Page 1 of 2 12 LastLast
Results 1 to 10 of 11
  1. #1
    is Over 9000!!!!
    Join Date
    Aug 2009
    Posts
    679
    Thanked: 326

    Arrow Process of making Tamahagane

    My understanding has significantly increased after watching these and I thought some of you might find it informational if not interesting to say the least.

    Now know why it's so expensive and they sure weren't kidding when they said the process for manufacturing Tamahagane is well over 36 hours. I've been up longer than 36hrs before but it sure as hell didn't entail working under severe intense condition. Indeed, it doesn't get much closer to perfection than this.

    What is Tamahagane or Traditional Japanese Steel ?



    Property Type: Japanese Sword Forging



    Steel is iron that contains carbon, so the more carbon a steel has , the harder it is. Most of the Japanese sword smiths are working with the traditional steel that is better known as tamahagane. In Japan thereís only 1 official smelter left. This Japanese style smelter is called a tatara. The tatara relies on the propensity of very hot iron to combine with carbon in its vicinity to produce steel.


    In the tatara, it is the burning charcoal that supplies the carbon. These typical Japanese smelter is made of clay, about 5 feet wide, 48 inches tall and 15 feet long, where itís walls are 10 inches thick.


    One operating cycle of the tatara takes 5 days. One day to build the walls (clay and sand), 3 dayís to smelt and 1 day to remove the iron out of the tatara. In this 5 days process , they need about 13 tons of charcoal and 8 tons of satetsu (black sand) to produce 2 tons of iron and steel, which is called Kera.


    About half of this Kera is composed of steel ranging from 0.6 to 1.5% carbon and it is this portion that is called tamahagane. Only Two thirds of the tamahagane is of a good quality. The rest of the Kera can be used for forging swords if another separated forging operation is done, this process is called Oroshigane, where carbon is added or reduced.


    Every time Tamahagane need to be made, the tatra needs to be rebuild. Its walls must be build out of clay bricks. The mixture that is used to make the bricks does contain a large amount of sand (silicon oxide) which makes the tatra resistant to fire and melting.


    Since the forging process of a sword produces a continues loss of carbon, most of the smiths like to start with tamahagane that has an carbon content of 1.0 to 1.5% to forge the kawagane (jacket steel).


    A billet of tamahagane from the tatara furnace is very big (as you can see in the video) and includes various qualities of steel. The big Ďrockí of Tamahagane is broken into many small pieces to check the quality.
    From here on the smith can choose the right pieces and start the forging process of this katana.



    Here's another




    Tamahagane is smelted very much the same way today as it has been for centuries. As always there are considerations taken into account. People being as close as they are to one another in Japan, the smelting process has an immediate and direct effect to the surrounding land; usually shared by farmers. So, as it goes they came to an agreement and limited the manufacturing of Tamahagane to three weeks per year in some areas.
    This social contract is an understanding and mutual agreement between land users sharing their environment with a Tatara. I get the sense there are only a small handful of Tatara throughout all of Japan, so donít think this is norm for Japanese; but it is a great example.


    The Tatara, or Japanese smelter, has virtually no mechanization. Once started, the process is a 72 hour commitment on behalf of the Tatara master and his crew. They continuously shovel prepared charcoal into a huge burning oven made of clay. The main ingredient, iron sand, is usually collected from the riverbed nearby. The sand and river, of course, is the dual reason farmers and the Tatara share land.


    At the end of the three day/night fire, an uneven mixture of iron, nickel, silicon, carbon and other elements is formed at the bottom of the Tatara. The clay walls are smashed and a meteor looking piece is hauled from the base. Altogether the final solid mass weighs well over a ton. Itís then processed into small pieces and distributed mostly to sword smiths in Japan.


    Itís understood that Tamahagane manufactured in Japan should not leave the country for sword production purposes in other countriesÖ although I donít know if itís an illegal act or not, the fact it would be mostly frowned upon is enough to enforce the unspoken rule. The only flexibility Iíve seen with this rule has been for demonstration purposes, when Japanese smiths travel to other countries.

    Tamahagane is the impure base material for the Japanese sword. Itís the core element in the most famous weapon manufactured. There are many variations and practitioners outside of Japan, but in Japan it has been carefully preserved and resurrected (since WWII) to a point where many consider todayís practitioners as good any era.

    More info on steel
    What I thought was interesting was when narrator admitted to only being trained with calculators and such. That he's never been able to properly judge steel temperature by gauging it's color.

