# mono v clad; ground v forged



## mpukas (Nov 8, 2011)

Here's a topic that gets touched on briefly and often mentioned randomly in posts, but never have I seen a full-blown thread dedicated to it. 

Do you prefer a mono steel knife or a clad/san-mai knife? 

Is there a benefit of forged v ground? 

It appears to me that mono steel knives are most often ground from solid stock, as in the case of {most if not all} lasers (although not always - they may be forged), and clad knives are most often forged (although not always - they may be ground from pre-made stock). 

I can see both styles (if you will) have pros and cons, and I'm not sure I have strong preference. I do like a thin knife however, and often clad knives tend to be on the thicker side. 

On the topic - here's a question - in the case of a mono steel laser that is ground, where in the process of fabrication is the heat treatment done? Once the knife has been cut and ground to shape, but before final finish, edge and handle attachment? Cheers! mpp


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## Eamon Burke (Nov 8, 2011)

The less grinding that is done before Heat Treat, the better. The thinner it is, the more likely it is to warp in the oven, so you suck it up and grind the hardened stuff, or get used to bent blades.


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## ajhuff (Nov 8, 2011)

I have not handled enough knives to feel a difference. I don't see a point in clad knives. To me it is an archaic technology held over from sword making that serves no true purpose in kitchen knives. I also have yet to be convinced that a forged to shape knife is not superior to a cut and ground knife, but I base that on theory not personal experience.

-AJ


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## tk59 (Nov 8, 2011)

Pretty much, it's personal preference although stainless clad, carbon steel reduces the reactive surface. Some steels are difficult to finish so shiny cladding help aesthetically, as well. Some of my best performers are cladded but I don't thing the cladding has anything to do with it. It does prevent you from being able to mod in every way you might want.


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## Lefty (Nov 8, 2011)

There's a time and place for both mono and San Mai. My 4 favourite knives I've used to date are 2 mono, 2 clad and 2 forged, 2 "cut out". All of them cut compareably, and have different feels. Right now I'm using a KU (clad) knife for everything, but when I get my pettysuki back from Rick (thanks for keeping it in shape, by the way and please keep enjoying it) I'm sure it'll be number one, splitting time with the Carter suji. Again, 1 mono, 1 clad, one from stock, the other forged.
I think it's more about what you like and what makes you happy when you use it. I will, however agree with TK, when he says that a stainless clad carbon core knife greatly reduces reactivity, etc.


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## Mike Davis (Nov 8, 2011)

Forged vs. ground. 
There are advantages to both here. Forging allows you to forge essentially to shape, reducing the time spent on the saw and grinder. Also you can do thermal cycling when forging to get the grain size reduced and the stresses relieved. Suitable for the simple carbon steels and tool steels.
Stock removal allows you the option to explore the world of Stainless and CPM steels(Crucible Powdered Metallurgy) which start with insanely fine grain steel and better stain resistance. The problems with stainless steels, there are few that are suited for kitchen knives, and you cannot forge them...most anyway. To me, cladding is mostly an aesthetic option, But one that allows damascus cladding. One thing about cladding is making sure the welds are solid through out...Issues that do not arise with mono steels.

Basically, i feel that it is a preference to the user, personally i like the more intimate aspect of forged blades....


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## tk59 (Nov 8, 2011)

Mike Davis said:


> ...Also you can do thermal cycling when forging to get the grain size reduced and the stresses relieved...CPM steels(Crucible Powdered Metallurgy) which start with insanely fine grain steel...


How much can the grain size be reduced? Where are you getting the idea that the grain size on PM steels (Crucible or otherwise) are insanely fine-grained? I was under the impression they aren't that fine.


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## l r harner (Nov 8, 2011)

depending on the powder used the steel vcan and will be verry fine grained. std smelt can have alloy boandign in them that makes for funn drilling or grinding (also in HT )
\
tho if you are talking abot the finest grain std smelt steel vz the finest PM steel it will be close as the PM steels are used more for higer alloys not the finer grain simple steels (when have youb ever heard of PM 1095 ) 

there are super pure allys liek B52 out there but pure and fine grain can somtimes mean different things


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## Eamon Burke (Nov 8, 2011)

PM1095 :laughat:


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## tk59 (Nov 8, 2011)

l r harner said:


> depending on the powder used the steel vcan and will be verry fine grained. std smelt can have alloy boandign in them that makes for funn drilling or grinding (also in HT )
> \
> tho if you are talking abot the finest grain std smelt steel vz the finest PM steel it will be close as the PM steels are used more for higer alloys not the finer grain simple steels (when have youb ever heard of PM 1095 )
> 
> there are super pure allys liek B52 out there but pure and fine grain can somtimes mean different things


Yes. PM steels are generally around to reduce the size of the huge grains obtained from high alloy steels. As far as I know, they don't get close to that of simple steels.


