Quantcast
mono v clad; ground v forged - Page 6
+ Reply to Thread
Page 6 of 7 FirstFirst ... 4567 LastLast
Results 51 to 60 of 63

Thread: mono v clad; ground v forged

  1. #51
    Senior Member Lucretia's Avatar
    Join Date
    Oct 2011
    Location
    Isle of Lucy
    Posts
    1,610
    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.

  2. #52

    Join Date
    Mar 2011
    Location
    Rockport, TX
    Posts
    4,892
    Wow! I missed a good thread.

    Quote Originally Posted by MWhtrader View Post
    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.
    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.

  3. #53
    DevinT's Avatar
    Join Date
    Mar 2011
    Location
    Panaca, NV.
    Posts
    760
    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

  4. #54

    JohnnyChance's Avatar
    Join Date
    Feb 2011
    Location
    CT
    Posts
    3,029
    Quote Originally Posted by DevinT View Post
    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.
    "God sends meat and the devil sends cooks." - Thomas Deloney

  5. #55
    Delbert Ealy's Avatar
    Join Date
    Feb 2011
    Location
    Indian River, MI Just under The Bridge
    Posts
    1,034
    Quote Originally Posted by DevinT View Post
    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

    Laminated metals specialist, Kitchen knife and gadget maker
    www.ealyknives.com
    www.mokume-jewelry.net
    "Build a man a fire and he will be warm for a day, set a man on fire and he will be warm for the rest of his life"

  6. #56
    DevinT's Avatar
    Join Date
    Mar 2011
    Location
    Panaca, NV.
    Posts
    760
    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

  7. #57

    Join Date
    Mar 2011
    Location
    Rockport, TX
    Posts
    4,892
    Dang it, hoss, do you have to know everything? We were having a perfectly valid bullshyte session.

  8. #58
    Delbert Ealy's Avatar
    Join Date
    Feb 2011
    Location
    Indian River, MI Just under The Bridge
    Posts
    1,034
    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

    Laminated metals specialist, Kitchen knife and gadget maker
    www.ealyknives.com
    www.mokume-jewelry.net
    "Build a man a fire and he will be warm for a day, set a man on fire and he will be warm for the rest of his life"

  9. #59
    DevinT's Avatar
    Join Date
    Mar 2011
    Location
    Panaca, NV.
    Posts
    760
    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

  10. #60
    Delbert Ealy's Avatar
    Join Date
    Feb 2011
    Location
    Indian River, MI Just under The Bridge
    Posts
    1,034
    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

    Laminated metals specialist, Kitchen knife and gadget maker
    www.ealyknives.com
    www.mokume-jewelry.net
    "Build a man a fire and he will be warm for a day, set a man on fire and he will be warm for the rest of his life"

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts