DAMASCUS – Functional Knife Blade or Art?

thanks Ed!


thinking about the micro serration thing, how would this compare to an edge sharpened at say 120 grit? wouldn't the effect be similar?
 
severedthumbs said:
thanks Ed!


thinking about the micro serration thing, how would this compare to an edge sharpened at say 120 grit? wouldn't the effect be similar?
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120 is pretty ragged. The micro-serrations on a blade like the 3000 plus layer ones that Don Hanson makes from 20% low carbon and 80% W2 MOL would be much finer, I would think.
 
jdm61 said:
120 is pretty ragged. The micro-serrations on a blade like the 3000 plus layer ones that Don Hanson makes from 20% low carbon and 80% W2 MOL would be much finer, I would think.
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granted 120 is quite exaggerated but doesn't any sharpened edge have micro serrations on some level? I'm just trying to understand this one.
 
from spyderco

serrations.gif



Even a properly sharpened plain edge will exhibit vertical scratch patterns with "micro-serrations" that enable the edge to cut efficiently (Diagram C)
 
The bottom line is that most people like damascus because it looks cool. But it should be able to perform. Hence the aversion some smiths have to using pure nickel on the edge.
 
severedthumbs said:
from spyderco

serrations.gif



Even a properly sharpened plain edge will exhibit vertical scratch patterns with "micro-serrations" that enable the edge to cut efficiently (Diagram C)
Click to expand...
Assuming that you sharpen the perpendicular to the long axis of the blade throughout the entire process. A polished edge will still have micro-serrations, albeit VERY tiny ones. Even the edge of a microtome is not going to be "perfect" The question becomes how big you want the "teeth" to be. The theory of the "damascus cutting effect" may be that the soft layers abrade faster than the hard layers, so the knife is essentially "self sharpening" up to a point because you are continually exposing new bits of the hard layers as you cut. Whether that is true or not is the subject of MUCH discussion.
 
The "micro-serration" doesn't work exactly the same way on a straight steel blade, but somewhat similar. The reason is that a straight steel blade is a single, homogeneous steel, that is generally all the same hardness.
In a mix of high and low carbon damascus, the low carbon material sharpens away at a different rate than the high carbon layers, which is what creates the effect on that type of damascus blade. Due to the hard/soft structure, this effect will continue to be prevalent as you use this type of blade.
Similar cutting characteristics can be achieved on straight steel by sharpening with a fine India stone, or a worn out 400 grit belt, and then NOT knocking off the wire edge thats left. The difference is that the straight steel blade's "serrated" edge will wear away more quickly, and hence will SEEM to dull more rapidly than the same edge on a high/low carbon damascus blade.

There are basically two type of final edges that I apply to knives. A "working" edge is what I will usually apply to a hunting type knife, which I do by using either a fine India stone or a worn out 400 grit belt at very slow speed. This edge will not always be "hair popping" sharp, but it is very aggressive and works/lasts well for using applications.

The other type of edge that I apply is for customers whom I know will want to impress their friends by shaving hair from their arm, or slicing paper, etc. is slightly different....... I apply this edge in the same manner, but add the step of lightly buffing the edge on a loose buffing wheel with pink no-scratch compound. This knocks off the wire edge, and produces a "razor" edge, that is "scary" sharp. Although this type of edge is "sharper" it is not necessarily the best edge for using type situations.

Again, we're back to the variables. Theres a ton of them involved. If you want to compare edges, and are planning on using a belt to sharpen, I would encourage you to NOT go any heavier than a worn out 220 grit belt. A 120 will remove much more material than what you realize, creating larger edge bevels, which in turn will increase the cutting resistance, and make the edge seem dull. The devil is always in the details. Experiment and find what works best for you. Didn't mean to get so far off the subject, but again, I felt it needed to be explained.
 