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## Vertigo (Nov 8, 2011)

This is gonna sound like hippie mumbo-jumbo, so at the risk of completely embarrassing myself I'm gonna say that to me, clad knives feel a bit flatter in use--that there's less tactile feedback to the cuts than with a comparable mono-steel knife. It's not a deal breaker, and Carter's clad knives are dreamy... but I'd just rather have the same knife _without_ the stupid cladding gumming things up. 

And no, I haven't been smoking dope.


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## Mike Davis (Nov 9, 2011)

This is mainly for forged steel. Its not ALL about grain refinement. Once a steel reaches critical temperature, the carbide matrix goes into solution and grain growth starts to happen. By starting at just below critical(1414 in simple carbon) and reducing the heat each time you normalize the steel, you are actually putting the carbide solution into a microstructure that is less stressed and reducing the grains. After the last normalizing heat(usually 3) you can quench and essentially lock in the grain size and structure. After that, bring back to above critical for the amount of time you need(varies depending on the steel), and quench your final quench. Now what you have done is reduced the stress on the steel and got the grain size refined back down again...Now you start with smaller grains than you would after forging, to start your final heat for final quench. Simple carbon steels can have huge grains....We have no control over what the steel mill does as they are producing the steels....Some hot rolled stock is damn near impossible to drill through in the state you get it in, ie: flat stock....It is generally poured somewhere around the 33-3600 degree range, ran through the mill and hot formed...then left to cool which can introduce a small measure of air/work hardening.


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## Sarge (Nov 9, 2011)

Vertigo said:


> This is gonna sound like hippie mumbo-jumbo, so at the risk of completely embarrassing myself I'm gonna say that to me, clad knives feel a bit flatter in use--that there's less tactile feedback to the cuts than with a comparable mono-steel knife. It's not a deal breaker, and Carter's clad knives are dreamy... but I'd just rather have the same knife _without_ the stupid cladding gumming things up.
> 
> And no, I haven't been smoking dope.


 
I find this as well, someone once compared it to using a condom. For this reason I prefer monosteel knives. Better feed back when cutting, I can sharpen it to very extreme asymmetry without having to constantly work on moving back the cladding. All around I'd just prefer a mono-steel knife. 

All that being said I do love my Moritaka; however when his life ends he's being replaced with a mono-steel knife. Most likely a Yoshihiro from Jon, or maybe I'll finally go laser.


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## Citizen Snips (Nov 9, 2011)

i have turned the page on clad knives. i used to be a big fan and believer but recently i feel as though they have characteristics that dont fit my bill anymore.


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## Iceman91 (Nov 9, 2011)

I have had quite a few monosteel knives, and recently purchased my first clad knife (Carter). As far as working in a kitchen, for me, clad is the way to go. When i am super busy and dont have the time to wipe off my monosteel knives with every use, i was getting tiny rust spots on them. That's after i already had a patina on them. With my clad i never have to worry about it. I haven't noticed any difference in feel or performance with clad either.

Mike


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## Cadillac J (Nov 9, 2011)

I prefer mono-steel all the way, but not because of anything related to forging or grind.

Cladded knives have a muted or dulled feeling when makings cuts to me...less feedback and don't feel as good.

kcma had the best analogy when he said "clad knives are like wearing condom"


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## WillC (Nov 9, 2011)

I'm surprised no one has mentioned it, but when you like your steel as hard as 61/62hrc as I think many here do, the cladding acts to toughen up the blade and support the edge, (depending on how close to the edge it comes). I'm moving towards using different carbon steels, (not mild) in place of a differentially hardened/or tempered blade. This is done with sword constructions allot, and gives you a safety measure against receiving a blade back in several pieces, if extreme edge hardness is required.