    I wonder if it's same process they use when it comes to applying hamon on the kamisori.

    Cliffs:

  2. The Following 6 Users Say Thank You to SiRed8 For This Useful Post:

    avatar1999 (10-29-2009), ChrisL (10-29-2009), ISaid (11-08-2009), Jasongreat (01-31-2010), jballs918 (10-29-2009), Steelforge (10-29-2009)

  3. #2
    "My words are of iron..."
    Join Date
    Oct 2006
    Posts
    1,857
    Thanked: 947

    Default

    That's a fairly decent summary. Several of my good acquaintances and friends in those vids and excellent craftsmen.

    To dispel some of the myths about clay...while it is used to guide and develop the shape of the hamon on largish blades, its basic function is much more simple. It really keeps oxygen in the fire from causing scale on the surface of the blade, leading to more work after heat treatment that could be avoided.
    "Nearly all men can stand adversity, but if you want to test a man's character, give him power." A. Lincoln.

  4. #3
    I used Nakayamas for my house mainaman's Avatar
    Join Date
    Aug 2009
    Location
    Des Moines
    Posts
    8,453
    Thanked: 2501
    Blog Entries
    1

    Default

    I wonder if anyone had seen razor made from tamahagane?
    that thing might have the longest edge retention ever, and the longest honing time ever too???
    Stefan

  5. #4
    Forum mogwai thebigspendur's Avatar
    Join Date
    May 2005
    Location
    New Mexico
    Posts
    27,500
    Thanked: 4359
    Blog Entries
    4

    Default

    Several years ago Iasaki had a site up (in Japan of course) several pages long with photos of him at the forge making his razors. I don't know if its still up or not but it was interesting. Too bad I didn't write the site down.
    Every day without fail one should consider himself as dead-Tsunetomo

  6. #5
    Senior Member blabbermouth JimR's Avatar
    Join Date
    Dec 2008
    Location
    Japan
    Posts
    2,743
    Thanked: 1010
    Blog Entries
    2

    Default

    Quote Originally Posted by thebigspendur View Post
    Several years ago Iasaki had a site up (in Japan of course) several pages long with photos of him at the forge making his razors. I don't know if its still up or not but it was interesting. Too bad I didn't write the site down.

    Well, there's this: 岩崎重義の世界

    It's not got a LOT of pictures of him at the forge, but it's got some real beauties of his knives. And a lot of history, if you can work out the Japanese.

  7. #6
    Forum mogwai thebigspendur's Avatar
    Join Date
    May 2005
    Location
    New Mexico
    Posts
    27,500
    Thanked: 4359
    Blog Entries
    4

    Default

    No not the same site however his razors are there and if you noticed a western style razor also.
    Every day without fail one should consider himself as dead-Tsunetomo

  8. #7
    is Over 9000!!!!
    Join Date
    Aug 2009
    Posts
    679
    Thanked: 326

    Arrow

    Quote Originally Posted by mainaman View Post
    I wonder if anyone had seen razor made from tamahagane?
    that thing might have the longest edge retention ever, and the longest honing time ever too???
    They're indeed very expensive but IIRC k990 steel is nearly impossible to differentiate with the Tamahagane. Please correct me I'm still learning.

    In one of those vids it's even said "if a samurai isn't made in tamahagane it's not considered authentic..."

    Geez mate I know how precise and surgical Japanese culture are in general but I found it disconcerting when the bloody narrator said that. Perhaps that me being ignorant...

    That's like me saying "the Japanese razors are by far the best shavers out there I'm gonna set the blinders on because every razor out there is POS" :crook:

    Then again the J-spec razors are asymmetrical and one can't really compare as they are different. Same classification but different breed-like econbox Civic in comparison to an STi. They're both cars where the latter is watered down vehicle of WRC counterpart and the former is gas saving beater. I don't know perhaps I'm over-thinking this just a little...

  9. #8
    "My words are of iron..."
    Join Date
    Oct 2006
    Posts
    1,857
    Thanked: 947

    Default

    K990 steel is essentially the same as W1. It would make a fine razor. It is not tamahagane, nor equivalent. First the production process disqualifies it and second the carbon content is way off.

    After WWII, the US decided to allow the Japanese to restart the tamahagane smelter. There was a huge political argument that this would allow for a restart of a weapons industry, and would result in continuing the Japanese warrior culture leading to more trouble in the future, but some argued successfully with MacArthur regarding the "art" involved in making swords and how much importance the sword had as a cultural icon in Japan.

