the_fantastic_ms_fox (![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
the_fantastic_ms_fox) wrote2009-09-15 08:24 pm
the_fantastic_ms_fox) wrote2009-09-15 08:24 pm
The sword is folded between eight and fourteen times.
When someone says that "the steel in this ______* sword is folded over one-thousand, or sixty-five thousand times," this is what it means:
You start with four layers of metal: two of a hard steel for cutting and two of a soft steel for flexibility. You get them so hot that they fuse together at the edges. Then you hammer them out and fold them. Now you have eight layers. Another heat and another fold is sixteen layers. And so on.
The sword is not actually folded a thousand times. It's folded between eight and fourteen times. This makes between 1024 and 65536 layers of steel. If you want over a million** layers, as i've heard from time to time, fold it eighteen times.
This still requires a lot of skill, as it needs to be flat, and smacking the sword the wrong way could easily puncture a layer of steel. And you don't want to repeatedly heat and cool something that thin, because you'll lose a bit of steel and structural integrety every time. This means that you need to get several people pounding the sword at once, with great accuracy and fine rhythm, and without accidentally sledgehammering each-other.
And you need to temper the sword right, heating the whole sword and getting the whole cutting edge to hit one temperature and the back another before you cool it. And then you need to sharpen it just right. And then you need to figure out which swords are good, which to recycle, and which to sell at a discount under a fake name.
But there is not some _______* blacksmith hunched over a forge, folding it a thousand, or sixty-five thousand, times, or a million times. That would be silly. Never mind the time involved. If you truly folded a sword fifty times, you'd split it's atomic nuclei several times over. If you tried, you'd just mash the layers together to make a lump of steel that varies between thin layers and an alloy, and which, when you went to use it, would bend in interesting ways.
I am learning a lot in this class.
* Insert a nationality here. Blades from cooking knives to scythes, from Switzerland to Burma are made like this. But for some reason the word is usually "Japanese," which makes me hope that Honshu bladesmiths are having a collective mathematical giggle at the rest of the world. It also makes me think that North America has some stereotypes about the Japanese (obsessively skilled but dull - suitable for repetitive factory work) that resemble 1900-era Euro Vancouver's assumptions about Chinese servants. But until word gets around, I can always change my name to Keiji and hire a model to stand in for me on the "about us" section of the website.
**1048576 layers, to be precise. The same number of layers as bytes in a megabyte
You start with four layers of metal: two of a hard steel for cutting and two of a soft steel for flexibility. You get them so hot that they fuse together at the edges. Then you hammer them out and fold them. Now you have eight layers. Another heat and another fold is sixteen layers. And so on.
The sword is not actually folded a thousand times. It's folded between eight and fourteen times. This makes between 1024 and 65536 layers of steel. If you want over a million** layers, as i've heard from time to time, fold it eighteen times.
This still requires a lot of skill, as it needs to be flat, and smacking the sword the wrong way could easily puncture a layer of steel. And you don't want to repeatedly heat and cool something that thin, because you'll lose a bit of steel and structural integrety every time. This means that you need to get several people pounding the sword at once, with great accuracy and fine rhythm, and without accidentally sledgehammering each-other.
And you need to temper the sword right, heating the whole sword and getting the whole cutting edge to hit one temperature and the back another before you cool it. And then you need to sharpen it just right. And then you need to figure out which swords are good, which to recycle, and which to sell at a discount under a fake name.
But there is not some _______* blacksmith hunched over a forge, folding it a thousand, or sixty-five thousand, times, or a million times. That would be silly. Never mind the time involved. If you truly folded a sword fifty times, you'd split it's atomic nuclei several times over. If you tried, you'd just mash the layers together to make a lump of steel that varies between thin layers and an alloy, and which, when you went to use it, would bend in interesting ways.
I am learning a lot in this class.
* Insert a nationality here. Blades from cooking knives to scythes, from Switzerland to Burma are made like this. But for some reason the word is usually "Japanese," which makes me hope that Honshu bladesmiths are having a collective mathematical giggle at the rest of the world. It also makes me think that North America has some stereotypes about the Japanese (obsessively skilled but dull - suitable for repetitive factory work) that resemble 1900-era Euro Vancouver's assumptions about Chinese servants. But until word gets around, I can always change my name to Keiji and hire a model to stand in for me on the "about us" section of the website.
**1048576 layers, to be precise. The same number of layers as bytes in a megabyte