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## Larrin (Nov 9, 2011)

Does damping really occur with properly laminated blades? I'm still not sure. A difference would arise from disparity in elastic modulus between composite materials, which shouldn't be much different between two steels. Are people using poorly laminated blades or is it just a placebo effect? The difference in vibration could also be observed through sound (also vibration). Anyone tried ringing their blades to listen for differences?


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## mpukas (Nov 9, 2011)

I definitely notice a muted feeling on my clad blades, both in terms of cutting feedback and sound when sharpening (not that the later matters at all). The heavier the knife, the more muted. My Moritaka 270 kiri-gyuto is like a big sharp club. The Blazen is a nice compromise between being super-sturdy but not clunky and light and nimble with good feedback. No fear of bending the blade by smacking garlic w/ the side. But I grab the laser 98% of the time; I'll use one of my other knives occasionally just for comparison, and always come around to preferring the mono laser. 

I've not found a mono steel knife, outside of a honyaki, that is harder than 61-62. Seems to me if you want to go higher/harder than that you're looking at a clad blade, like JKI's Heiji line (again discounting a honyaki).


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## WillC (Nov 9, 2011)

It certainly not a placebo effect, it can be a genuine tool. If your core material reaches say 62hrc at a given temper temperature and your cladding is at a relatively tough springy 55 hrc. I'd say thats a very good thing in overall blade strength. I'm not convinced how much it would support the edge, it would have to be really close to do anything to prevent small chips
Not that your going into battle with a kitchen knife or anything but accidents can happen. If you look at some Seax and sword constructions, they used up to 3 or 4 different types of steel to achieve a differential hardness, soft on the spine, medium in the middle and high carbon edge. Granted they did not have the benefit of modern steels but I believe used right it can be a genuine tool. I'm sure some are intended more for "the look" than anything else.


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## tk59 (Nov 9, 2011)

Cadillac J said:


> ...kcma had the best analogy when he said "clad knives are like wearing condom"


I guess a lot of the finest sushi chefs in the world are missing out, aren't they? I hope kc can help them.


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## Vertigo (Nov 9, 2011)

Larrin said:


> Does damping really occur with properly laminated blades? I'm still not sure. A difference would arise from disparity in elastic modulus between composite materials, which shouldn't be much different between two steels. Are people using poorly laminated blades or is it just a placebo effect? The difference in vibration could also be observed through sound (also vibration). Anyone tried ringing their blades to listen for differences?


 I notice degrees of difference based off the quality of the cladding, sure. The Hiro AS I used felt like a wet burlap sack, whereas the aforementioned Carters felt much more visceral and responsive. That could also be a byproduct of their hugely disparate thicknesses. Either way, it's nothing I've spent a lot of time contemplating, just a few casual observations that steered my general purchasing preference.


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## JohnnyChance (Nov 9, 2011)

I'm fine with either, have both and enjoy both.


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## oivind_dahle (Nov 9, 2011)

The more I play with knives, the more I love sanmai

* Protects the brittle core steel 
* creates non-reactive surface to knife

What Ive heard is that
* the core steel is more expencive and harder to finish.

I really like my Carter sanmai, however Im having really high expectations to my next sanmai....


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## Larrin (Nov 9, 2011)

raisedbybrocks said:


> It certainly not a placebo effect, it can be a genuine tool. If your core material reaches say 62hrc at a given temper temperature and your cladding is at a relatively tough springy 55 hrc. I'd say thats a very good thing in overall blade strength. I'm not convinced how much it would support the edge, it would have to be really close to do anything to prevent small chips
> Not that your going into battle with a kitchen knife or anything but accidents can happen. If you look at some Seax and sword constructions, they used up to 3 or 4 different types of steel to achieve a differential hardness, soft on the spine, medium in the middle and high carbon edge. Granted they did not have the benefit of modern steels but I believe used right it can be a genuine tool. I'm sure some are intended more for "the look" than anything else.


I'm aware of the difference in hardness, I'm saying damping would occur through elastic modulus differences which are unaffected by hardness. I think the whole debate over a "dead" feeling are from poorly laminated blades. A properly laminated blade should have no such difference.


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## WillC (Nov 9, 2011)

Elastic modulus differences. mmmm I won't pretend to know what that is, but imho, a good weld is a good weld, i've never noticed any loss of feel to a blade in san mai. Having said that the layers in san mai are less consolidated than in damascus so extra care must be taken that the weld is good, any flaw will show up on grinding, after HT if not before however. I suspect there would have to be de-lamination to effect the feel of the blade.


