Thanks for the information Mike. Interesting reading, especially about the different hardness in different areas of the blade. Makes you wonder if they practiced differential heat treating or is it a product of just uneven heat treating.

Brion

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Thanks for the information Mike. Interesting reading, especially about the different hardness in different areas of the blade. Makes you wonder if they practiced differential heat treating or is it a product of just uneven heat treating.

Brion

You bet, Brion...

Seemed like one aspect was the very uneven carbon in different areas of some blades. That doesn't account for the few blades not HT-ed at all, though.

A lot of what I liked about the article were the ideas of how fully functional swords could be made. The hugely uneven carbon really struck me. After I mulled it a little, it seemed the quality of the steel was irrelevant to the quality of the product. Maybe I misinterpret... maybe don't understand one thing or another... I'm certainly no student of technical aspects of edged weapons.

Mike

I had not really thought about that Mike. I know that WAY back when the homogenized steel we have today did not exist. They had to manufacture it themselves. That might account for the uneven carbon distribution and the differing hardnesses. Even by the 1100's and later there was some good steel used or they had access to it. The japanese smiths for example. I think the quality of the steel was not irrelevant but possibly they had a limited supply of good quality steel and may have used lesser quality steel also. Such as high carbon steel for the edge and a lesser carbon steel for the body. Interesting to think about. It really makes you respect the old smiths for the quality they turned out with limited resources.

Brion

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I had not really thought about that Mike. I know that WAY back when the homogenized steel we have today did not exist. They had to manufacture it themselves. That might account for the uneven carbon distribution and the differing hardnesses. Even by the 1100's and later there was some good steel used or they had access to it. The japanese smiths for example. I think the quality of the steel was not irrelevant but possibly they had a limited supply of good quality steel and may have used lesser quality steel also. Such as high carbon steel for the edge and a lesser carbon steel for the body. Interesting to think about. It really makes you respect the old smiths for the quality they turned out with limited resources.

Brion

The way I understand it is that the Japanese bladesmiths would often get chunks of both high & low carbon steel (as well as cast iron) from the smelter and had to determine himself which was which and how best to incorporate them. I have often thought that the process of folding & layering their blade steels was done primarily to control carbon levels (though they may not have realized that it was the carbon content that dictated how the steel would harden) They may have simply known that their father, grandfather, great-grandfather, etc. had done it that way and if they did it the same way that it worked.

I have not seen anything definatively showing how european smiths managed controlling carbon levels. They may have done this through smelting or adding carbon during the forging processes.

[Interesting that some blades weren't H/T'ed at all but I guess that a dull sword is still a formidable weapon where a broken one is not.]

Interesting topic. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//biggrin.gi f' class='bbc_emoticon' alt=':D' /> Glad that the steel mill does this for us now.

Gary

I've got a very rough idea how the Japanese made and worked steel, and less about the evolution of both. Like you, Gary, I don't have a clue how 1100 - 1300 Europeans did it. I'd like to know more but there is no way to make the time for it... =[

The hardest thing I come to when trying to wrap my head around swords in history is how much time was spent building and using them... a constant effort and evolution for a commonly used tool.

Mike

The problem with ancient steel making in the west vs. the east is that Europeans tended to be too pragmatic for their own good when it came to recording how things were done. Guilds and schools kept tight secrets but as soon as an innovation or improvement came along, tradition didn’t keep them from quickly discarding the old and running with the new if it would give them an edge. Japan was a different culture, tradition was of extreme importance and even obsolete things were preserved just for their own sake, thus you have 800 year old katanas carefully cared for and in pristine condition, while European swords couldn’t get tossed quickly enough to make room in the hand for firearms. Because of this many misunderstandings have cropped up, and can only be tackled by rolling up ones sleeves and trying to recreate it. I have learned more by actually making my own bloomery material than I ever could have deciphered from books on the topic.

Folks often approach tamahagane as if it is fundamentally different from bloomery steel, but basically they are the same product, just one is made in the tatara and the other in a bloomery hearth (in other words a European tatara, although I prefer to view the tatara as a Japanese bloomery hearth). The reduction process is the same in either furnace, and the resulting material is the same iron carbon system with different methods of post-production processing .

One of the most striking myths to have arisen from the incomplete historical knowledge of the process is the idea of the bloomery process producing only iron and the subsequent forging or other operations adding carbon to make steel. In fact, when you do it, it is hard not to make steel in the hearth and the forging process is almost necessary to remove excess carbon and distribute it evenly- the exact opposite of what we have assumed for a long time.

One of the differences from Japanese to European techniques that may have resulted in slightly different products was the Japanese approach of breaking up and choosing select parts of the bloom, based on carbon content, followed by extensive folding and welding to homogenize. I can’t say exactly how the Europeans did it but I can say what methods I have used which produced very similar results to what you see in the western swords. It is very efficient in material and time to just consolidate the bloom in larger pieces and restack, or “pile”, to build up the mass needed to make the material good and solid. The more homogenously higher carbon blades would probably have been the result of improvements in the bloomery process that allowed for higher yields, e.g. the introduction of the Catalan hearth multiplied production tonnages almost overnight.

As for the deviation in the Rc hardness, it could be the result of carbon content as well as the result of quenching methods. Bloomery material is vastly more shallow hardening than even 10XX series steels and requires you to be on your best game in heating and quenching not to blow it. But I have found that even in material that has been folded up to 8 times one can have a deviation of perhaps over .5% carbon just microns apart in the steel. The hardness in this material is more of an average of the various structures in the area of the test. Micro-hardness tests can be even erratic as it measures each of these structures.

