Met lab analysis of samurai sword

I have a WWII Japanese sword from my granddad. One of three he brought back from Pacific theatre. Its in rough shape cause he didn't store it correctly. I will confirm though it is not a "Samurai" sword it was definitely made in a factory. still cool though .
 
don't know exactly what kind of sword was tested, the army used the term "Samurai Sword". if the photos were better we might be able to tell more.
 
scott.livesey said:
found this in my travels. a US Army lab analysis of a captured samurai sword
http://www.dtic.mil/dtic/tr/fulltext/u2/b962712.pdf
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I wonder what sword they examined. The fact that it says the sword was air cooled after forging makes me wonder if it was a ww2 era Japanese sword. The date on the study says 1997.

I was under the impression that traditional nihon-to were water cooled with differential thickness of clay applied in order to give them their characteristic curve.
 
Lapedog said:
I wonder what sword they examined. The fact that it says the sword was air cooled after forging makes me wonder if it was a ww2 era Japanese sword. The date on the study says 1997.

I was under the impression that traditional nihon-to were water cooled with differential thickness of clay applied in order to give them their characteristic curve.
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25 sept 46 was study report date . The later date was date of release for public ?
 
Actually now that I’ve read the study it appears that alot of their findings were due to misunderstandings about japanese sword production.

Their hardness tests were all done at the back edge (spine) side of the sword which is meant to be softer in a differentially hardened sword.

There were other errors I noted like the belief that the hamon was produced using a flame hardening technique. (They note it could have been produced by other methods, and it likely was)
 
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My WW2 era Japanese officer sword has no Hamon. some had markings under the handle on the tang, as the war continued and things got worse for them they no longer even marked the tang . quality went down hill also. from my research not many took their prized family heirloom swords into battle. the risk of losing them was to great . Mine is not really even sharp. there are a couple nicks in the edge but that could be from my grandfathers sons finding the sword as children and messing around with it.
 
Lapedog said:
Actually now that I’ve read the study it appears that alot of their findings were due to misunderstandings about japanese sword production.
Their hardness tests were all done at the back edge (spine) side of the sword which is meant to be softer in a differentially hardened sword. There were other errors I noted like the belief that the hamon was produced using a flame hardening technique. (They note it could have been produced by other methods, and it likely was)
Click to expand...
if you look in the data section of article, they did vickers testing on the cross sections they took out. highest readings for edge was in the Rc50-52 range.
 
The measured composition looks suspiciously like factory produced steel rather than tamahagane.
 
I would recommend reading this. It is a perfectly enjoyable book with terrific color photographs of the process. :thumbsup:
Here is an interesting one : Old pre war anchor chains are preferred for the iron because it tends to have impurities that the stones like and it helps condition the stones while sharpening the sword. Some one here clarified that for me one time but it would take a while to look up the "nitty gritty" of it (sorry couldn't help it).
517HnzP7RdL._SX364_BO1,204,203,200_.jpg
 
This is definitely not a high quality sword. Almost assuredly one of the mass produced officer's katanas. I have reservations about how the testing was done also... They only tested hardness near the spine before cutting the sword up. As I'm sure we are all aware, this is the softest part of a katana. They only checked nearer the edge after cutting the sword apart. Back in this era it would be very difficult to section (cut) the sword without ruining the temper and making it softer, so IMO those tests are very likely invalid, with meaningless results. Especially since the method of sectioning wasn't detailed. The Japanese were/are not idiots, and I would find it shockingly incompetent to let a katana go out the door of the factory with hardness as low as the mid-40's Rc at the edge. Notice that after they sectioned and checked hardness, they quenched the sections and rechecked hardness and achieved 64Rc.
 
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