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## Cadillac J (Nov 9, 2011)

tk59 said:


> I guess a lot of the finest sushi chefs in the world are missing out, aren't they? I hope kc can help them.


 
Talking about double beveled knives only, this doesn't apply for yanagis or other single bevels.


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## Larrin (Nov 9, 2011)

Cadillac J said:


> Talking about double beveled knives only, this doesn't apply for yanagis or other single bevels.


 Why?


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## Sarge (Nov 9, 2011)

Based on my limited experience the way the cladding is on a kasumi knife(mostly on one side only) and the very thin edge provide more feed back than sandwich construction. Can't say why but there is far more feedback from my Kiritsuke than from the Moritaka Kiri-gyuto


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## Justin0505 (Nov 9, 2011)

I've done a bit of reading about elastic modulus recently (thanks to Larrin), and it also still blows my mind that it's not effected by HT. However, different steels do have different elastic properties... So it doesnt shock me that a blade made of a composite of steels "A" and "B" would have different harmonics and transmit vibration differently than one made of just steel "A".

However, it also seems obvious that factors like thickness, grind, balance point, handle construction and material would all be significant attributing factors to what often gets attributed just to blade construction. Until
Someone makes some knifes that are identical in every way but blade construction, this is going to be just another matter of personal opinion and taste. -but I guess that's really all that matter in the end.


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## Larrin (Nov 9, 2011)

Justin0505 said:


> I've done a bit of reading about elastic modulus recently (thanks to Larrin), and it also still blows my mind that it's not effected by HT. However, different steels do have different elastic properties... So it doesnt shock me that a blade made of a composite of steels "A" and "B" would have different harmonics and transmit vibration differently than one made of just steel "A".
> 
> However, it also seems obvious that factors like thickness, grind, balance point, handle construction and material would all be significant attributing factors to what often gets attributed just to blade construction. Until
> Someone makes some knifes that are identical in every way but blade construction, this is going to be just another matter of personal opinion and taste. -but I guess that's really all that matter in the end.


Differences of elastic modulus between different steels is pretty small, I don't think it would be perceptible. That's what I would like to know: if there is a real difference, and if there is a real difference is it because of poor lamination.

Edit: When I say a real difference I don't mean between young's modulus of the different steels I mean between clad and not. This whole idea of the "condom" thing came from one or two people and spread like wildfire and I'm still skeptical about the whole thing.


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## WillC (Nov 9, 2011)

Have you got a link to your bit about elastic modulus differences please Larrin?


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## Larrin (Nov 9, 2011)

raisedbybrocks said:


> Have you got a link to your bit about elastic modulus differences please Larrin?


http://www.engineeringtoolbox.com/young-modulus-d_773.html


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## StephanFowler (Nov 9, 2011)

one thought to consider is that the slightest flaw in the weld with San-Mai will act as a harmonic dampener.

a good way to check a bar of damascus for solid welds is to hold it lightly 1/3 from the end and lightly "ring" the end of the bar with a hammer. It should produce a clear bell like tone with no rattle and a good bit of sustain.

if it's a dull thunk or the ring pans out quickly then there is a bad weld in the bar somewhere.

the same concept would apply to San-Mai construction


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## mpukas (Nov 9, 2011)

Larrin said:


> ...I don't think it would be perceptible...


 
Not debating/doubting your theory on modulus, but have you compared cutting with a laser and a clad gyuto side by side? I have, as have others. I certainly notice a big difference in tactile feel and prefer the feel of a mono laser for most tasks. 

I don't know that much about steel and knife construction, but in the vids I've watched of san-mai blade construction, it's very different than damascus forging. From what I've seen (by Carter and Moritaka) a soft piece of metal is heated, shaped a bit into a block; and then a harder piece of edge steel is basically hammered into to the red-hot cladding block. From there it's pounded into shape. I can see how this technique will result in a less feedback due to the amount of (presumably) softer, cheaper steel, Saying that, I think the quality of the cladding will have an impact on tactile feel. 

Two other points to address; 

reactivity - this is dependent on the cladding metal; I've found the cladding can be more reactive than the edge unless it's some SS variation. 
durability - cladding, to me, does nothing to protect the edge; it can protect the entire blade from breaking due to being dropped, but it won't protect the edge from chipping. 