The evolution from iron to steel, or relatively soft to hard, in these swords can be traced in a parallel fashion to the production technology as well as the defensive measures that these offensive weapons were having to deal with. Humans are soft targets and can be dealt with easily with copper or bronze, but then you go from humans covered with cloth, to humans covered with leather, and then soft iron rings combined with the previous, on to much more iron and steel in mail and plate. As the target got harder the materials had to get stronger. The technology was driven by the need to continually meet these new demands, and defensive and offensive advances fed off from each other.

The arms race didn’t start after WWII, it started around 3,000 B.C.

Thank you Kevin! I just learned some history that places things into perspective.

Thank you for the insight Kevin. Great point about the arms race. Sword shapes also evolved to compete against the type of armor as did styles of fighting. In Europe that is. So much history to learn, thank you for adding to the education.

Brion

I am just finishing up readin "The Craft of the Japanese Sword". It mirrors the point Kevin made about the way the Japanese method of breaking up the refined bloom and redistributing the highs and lows of carbon content to put it right where it's needed most. That point struck me the most when considering the link above. That alone placed the Japanese on another level of sword making. The Japanese are a very disciplined people historically. This contributed to the preservation of the various elements of the craft. However, it's my belief that they were not acting merely on disciplined rituals. I believe they knew much more about the carbon and the way it affects the sword than is sometimes credited to them.

When looking at the tests on old swods and seeing the varying degrees of hardness and the fluctuating rockwell levels, I could not help but think that, as with now, there were just some makers back then who were not as good of makers as some others.

On the other hand there were many innovations in the west that put them on an entirely other level of swordmaking as well, but the due credit is yet another victim of the lack of information being passed down, and a very favorable spin of Japanese blades in modern pop culture. The one that blows me away are the levels the Chinese took swords, and metal working in general, long before the west or the Japanese even got started. By the time most other cultures were producing semi reliable steel, China had already forgotten more than they would know for another 500 years. From Viking swords made from crucible steel (yes wootz), to Chinese tools being mass produced by via industrial scale casting centuries before the birth of Christ, so many cultures did amazing things that were forgotten, the Japanese were very fortunate to have a good accounting and popularity in modern times.

In my view, the strict adherence to tradition and discipline is what provided the foundation and momentum to keep the craft alive and advancing.

Great information Kevin. I really think some of the makers back, say 1000-2000 years ago, could show us a few things. Same basic understanding, slightly different vernacular.

I think, in a way we are a victim of our own technology. Many would think that I am a technology junky, but that is not true at all; I often regret the crippling effect that technology has on the development of human skills. I am a knowledge/information junky ! Whether one is working with a hole in the ground filled with charcoal or dialing in an induction heater- knowledge is power, and the more you have the more you can do.

I have seen so many things done in ancient times that are beyond comprehension, simply because they dedicated themselves entirely to developing the necessary skills. We have not lost the ability to do these things but I believe our technology and modern conveniences have robbed us of that dedication. We look at the Pyramids and say it is impossible without arcane secrets (or alien technology <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//rolleyes.gi f' class='bbc_emoticon' alt=':rolleyes:' /> ), but it is only impossible to us because in our time we cannot image rolling up our sleeves and dedicating ourselves to a project that our children or grandchildren will have to finish after we spent our lives on it.

I feel it on a small scale in my shop. I very often find a little feature that I feel is not practically possible just because I cannot get it with the belt grinder or other power tool. But if I actually dedicate myself to doing it by hand I find that in a little time of training my hands to do it, it indeed can be done and often as quickly as it could have been done with power tools; I just had to lose the dependency on the modern conveniences. Some things are not possible without modern technology, others are merely conveniences, I think we can all benefit from recognizing the difference.

The ancients must have applied this to the acquisition of knowledge, they were pretty darned sharp because they had to be. They had to develop skills of observation because they didn’t have things like the internet. We have the advantage of all of their accumulated knowledge plus all that we have added to it, thus we would be the envy of the ancient smiths as much as we admire them. But now we must be careful not to let the convenience of information at our fingertips do the same thing to our knowledge building skills that has happened to our hand skills.

I think there is a dangerous habit we have, I know I have to correct myself all the time, of separating us from our ancestors, making it somewhat an “us vs. them” situation. When in fact we are them! It is not separate compartments of exclusive knowledge, but an unbroken line of accumulated, inclusive information, stretching from the past to the future. We ourselves are the ancients to those who will come after us and use the knowledge we pass on. Induction furnaces are not the opposite of a charcoal fire, they are what a charcoal fire becomes when industrious people work with it for over 2,000 years. O-1 is not the antithesis or death of bloomery steel, it is what bloomery steel becomes if you let crafty people play with it for many centuries.

At least that is how I see it. <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//wink.gi f' class='bbc_emoticon' alt=';)' />

Interesting information. The RC hardness levels do raise the question of whether some of these blades were hardened through a heat/quench process. Personally, I was wondering if some of the hardness data could be a result of work hardening the steel.

curious,

Dan

My link

Not much on Catalan Hearth but leads into...

My link

Catalan Hearth story... if the link doesn't work, copy/paste everything inside the " ".

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Still... widely varying carbon content, to no carbon content, to some varying carbon content wrapped around no carbon content (both with functional/artistic pattern welding) is making a sword that actually gets used. The Japanese seem to have always chosen to create an infinitesimal line, then proceed to walk along it.

Mike