2,700 folds

N

never2many

Joined
Nov 17, 2003
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I saw a awesome knive a few days ago. I wish I could recall who made it. (I suck at names.) Anyway, it was a Damascus fixed blade with 2,700 folds. It looked wild. The metal was almost moving like water.

I am new to the tech/high-end knife world. So maybe that many folds is no big deal, but I was quite amazed. Oh yeah, it was only $350.00. I wish I had the cash. Oh well.

Chris
 
Do the math.By the time you folded it 2700 times you would have a homogeneous material ,not different layers.Each time you fold you double the number of layers.Even if you had 2700 layers you would have the same thing . The problem is too many people don't know their math and too many are full of BS.
 
So where did you see this knife? Is there a picture that we can look at. You can get a good idea of the actual number of layers from the appearance of the blade. mete is right, if there were 2700 hundred layers it would look like one homogeneous piece of steel.
 
That is not a lot of folds really.........2x2x2x2x2x2x2x2x2x2x2, maybe one more than that.....but a lot of the best sword makers in Japan used to fold their blades quite a bit, for strength....and after they polished them you couldnt see any of the layers.
 
For 350? An expertly forged blade? Is this for real, or a Ginsu special? I would vety much like to have more details. Who is this maker?
 
A common misconception in the world of pattern-welded steel (it pops up often in the Japanese sword world) is the number of folds versus number of layers.

Layers is an approximate figure as well, as "layers" get burned off as scale and are distorted or close enough together that they become homogenous.

You will typically see Japanese style swords folded between 6 and 10 times, though you cannot really differentiate "layers" as a layer is made up of many individual chunks. However, there are often blades with well over 10,000 "layers" that actually do exhibit visible hada (forge-welded pattern). Granted, it is quite fine and does not look significantly different from an appropriately-made 1000-2000 layer billet, but it is not totally homogenous and invisible!

Further, Japanese steel was forge welded predominantly to rid the material of impurities and to convert many little chunks of fairly crude simple steel into usable billets from which they made the blades. Strengthening and adding elements to the steel is for the most part untrue, though there may be traces of things like Si and a little bit of C added (though you lose a little bit of C with the forge-welding). Typically, each weld poses the risk of detrimental flaws, and as a result you don't want to weld more times than necessary to get a good workable billet from.

Sorry for veering away from the topic :)
 
1 fold = 2 layers
2 folds = 4 layers
3 folds = 8 layers
4 folds = 16 layers
.
.
.
10 folds = 1024 layers
11 folds = 2048 layers
12 folds = 4096 layers
.
.
.
2700 folds > 99,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000

assuming all folds are complete doublings and that no layers are lost along the way.

So, getting to 2700 layers is not to hard. Making 2700 folds???? No.
 
Traditionally made Japanese swords are usually folded about 10-15 times. I know that Yoshinda Yoshihara stops at 12-13.
 
Beluga: You'll find that a lot of historical and most contemporary smiths stop earlier than Yoshihito, who has a power hammer I believe at his disposal. But yeah, 10-15 is also not terribly uncommon, and there are always folks who think more = better!

Also for the layer calculation, bear in mind that you don't always start with a single layer billet when you do your first "fold"...it is not terribly uncommon to see a 3, 5, or even 7-8 layer stack welded and then folded on itself. That gets the layer multiplying started just a wee bit earlier. There are also people who make 2 separate billets of maybe 5 initial layers, forge-weld them individually to create a few dozen (or hundred!) each, then forge weld those together with homogenous steel or cable or any number of things.

Layer count doesn't really mean a whole lot, though it is a safe bet that "20 billion layers" would suggest dishonesty, and 2000 layer may suggest a finer pattern than say 200 (no guarantees though). The numbers themselves are somewhat arbitrary, and only truly serve the purpose of pointing out that a maker most likely put some work into it. It's still fun to use those arbitrary numbers to get "oohs" and "ahhs" though...:D
 
If you start with five layers, then the math is a bit different:

1 Fold = 10 Layers
2 folds = 20 layers
3 folds = 40 layers
4 folds = 80 layers
5 folds = 160 layers
.
.
.
9 folds = 2560 layers
10 folds = 5120 layers


The conclusion is the same. Getting 2000+ layers isn't unreasonable. But getting 2700 folds would be impossible.

Another way to look at it is thickness. Assume that the finished blade is 1/4" thick (which is a pretty thick blade). If it's made of 2000 layers, each layer is 125 millionths of an inch thick. A typical piece of office paper is about 400 millionths of an inch thick. If you take a ream of paper and look at the side of it carefully, you can barely make out the individual sheets with your naked eye. So, metal layers 1/3 of that thickness should be visible too, but just barely. A ream of office paper is 500 sheets and it's typically about 1.5" thick. Now, pack four times as many layers into 1/6 the thickness.

Take the example in this post that starts with five layers. Fold it twelve times and you end up with about 20,500 layers. Again, if it's 1/4" thick, then each layer is just 12 millionths of an inch thick. You'd need at least a 10x magnifier to barely see those layers.

So, just a little bit of thinking enables us to discard the 2700-fold claim.
 
I think that when people make these claims of very high numbers of folds that they are actually referring to layers and are just using the wrong terminology.