I've seen Carter say he likes clad clad blades because they are stronger (meaning the softer cladding will protect the core steel from shattering) and easier to sharpen over time due to the cladding being easier to thin as the edge gets worn down.


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## Cadillac J (Nov 9, 2011)

Larrin said:


> Why?


 
Because the feel issue isn't as apparent with single bevels so I've heard(I don't use them), and to get a monosteel single bevel knife you are usually, if not always, talking a relatively expensive honyaki.

I can for sure feel a difference between all the cladded/non blades I've owned when making cuts, and I just prefer non-cladded overall. In no way am I saying that cladded blades are inferior...just not my cup of tea if I have the choice.


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## mpukas (Nov 9, 2011)

[video=youtube;UapXrxQxevY]http://www.youtube.com/watch?v=UapXrxQxevY&feature=related[/video] 

I'm not seeing any welds, or am I missing something? What is the powder put in the groove before the AS bar is placed in it?


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## WillC (Nov 9, 2011)

Borax, to act as flux, in this case as he has not cleaned the scale out from the slotted cladding it will help dissolve the scale too. I'm surprised he put two core pieces in. I suspect he was just forging the first piece down further into the cladding rather than welding, refluxed added the second, the next heat would have been the weld heat. Hard to guage heats from a video.


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## mpukas (Nov 9, 2011)

raisedbybrocks said:


> I'm surprised he put two core pieces in.


 
Are you sure you watched that correctly? He's doing more than 1 blank; 1 core peice per blank. 

Thanks for the info on the flux - that's what I suspected.


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## WillC (Nov 9, 2011)

Ha ha, yes your quite right, its getting late here. borax allows you to make the weld at a lower heat as well. But yeah, he hadn't made the welds yet then by the look of it, just seating the core.


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## Larrin (Nov 9, 2011)

mpukas said:


> Not debating/doubting your theory on modulus, but have you compared cutting with a laser and a clad gyuto side by side? I have, as have others. I certainly notice a big difference in tactile feel and prefer the feel of a mono laser for most tasks.
> 
> I don't know that much about steel and knife construction, but in the vids I've watched of san-mai blade construction, it's very different than damascus forging. From what I've seen (by Carter and Moritaka) a soft piece of metal is heated, shaped a bit into a block; and then a harder piece of edge steel is basically hammered into to the red-hot cladding block. From there it's pounded into shape. I can see how this technique will result in a less feedback due to the amount of (presumably) softer, cheaper steel, Saying that, I think the quality of the cladding will have an impact on tactile feel.
> 
> ...


I can't tell the difference between clad and not. 

I'm aware of the forging methods of making clad knives. I addressed the differences in hardness earlier in the thread. 

Reactivity, durability, and ease of sharpening are of course reasons to use san-mai, but I assume you're not bringing them up in regards to damping.


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## Larrin (Nov 9, 2011)

StephanFowler said:


> one thought to consider is that the slightest flaw in the weld with San-Mai will act as a harmonic dampener.
> 
> a good way to check a bar of damascus for solid welds is to hold it lightly 1/3 from the end and lightly "ring" the end of the bar with a hammer. It should produce a clear bell like tone with no rattle and a good bit of sustain.
> 
> ...


That's what I suggested earlier in the thread that I should have emphasized more. I'm interested in whether the blades that some have perceived differences in them have perceivable faults in the welding.


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## slowtyper (Nov 9, 2011)

My head, down here. This thread, up there.


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## MWhtrader (Nov 9, 2011)

I have read some literature on the perception of feel, and its mostly comprised of sound and touch. In the golfing world, forged clubs from 1018 steel are regarded to have the best feel, while stainless steels or multimaterial construction are usually described as feeling harsh or disconnected. Also, Mizuno golf uses harmonics (sound) to fine tune the feel of the clubs, where its usually accepted that sound in golf matters more to feel than forge or cast. 