    Given the trouble they went through to get the smelter restarted, the reservation of tamahagane for art objects like swords, or tools (chisels, razors etc.) where a famous smith wanted to produce something special, was a natural extension of the mystique about tamahagane. It was special steel available only to special people. Even now it's made under specific conditions. Even if I was invited to watch one of the big smelts, I suspect I would not be allowed to hang around to work or take other than only limited pictures. This is not because I would take away any secrets, there really aren't any, but because my spirit might contaminate the environment. I might take umbrage at this because I believe I respect their craft and would not offer them any offence, but it's a general prejudice from the swordsmiths who would not want me contaminating the special product they have to use to make their blades. It's really a Shinto thing for the most part. They don't hedge any bets when making stuff that's special, even appeasing the gods when necessary. But that adds to the flavor neh?

    The authenticity of a nihonto made from tamahagane is derived entirely from the licensing process for swords in Japan. Essentially there is a hierarchical system that must be followed to validate that the smith is approved to make the blade, i.e. comes from an established line of swordsmiths and can show his lineage, that the right materials were used and that no more than two swords per month are made. Technically, all tamahagane is supposed to be reserved only for purchase by authenticated swordsmiths, but I'm sure that an ancient enough toolmaker could get some and there have been bits and bobs of the stuff showing up on internet sites without any linkage to the source or quality of the material.

    I agree that the narration in some of those shows slides in the direction of hyperbole, but they are selling the sizzle not the steak. They have continued the focus on the object rather than the environment.

    Within the context of this thread (and at risk of repeating myself), your signature line by J.R. Torrey is a good one. With regard to nihonto (really any sword type), in a fight, I would worry more about a master (of their particular style) swordsperson armed with a rusty lawnmower blade than the least ranked beginner holding the best sword in the world. It all comes down to training where the edge meets flesh.
    "Nearly all men can stand adversity, but if you want to test a man's character, give him power." A. Lincoln.

  10. The Following User Says Thank You to Mike Blue For This Useful Post:

    ChrisL (11-02-2009)

  11. #9
    Senior Member kevint's Avatar
    Join Date
    Mar 2008
    Posts
    1,875
    Thanked: 285

    Default

    Hi Mike. Isn't it true however that one could refine the raw tamahagane ( the blooms) to get whatever carbon content the smith required?

    What do you usually aim for? .7C

  12. #10
    "My words are of iron..."
    Join Date
    Oct 2006
    Posts
    1,857
    Thanked: 947

    Default

    Good question Kevin. Generally the smelter tries for a carbon content between 1.4-1.6% as bloomed. The smith will reduce the carbon content during the forging into orogshigane according to the recipes of their particular school. An interesting piece of post war research determined that the average carbon content is about 0.60% for most schools tested and one group about 0.7%.

    From my observations, carbon is lost because of the nature of the fire (charcoal), the number of heats and the welding process used to forge the billet of material. Some carbon will diffuse to lower areas of carbon in multiple bar construction of sword billets. The smith will have likely calculated how much will diffuse over how many heats from the steels that he assembles so that he's left with a good carbon content at the cutting edge to retain the usefulness of the tool. This is also a function of time at temperature and it's very interesting to see a Japanese smith forging at temperatures we don't see here much.

    Thinking about this from a different direction...let's say that a really very junior swordsmith was way way down on the pecking order for tamahagane and he gets the um, ah, "leftovers." Not so great and lower in carbon content than they would like. Given their charcoal forges, it's entirely possible to build a fire in such a manner as to manipulate the carbon content by creating a reducing atmosphere deep in the fire. With enough babysitting the steel will uptake carbon under the right conditions. Contrariwise it's possible to do the reverse and cause the billet to lose carbon, but that's the easiest thing to achieve and for the most part they will calculate the loss when getting the work of building the oroshigane.

    Between 0.6-0.7% is the sweet spot for forming hamon (the hardening line every one likes to see). I generally like a steel that is right near the eutectic point between 0.8-0.85% and the Japanese smiths I know grumble because I do. One of the really great things about not having done a traditional apprenticeship is that I am not limited by it. I have the utmost respect for their craft given their requirements. It's not that they don't know or they can't, they choose not to. That's discipline.
    Last edited by Mike Blue; 11-01-2009 at 08:02 PM.
    "Nearly all men can stand adversity, but if you want to test a man's character, give him power." A. Lincoln.

Page 1 of 2 12 LastLast

Tags for this 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
  •