Ed Caffrey said:
The "micro-serration" doesn't work exactly the same way on a straight steel blade, but somewhat similar. The reason is that a straight steel blade is a single, homogeneous steel, that is generally all the same hardness.
In a mix of high and low carbon damascus, the low carbon material sharpens away at a different rate than the high carbon layers, which is what creates the effect on that type of damascus blade. Due to the hard/soft structure, this effect will continue to be prevalent as you use this type of blade.
Similar cutting characteristics can be achieved on straight steel by sharpening with a fine India stone, or a worn out 400 grit belt, and then NOT knocking off the wire edge thats left. The difference is that the straight steel blade's "serrated" edge will wear away more quickly, and hence will SEEM to dull more rapidly than the same edge on a high/low carbon damascus blade.

There are basically two type of final edges that I apply to knives. A "working" edge is what I will usually apply to a hunting type knife, which I do by using either a fine India stone or a worn out 400 grit belt at very slow speed. This edge will not always be "hair popping" sharp, but it is very aggressive and works/lasts well for using applications.

The other type of edge that I apply is for customers whom I know will want to impress their friends by shaving hair from their arm, or slicing paper, etc. is slightly different....... I apply this edge in the same manner, but add the step of lightly buffing the edge on a loose buffing wheel with pink no-scratch compound. This knocks off the wire edge, and produces a "razor" edge, that is "scary" sharp. Although this type of edge is "sharper" it is not necessarily the best edge for using type situations.

Again, we're back to the variables. Theres a ton of them involved. If you want to compare edges, and are planning on using a belt to sharpen, I would encourage you to NOT go any heavier than a worn out 220 grit belt. A 120 will remove much more material than what you realize, creating larger edge bevels, which in turn will increase the cutting resistance, and make the edge seem dull. The devil is always in the details. Experiment and find what works best for you. Didn't mean to get so far off the subject, but again, I felt it needed to be explained.
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thanks again Ed. a worn 220 slack seems to be the general consensus.
 
severedthumbs said:
thanks again Ed. a worn 220 slack seems to be the general consensus.
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But not too slack. Either up close the idler/contact wheel or, if you can afford it, on something like Rob Frink's rotary platen. I recall that Ed's platen has a two inch or so gap between the top of the platen and the top wheel just for that purpose.
 
About 900-1100 AD the Chinese twisted a high layer count billet and then folded once and then probably laddered the edge. You have opposing twists at opposite angles waving down the edge of the blade. Depending on the mix and the durability of the steels this method was designed to optimize the number of layers and opposing grain at the edge to give the best Damascus cutting effect...Take Care...Ed
 
I don't believe modern damascus could have gotten as popular so fast based on mere artistics alone but more a combination of both artistic appeal and functional performance.

I believe we can deduce from the abundance of knowledgeable discussion here that damascus properly forged from preferred material can perform at least as good as it's forged counterpart.
 
Ed Schempp said:
About 900-1100 AD the Chinese twisted a high layer count billet and then folded once and then probably laddered the edge. You have opposing twists at opposite angles waving down the edge of the blade. Depending on the mix and the durability of the steels this method was designed to optimize the number of layers and opposing grain at the edge to give the best Damascus cutting effect...Take Care...Ed
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Mr. Schempp and Mr. Caffrey thank you for taking the time. I have a question I hope you or someone would answer. The type Damascus you speak of that the Chinese where making in todays more popular patterns which is closest to that type. Wire damascus ? What is the best so to say cutting pattern out there. I know it is probale negligable but if ya had to give one the nod which would it be?? Thanks
 
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Using modern materials, properly heat treated, with appropriate edge geometry for the material, it would take a lot more work and experimentation than I have done be able to to say which is best. Most all resonable Damascus can be excellent.

1000 years ago you might of had to trade your step-sister to get enough good high Carbon material for one blade. Each batch of "good" steel was quite different and relied on the skills of the experienced smith to yield a quality blade.

Now we can spec our steel and deliver the best mix for the project at hand.

When I make prototype for Spyderco; I use Damascus steel. Sal wants me to use homogenous steel to get a better evaluation amonst all the prototypes that Spyderco displays. Then no one asks him if Spyderco is going to build the Damascus knife. So I don't etch the steel; and no one has ever noticed that the pieces are Damascus. With modern materials and good technique, modern Damascus is very good homogenous cutting material....Take Care...Ed
 
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