Good thing here is that the knife is a simple geometry, which is a quasi cantilever beam, so I am going to approximate with the simple equations. we would be talking about resonance, which is most affected by length and spring constant(or elasticity modulus ). While I might be stretching a bit, but usually the cladding is shorter than the core, so that would recreate a difference in resonance, difference tend to decrease the overall quality of sound created. 

in the vibrations and dampening side, austenitic, ferritic, and martensitic steels all have different dampening coefficients. The differences in dampening coefficients will all affect vibration transmission and propagation. Not to mention the boundaries between the cladding and core steel will act as natural dampening. stainless steels will exhibit better damping due to magneto-mechanical effects according to Lazan,B.J. & Goodman,L.E., "Effect of Material and Slip Damping on Resonance Behavior", 1956, ASME, Shock and Vibration Instrumentation, pp.55-74. 

unfortunately, dampening is one of those black holes in engineering and its really tough to find reliable data, so take what i just said with a few lbs of salt, i may or may not be right. 

in short, I am fairly certain that mono steel knifes will "feel" better than clad, but its more about the ability of the user to discern the differences in feel.


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## JohnnyChance (Nov 9, 2011)

mpukas said:


> Not debating/doubting your theory on modulus, but have you compared cutting with a laser and a clad gyuto side by side? I have, as have others. I certainly notice a big difference in tactile feel and prefer the feel of a mono laser for most tasks.



Why does laser keep being using a synonym for mono steel blade in this thread? I have and used fat mono steel blades; and have and used very thin clad blades.

Maybe you just prefer the cutting feel of a thin knife? There are plenty of thin clad knives out there; Carter, Devin, Shigefusa (some), Kochi, etc. I'll take any of those over a wippy little mono blade from Sakai city.


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## Sarge (Nov 9, 2011)

A question for those who do feel a difference and those who don't. What type of cuts do you make the most? Do you pre-dominately push cut? Or do you mostly rock chop? Or some other type. I exclusively push cut, with either a forward or slightly backward motion depending on the food, (I haven't rock chopped in years).

The point I'm getting at is push cutting the difference in feel and feedback is very obvious (at least to me) now having stopped rock chopping before I picked up a cladded knife. I haven't tested this to see if it makes a difference in feeling, and I don't care enough to conduct one. Any-dang-way perhaps the difference in technique is the reason some feel and notice the difference where others do not? 

I'm guessing that for rock chopping the difference is less obvious but I could be very wrong


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## tk59 (Nov 10, 2011)

Tell you what. I have a bunch gyutos, several of which are stainless clad, some lasers in each category. I'll see if I can find a couple of pros that are willing to dice an onion with each, blindfolded and see if they can guess which are cladded. My money is on no one discerning a difference. I find the most important factors in feel is the weight of the knife and the sharpening job.


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## WillC (Nov 10, 2011)

That brings the term "harmonics" nicely into my sphere of understanding. Hit it with a hammer , excellent tip, people have told me dodgy anvils don't ring, makes sense with the older ones where the face is welded onto a wrought body.



StephanFowler said:


> one thought to consider is that the slightest flaw in the weld with San-Mai will act as a harmonic dampener.
> 
> a good way to check a bar of damascus for solid welds is to hold it lightly 1/3 from the end and lightly "ring" the end of the bar with a hammer. It should produce a clear bell like tone with no rattle and a good bit of sustain.
> 
> ...


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## JohnnyChance (Nov 10, 2011)

tk59 said:


> Tell you what. I have a bunch gyutos, several of which are stainless clad, some lasers in each category. I'll see if I can find a couple of pros that are willing to dice an onion with each, blindfolded and see if they can guess which is cladded. My money is on no one discerning a difference. I find the most important factors in feel is the weight of the knife and the sharpening job.


 
Good idea. There are too many variables in addition to blade construction. Most san mai blades use a core that is not offered in monosteel blades. And if they are, they are from different manufacturers. Different handle construction, different methods of attaching handles, materials in the handle and blade, grind/geometry/thickness would all affect feedback (and maybe more so) than mono v. clad.


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## mpukas (Nov 10, 2011)

JohnnyChance said:


> Why does laser keep being using a synonym for mono steel blade in this thread? I have and used fat mono steel blades; and have and used very thin clad blades.
> 
> Maybe you just prefer the cutting feel of a thin knife? There are plenty of thin clad knives out there; Carter, Devin, Shigefusa (some), Kochi, etc. I'll take any of those over a wippy little mono blade from Sakai city.


 
You're right - I wasn't intended to use laser as synonomous for mono. I do prefer the feel of cutting w/ a thin knife. I'd really like to try a thin clad knife, because I also like the sturdiness and heft of a clad blade. Trying to find the sweet spot.


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## Lucretia (Nov 10, 2011)

For simplicity's sake, let's treat the blade as a cantilever beam, and assume cladding is perfectly welded. 