I have seen a few 10,000 and higher layer steels. Some appeared no different than regular steel and some had a very interesting wavy pattern. You couldn't see layers, but this wavy look to the steel was fascinating and somewhat mesmerizing.
 
Steel in high layer count does not necessarily mean every layer is distinct or every layer blends with the one next to it (thus making roughly homogenous steel). When you look at forge-welded steel (particularly similar-composition billets) with very high layers, more than anything you are seeing the gunk/impurities that reside in the weld seams, some are cleaner than others and are effectively muted, while others show rather prominently. That for the most part is what makes hada visible. Just because the steel has "20,000 layers" doesn't mean you can count 39,999 lines (layer/seam/layer...).
 
Originally posted by Keith Montgomery
I think that when people make these claims of very high numbers of folds that they are actually referring to layers and are just using the wrong terminology.
Click to expand...

Ha, you got me. As I stated on my first post of this thread, I am slightly new to the highend knife world. I did use improper terminology. What I should have typed is layers not folds. Sorry for the mix up guys.

I have been looking for the guys card,(the dealer selling the knife makers product) but so far I have had no luck. I may have thrown it out with my wetterlings axe paperwork. I wish I could give you guys a good link or pics, but as I said my ability to recall names has tossed a wrench in the gears. All I can say is that all of the "layers" were visible. The pattern was not really stacked as you might think, but appeared more flowing like fine wood grain.

Thanks,
Chris
 
and there are always folks who think more = better!
Click to expand...
I must admit that i thought that. i know nothing of swords except that ancient samurai katanas were folded a bunch of times. so what is the best number of folds? 12-13? is a folded steel katana a better user than a powdered steel katana?
 
Neither is inherently better. It's just steel. With old-fashioned stuff you are more prone to fatal welding flaws and stuff, whereas "powdered steel" is much more pure and less likely to include significant flaws.

The number of folds has little or nothing to do with "strength" or "toughness" or any other qualities that people believe make good blades. Historically, it was to make the steel usable and cleaner (not to make it sharper, hold an edge longer, resist bending better, etc...none of that really was the objective of forge-welding), now it is done primarily for aesthetics. The number of folds CAN be used to determine how "fine" a pattern you want in some instances, though this is also not always the case, particularly once you start going over 1000 hypothetical layers.

You can make a perfectly fine blade from 1 bar of steel without any forge-welding. You can make a perfectly fine blade from an intermediate layer-count billet, or a high layer billet too! I think folks want to attach meaning to forge-welded stuff, and aesthetic pleasantries just doesn't seem to be enough for most of the "form follows cost follows function" folks that are very widespread on these forums.

Sorry if I'm inadvertantly hijacking this thread!
 
EDIT: IGNORE--Gross failure of human-calculator interface and common sense! Gollnick is correct.
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Hmmm, my trusty calculator tells me that 2 taken to the 2,700th power is in the neighborhood of 7.3 times 10 to the 6th power, or about 7,300,000.

Certainly not as large a result as Gollnick's extrapolation, but this IS a large number. (modern finance aside)

1/4 inch is about 0.6 cm

The hypothetical 1/4" 2,700 fold blade would be comprised of layers about 8.3 X 10^-8 cm thick.

Roughly speaking, an iron atom is about 1.3 X 10^-8 cm in diameter. So each layer in our hypothetical blade is 6 atoms thick.

The shortest wavelength detectable by the human eye is about 4 X 10^-5 cm, about 2,000 times larger than the thickness of the hypothetical layers. No light visible to the human eye can resolve features of this size. High-energy x-rays or low-energy gamma rays are needed to resolve features the size of the layers in this hypothetical blade.
END OF PART OF POST MADE WITH BRAIN IN IDLE

9.8 X 10^99 iron atoms has a mass vastly greater 10^50 than that of the earth.
-------------------

A blade with layers (or more accurately, distance between layer boundaries) about the same order of magnitude (very roughly, 10^-4 cm or 10,000 folds/cm) as the wavelength of light could exhibit some properties similar to a diffraction grating, depending upon the surface finish. Since the folds in the blade would not be as regular as a true diffraction grating (as noted by R. M.), the resolution of visible light into colors would probably not occur, but the a shimmering effect due to partial interference of the reflected light could occur. Once the layer-boundaries are separated by a distance smaller than the wavelength of visible light, the effect cannot occur.

The distance between the layer boundaries will depend upon what angle the blade surface intersects the stacked layers. Some parts of the blade could act similar to a difraction grating, while others did not, depending upon the folding, creating the appearance of a permanent pattern.
 
Your math is wrong. 2700 squared is 7,290,000. 2 to the 2700th power is vastly greater. My calculator says 6.039 times 10 to the 812th.
 
my calc agrees with Robert. looks like firkin just hit a wrong button, but the rest of his stuff is pretty interesting.
 
doh!

yes Gollnick (and Robert are correct), and it is so noted in the post.


Now there are layers a miniscule fraction of an atom thick.

or a single stack of atoms in a blade that weighs something over 10^50 X the mass of the earth.


The part about diffraction is I believe, correct.
 
And from another perspective, think of material cost.

Imagine how much material you would lose to oxidation/scale over the process of making one blade billet. Then calculate the amount of time it would take to perform each cycle and ensure that the weld is good, then weld again...a few thousand times.

It's pretty superfluous after about 15 cycles, and some may argue it's kinda superfluous quite a bit before that number!
 
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