife primarily depends on cross sectional thickness/geometry.

Marko Tsourkan
03-10-2013, 01:23 AM
It's much simpler than you guys think. Japanese use low carbon cladding, which doesn't harden. Some clad with stainless steel over carbon. Stainless cladding will only marginally harden (low RCs), as stainless steel is heat treated at higher temperature than carbon. If you use comparable carbon steels, like Pierre, that are heat treated at similar temperatures, you should get more or less uniform hardness of core and cladding.

keithsaltydog
03-10-2013, 01:35 AM
Some of those San Mai blades have an asthetic appeal.For workhorse blades in production Kit. esp. under 200.00 range there are solid values in mono-steel knives like Gesshen Uraku,Suisin Inox,Kanetsugu Pro M,Carbonext,& mono carbons in White or Blue.

Damascus costs more,looks good,but does not make a knife cut better.Sharpening is diff. too,when I sharpen Shuns,rinse the mud off the stone often,because it can scuff the shiney dimpled Damascus at low angle thinning.

My Carbon Masamoto petty walked at work,replaced wt. a Hiromoto AS,worked fine as a petty,only San Mai knife I have used alot.

Esp. wt carbon cores I would guess that the more expensive San Mai with good blade geometry,not only look good but are solid cutters as well.

EdipisReks
03-10-2013, 02:40 AM
From what I know, the elastic modulus for steel in general is about the same, regardless of hardness. Thus, the 'stiffness' of a knife primarily depends on cross sectional thickness/geometry.

it was a joke, aqua regia being something that dissolves steel, so steel dissolved in liquid would be pretty soft and pretty non-stiff, being liquid.

cclin
03-10-2013, 03:49 AM
......Damascus costs more,looks good,but does not make a knife cut better.Sharpening is di......
not all ture!! from my basic knowledge of The Metallurgy, there are many different the diverse techniques all call "Damascus"!!
*Folding Damascus(kitaji or layered-steel)- Folding one or multiple-layered jigane(high-carbon steel) several times, gives many layers with irregular Damascus patterns; this kind of Damascus that have longer kirenaga(better edge retention)
*laminating Damascus(Shun, miyabi..etc)- just a core of hard steel in the middle; Damascus patterns stainless clad surrounded. mostly for Aesthetics look only!
*pattern welding Damascus- The loose stack of steel is banged into a rod with a cross section Next, these rods are twisted and ground flat on two sides.
*"True" Damascus(wootz steel)
all above are just my basic knowledge about Damascus. here on KKF have many members with more knowledge of The Metallurgy than me, please correct me if I'm wrong & educate me more!!:)

keithsaltydog
03-10-2013, 06:14 AM
OOps yes true Damascus can make a sword more flexible & harder,stronger.traces of carbon form visible patterns and swirls in the layered steel.

Damascus is common in kitchen and hunting knives,a vast majority laminated wt lighter & darker steels,also folding wire,it makes pretty knives,is more work to produce so can be very expensive,but these do not give better Kirenaga.That's what I think anyway,don't see how a surfice San Mai Damascus can make a knife cut better,JMO

A mono steel Honyaki blade forged wt. clay to form a true Hamon line can have great edge holding,I love the look of a true Hamon on swords & knives.Functional & stunning to look at.

cclin
03-10-2013, 07:36 AM
Damascus is common in kitchen and hunting knives,a vast majority laminated wt lighter & darker steels,also folding wire,it makes pretty knives,is more work to produce so can be very expensive,but these do not give better Kirenaga.That's what I think anyway,don't see how a surfice San Mai Damascus can make a knife cut better
Folding Damascus(kitaji/layered-steel) do have longer kirenaga(better edge retention) than kasumi blade!!
San Mai Damascus(laminating Damascus) don't!!

Marko Tsourkan
03-10-2013, 10:14 AM
A mono steel Honyaki blade forged wt. clay to form a true Hamon line can have great edge holding,I love the look of a true Hamon on swords & knives.Functional & stunning to look at.

There will be no more edge holding on a honyaki than on a same core steel in san mai blade if heat treated the same way. Hamon is a side-product of a necessary production step - keeping back soft so you can straighten the blade after it is heat treated. It's very difficult to keep the blade from warping when quenched in water. That's the main reason honyaki is priced and is expensive - the difficulty of production and high rate of failure.

Some makers over-harden their honyaki knives to get more wear resistance from simple carbon steels, but the downside of it is the brittleness. Your priced possession might break in half if you drop it on a tiled floor.