The natural (resonant) frequency of a cantilever beam is going to be affected by the steel used (modulus of elasticity and density) and the geometry of the blade (thickness, height, length). The natural frequency will be proportional to:

the square root of 
(
( (Modulus of Elasticity) x (Thickness of blade) x (Height of blade CUBED) ) 

divided by 

( (Mass) x (Length of blade CUBED) )
)


The modulus of elasticity doesn't vary that much between steels, regardless of heat treat. Say in the range of 10%, which only will affect the natural frequency by about 5%. Mass also doesn't vary much with different steels, and is also a linear component of the equation.

Changes in height and length have more drastic effects because they are multiplied on top of themselves. Change the height or length of the blade by 10%, and your natural frequency is going to change on the order of 13-15%.

Since blades are thin relative to their height and length, a "small" change can actually be a fairly large change on a percentage basis. Go from a 1 mm blade to a 2 mm blade, and you've increased your resonant frequency by around 40%.

While there may be some damping due to material differences, geometry has a more significant effect on the dynamic response of the blade. Unless you're comparing blades that are exactly the same, you're looking at apples and oranges.

That said, if you don't have good physical connection between your layers, you've built a low-pass filter. If I remember correctly, a good bolted connection is only good for transmitting frequencies up to about 400 Hz--well within the audible range, as well as something that can be felt. Welds with voids will filter out higher frequencies in a similar manner to bolted connections--not at the same frequency, but they'll behave similarly--making something sound dead when you hit it with a hammer.


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## Eamon Burke (Nov 10, 2011)

Wow! I missed a good thread.



MWhtrader said:


> I have read some literature on the perception of feel, and its mostly comprised of sound and touch. In the golfing world, forged clubs from 1018 steel are regarded to have the best feel, while stainless steels or multimaterial construction are usually described as feeling harsh or disconnected. Also, Mizuno golf uses harmonics (sound) to fine tune the feel of the clubs, where its usually accepted that sound in golf matters more to feel than forge or cast.
> 
> Good thing here is that the knife is a simple geometry, which is a quasi cantilever beam, so I am going to approximate with the simple equations. we would be talking about resonance, which is most affected by length and spring constant(or elasticity modulus ). While I might be stretching a bit, but usually the cladding is shorter than the core, so that would recreate a difference in resonance, difference tend to decrease the overall quality of sound created.
> 
> ...


 
I agree with this, except that your conclusion seems to assert that the feel is better if you are more sensitive to feel, rather than what the information asserts, which is that "feel" is more likely a perceptual satisfaction created by noise. I can get in on this. I think a lot of "feel" on stones is sonic, for the same reasons.


Larrin, your chart shows the difference in elastic modulus for 3 kinds of steel, and it would seem that if the difference between Carbon Steel and Nickel Steel is greater than the difference between Carbon Steel and Cro-Mo steels(which would be stainless cladding, since 13% Cr defines stainless). So it would follow that if the difference in elastic modulus was causing this polarizing "deadness" in feel, then all of the Damascus blades should be even MORE dead feeling, than clad since the difference in modulus is greater.

It would seem that if the information you related is reliable(which I assume it is, since YOU presented it), then the "elastic modulus theory" appears dead, leaving only faulty lamination or observer bias; I feel it is the latter. If pleasant tonality and steel quality were related, we'd be making knives out of tuning forks instead of bastard files.

IME, "feel" has a lot more to do with weight and cutting efficiency. My Yanagiba(AS) will slice through salmon pinbones without me noticing they are there.


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## DevinT (Nov 10, 2011)

The reason that cladded blades feel different is because there is size change after heat treatment in steels causing tension between layers. Steels with the greater amount of carbon in them will grow to a greater amount than steels with less carbon. This is why the Japanese cold forge their blades, to relieve the tension between layers.

Some steels grow quite a lot after hardening, and tempering releives some of this size change but not all. There is always some tension between layers forge welded together. Cladded blades will be stiffer than mono steel blades because of the tension.

Hoss


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## JohnnyChance (Nov 11, 2011)

DevinT said:


> The reason that cladded blades feel different is because there is size change after heat treatment in steels causing tension between layers. Steels with the greater amount of carbon in them will grow to a greater amount than steels with less carbon. This is why the Japanese cold forge their blades, to relieve the tension between layers.
> 
> Some steels grow quite a lot after hardening, and tempering releives some of this size change but not all. There is always some tension between layers forge welded together. Cladded blades will be stiffer than mono steel blades because of the tension.
> 
> Hoss


 
You should have come along earlier and saved us 6 pages!