You might get impression that there is more wear resistance while sharpening a single bevel honyaki. In this case you are removing hardened steel from the whole bevel, while in san mai just from the core.
M

NO ChoP!
03-10-2013, 10:51 AM
+1 to the bendable Takeda. I've seen them bend like cheap cafeteria forks!

Marko Tsourkan
03-10-2013, 12:55 PM
Not just Takeda. All thinly ground san mai (including Carters) will bend in your fingers if you apply enough pressure. If you don't believe me, try it at your own risk. Thicker san mai blades will bend too, but you will need to apply more force.

What will not bend is when cladding is comparable to core steel. Devin AEB-L san mai is essentially AEB-L throughout, same hardness after heat treating.

Don Nguyen
03-10-2013, 12:57 PM
it was a joke, aqua regia being something that dissolves steel, so steel dissolved in liquid would be pretty soft and pretty non-stiff, being liquid.

Oh... well that went right over my head...

:)

keithsaltydog
03-10-2013, 05:42 PM
Folding Damascus(kitaji/layered-steel) do have longer kirenaga(better edge retention) than kasumi blade!!
San Mai Damascus(laminating Damascus) don't!!

Yes agree,and most all of Damascus in Kitichen knives is surface decoration,there are custom forgers folding many layers of carbon steel,but it is a small %.

I am not knocking Damascus,some of these knives look great,esp. wt. custom exiotic wood handles.All I am saying is there are better deals out there in mono steels both Quality Stain Resistant & Carbons for production Kitchens.:)

Larrin
03-10-2013, 06:44 PM
I certainly won't argue your knowledge of the properties of steel. That's definitely a losing battle on my part.
But, I wasn't claiming that I notice a difference between harder and softer steel, if that's what you inferred from my statement. I was just saying that in my (limited) experience, the san mai blades I've used have seemed to have less flex than the monosteel knives I've used. Obviously, that's quite a small sample, and I guess probably says more about those particular knives than it does about the inherent differences in blade construction.
I'd certainly like to hear the scoop on this though. Are there any metallurgical factors at play concerning the stiffness between mono/clad blades, or is it just down to the properties of individual knives?
Any difference from flex would be from thickness and geometry. The only complicating factor would be tension from the steels having different size changes post heat treatment. However, that still wouldn't decrease stiffness. Stiffness is controlled by the Elastic modulus which is unaffected by heat treatment. It's controlled by the strength of the bond between atoms. Therefore any change would have to be from alloying or from being a different phase (i.e. Austenite). However, even highly alloyed, austenitic stainless steel has essentially the same elastic modulus. The difference in properties between soft and hard steel comes at yielding. Softer steels have a lower yield point, or in other words, they require less bending to stay bent.

Chefdog
03-10-2013, 07:15 PM
Any difference from flex would be from thickness and geometry. The only complicating factor would be tension from the steels having different size changes post heat treatment. However, that still wouldn't decrease stiffness. Stiffness is controlled by the Elastic modulus which is unaffected by heat treatment. It's controlled by the strength of the bond between atoms. Therefore any change would have to be from alloying or from being a different phase (i.e. Austenite). However, even highly alloyed, austenitic stainless steel has essentially the same elastic modulus. The difference in properties between soft and hard steel comes at yielding. Softer steels have a lower yield point, or in other words, they require less bending to stay bent.

Larrin,
Thanks, I think :what:
If I understand correctly (which is a big assumption), what that means to the layman is:
The differences are just due to the variances between knives, nothin more.

Thank you. Even if I have to read them several times, I always enjoy and learn from deciphering your posts.

keithsaltydog
03-10-2013, 09:43 PM
Not just Takeda. All thinly ground san mai (including Carters) will bend in your fingers if you apply enough pressure. If you don't believe me, try it at your own risk. Thicker san mai blades will bend too, but you will need to apply more force.

What will not bend is when cladding is comparable to core steel. Devin AEB-L san mai is essentially AEB-L throughout, same hardness after heat treating.

Mark what is the advantage of making a San Mai blade out of the same steel eg. AEB-L?Is it Functional or Asthetic or both?

Von blewitt
03-10-2013, 09:50 PM
Mark what is the advantage of making a San Mai blade out of the same steel eg. AEB-L?Is it Functional or Asthetic or both?
I think he's talking about AEB-L Damascus clad AEB-L. so aesthetics is the goal