Thanks Devin.


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## Delbert Ealy (Nov 11, 2011)

DevinT said:


> The reason that cladded blades feel different is because there is size change after heat treatment in steels causing tension between layers. Steels with the greater amount of carbon in them will grow to a greater amount than steels with less carbon. This is why the Japanese cold forge their blades, to relieve the tension between layers.
> 
> Some steels grow quite a lot after hardening, and tempering releives some of this size change but not all. There is always some tension between layers forge welded together. Cladded blades will be stiffer than mono steel blades because of the tension.
> 
> Hoss



Devin,
With the cladding that is normally used(a 300 series stainless) the cladding acts more like a non-ferrous metal than steel and the rules for hardening those are very different than for steel. The "cold forging" will harden the cladding(adding stress) rather than relieving it. 
Del


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## DevinT (Nov 11, 2011)

Del,

Most are using 403, 410, 416 etc. The Japanese cold forge before heat treating and any stress is relieved during HT. It does cause some hardening but it also causes the cladding to grow and during HT the core catches up with the growth of the cladding.

The Japanese claim that the cold forging is for grain refinement, which it does.

Hoss


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## Eamon Burke (Nov 11, 2011)

Dang it, hoss, do you have to know everything? We were having a perfectly valid bullshyte session.


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## Delbert Ealy (Nov 11, 2011)

Devin,
With the way you worded it "after heat treatment in steels causing tension between layers.............cold forge their blades, to relieve the tension between layers." it sounded to me like you meant they cold forge after heat treatment. 
Are you sure they are using 400 series, because if they are then there should be some activity like Bill Burke gets on his blades. The Cramer I had on loan for a bit was clad with a 300 series and that is what I based my above statement on. Them using 300 series stainless would also explain some people feeling a difference in the clad blades over monosteel blades.
Thanks,
Del


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## DevinT (Nov 11, 2011)

Del,

Size change happens because of HT. Most steels expand when hardened and shrink a little when tempered but still have a net gain. All damascus (pattern welded) and clad materials have some tension after HT. That is the point here.

The Japanese use low carbon 400 series martensitic steel for cladding.

Hoss


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## Delbert Ealy (Nov 11, 2011)

Just checking out carters site and that was 410 clad, so I guess I was wrong about that, I am surprised that there is no activity in his blades, maybe they use a thin nickel layer to avoid it.
Devin, I know about the size changes during heat treat, I have seen clad blades blown apart because of the streeses of heat treat, with the primary steels I choose to work with, and the style of knives I make, it just isn't much of an issue. O-1 is one of the most stable as far as size goes of all the tools steels. 
Del


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## mpukas (Nov 12, 2011)

DevinT said:


> The reason that cladded blades feel different is because there is size change after heat treatment in steels causing tension between layers. Steels with the greater amount of carbon in them will grow to a greater amount than steels with less carbon. This is why the Japanese cold forge their blades, to relieve the tension between layers.
> 
> Some steels grow quite a lot after hardening, and tempering releives some of this size change but not all. There is always some tension between layers forge welded together. Cladded blades will be stiffer than mono steel blades because of the tension.
> 
> Hoss



Thanks for all the great info Devin, and for setting the record stright!!! :thumbsup: 

My interpretation of what you have said re: my original question of clad v mono, is that a clad blade being stiffer will provides less feedback during cutting since it will resonate less. Not that one is better than the other, just different, and not everyone likes the same thing. Cheers! mpp


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## tk59 (Nov 12, 2011)

mpukas said:


> ...a clad blade being stiffer will provides less feedback during cutting since it will resonate less...


Hmm. I didn't really get the same thing exactly. Stiffness would just change the frequency of the vibration, wouldn't it? If anything, it sounds like having two bells with different frequencies touching. Maybe they don't ring as well.


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## mpukas (Nov 12, 2011)

tk59 said:


> Hmm. I didn't really get the same thing exactly. Stiffness would just change the frequency of the vibration, wouldn't it? If anything, it sounds like having two bells with different frequencies touching. Maybe they don't ring as well.


 
I think we're pretty close to being on the same page. I'm just trying to formulate what's going on into a simple sentence.


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