Sword Edge Tempering

D

DPris

Joined
Nov 27, 2003
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I know how the khukuris are done, but it seems an awful hard way to get an even hardness temper along a much longer straight sword blade edge.

Anybody know how it's done on the HI swords?
Denis
 
When I asked the same, I was told they are hardened (let's use the proper term :P) pretty much along the edge, and some pictures I've seen with acid etching support this. Ok, maybe the tip and the very end of the blade entering the handle may be left as springs.

But there are people that know more than I do around here, I'll let them chime in.
 
That'd be difficult to do in pouring enough water from a teapot & making sure it hits widely enough all along the edge.
Denis
 
DPris said:
That'd be difficult to do in pouring enough water from a teapot & making sure it hits widely enough all along the edge.
Denis
Click to expand...
Not if you had 40+ years of practice;)

Wouldnt you love to watch them do it tho?
 
I'd very much love to be able to be there & watch all the processes live & in color. :)
Denis
 
I thought I had read somewhere that there is like 15 color changes in a specific order when the kamis temper the blades...pretty cool.
 
the kamis differentially HARDEN the blades (zone hardening) with their teapots & boiling water. this hardens the edge/sweet spot where it is quenched by the water. the areas not in contact with water cool at a different rate and the hardness drops off the further you get from the quenched area, the residual heat self tempers the knife.

this video is fairly good at explaining the difference between hardening & tempering. as he notes, knives are a bit more complex than a simple hardening/tempering cycle.

[video=youtube;3CnwUQZ6q78]https://www.youtube.com/watch?v=3CnwUQZ6q78[/video]

here's a guy differentially hardening a blade with a torch, heating to red then cooling the edge quickly in a trough of water, followed by a quick tempering pass with the torch again. this is more similar to the kamis method.

[video=youtube;DM7STNHEMlY]https://www.youtube.com/watch?v=DM7STNHEMlY[/video]
 
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I'm familiar with the khukuri method, I'm saying I think it'd be extremely hard to transfer that to a blade edge that's much longer & more linear on a sword, by just pouring water along the cutting edge from a teapot.

Do they use a trough?
Denis
 
Nice explanation. Thing is, sometimes the terms are used interchangeably, I correct myself every now and then as well.
 
I did some excavating in the HI archives and found some information about how they were heat treating their swords, plus some impressions of the first Everest Katanas:


03-12-2000, Bill Martino
I was worried about the heat treat and still am -- reason I was playing with the transmission oil.
Our solution at this stage is to put two fans into one forge so the entire length can be heated at once. If they do this I am reasonably confident the hardening process using the slow water quench will give us what we want and repeatability should be good. But, we'll wait and see...

03-15-2000, Bill Martino
Kumar is having problems getting the blade on the katana hardened the way we want it -- this was my greatest fear about this project and the reason I was trying to use transmission oil as a que4nching medium. Bura will try his hand at the hardening and we will see what happens.
Maybe I have asked the kamis to stretch too far. It is a long shot from an 18 inch AK to a katana. The bottom line is if BirGorkha cannot produce a katana of outstanding quality, a quality that equals our khukuris, then the katana is a dead project. HI refuses to offer any blade that is not top quality.

http://www.bladeforums.com/forums/showthread.php/126511-BirGorkha-Everest-Katana-prototype-is-here-Pix-specs-and-evaluation


05-16-2000, Broken Arrow
Everest Katana #2, test and review
Well, guys I have done a complete ferric chloride etch and a complete polish. The etch showed me a hamon on this blade, 1/4" from the tip (3" from the tip) and gets thicker at 5/16" almost all the way to the handle. There is a 3.5" section in front of the handle that doesn't have the hamon. One thing that the etch tell me, is that this sword has a good hardened edge. It could be more consistent, but this sword is meant for actual use, and not an art object. I did a complete polish on it and the hamon really stands out. Nice to look at.
I was able to do some more cuts with the new edge and once again , no rolled edges or nicks. I also did some thrusting with this sword. No problems. So far so good. Some of the targets I used are not usually used in traditional sword testing (tree branches 2"-2.5", plastic garbage cans, rolled up shotgun news, and PVC pipes 1" thick), but I know many people will use what ever they can in their own tests. This sword has withstood some of my tests so far and it is passing with flying colors! No damage or looseness has occured to this Everest Kat #2 so far...

http://www.bladeforums.com/forums/showthread.php/146671-Everest-Katana-2-test-and-review


08-03-2000, Bill Martino
The katanas continue to improve. Broken Arrow did an acid etch on the katana he tested and I think this one ended up with Harry. The hamon was perfectly acceptable and the sword cut through the spine of a cow (more than once, I think)and completed a program of severe testing and when I got the it back I could not tell that it had ever been used.
The quality is improving with each shipment but they are toying with the design and that has got to stop. They are supplying a different design each time -- little different tsuba, different handle, different scabbard. We have got to make a stand at some point and I think we are there.
The tsuba is steel and is beautifully engraved on blade side.

08-04-2000, Broken Arrow
Wow, the Everest Katanas are looking good with each sword. For a blade this long a proper heat treatment is esential. The prototype #2 that Harry has, is a good sword. The heat treatment was good, but could be improved. Not bad for #2 though. When I did an acid etch on the blade, I was able to see the actual hardened area. The tip area was somewhat thin, but hard. 3" from the tip (kissaki) the hamon was over .25" thick and this tapered off 2" from the tsuba (guard). While not perfect in the eyes of a traditional katana collector, the blade did withstand my testing. The bone test that I did surprised me. Better than I expected...

http://www.bladeforums.com/forums/showthread.php/147094-I-have-this-katana-I-am-going-to-call-a-blem/page3


01-01-2001, Bill Martino
As I have mentioned before the Everest Katana is NOT a clone of a Japanese model but an effort by men who believe the first function of any knife is to stand up to hard use -- second, if it can be made beautiful in addition to strength and toughness OK. But beauty, tradition, everything will be sacrificed for function.
This is why our katana has a handle that will not fail and a very tough but sometimes not so traditional blade.

http://www.bladeforums.com/forums/showthread.php/157303-Everest-Katana-thoughts-wanted



After the Everest Kothimoda Katana arrived:

01-19-2001, Bill Martino
I got personal email from a swordsman who saw these pix and he said "you are selling a $5000 custom sword for $500." This man already has a katana and a tarwar of his own so he is speaking from personal experience and not just the pix.

01-19-2001, rdnzl
I took it to work with me today. Everyone I showed it too was very impressed. I never said what it cost, I just let them speculate on their own. I had a couple guys say it had to cost at least $2000. I just let them think that for now. I told them the tale of the kamis of Nepal, and one guy refused to believe the Katana itself was made by hand by one man using basic tools and a hand fired forge. He thought there was no way it could be made this straight and true by hand.
One guy even has some expensive swords at home, and he said he liked the EKK better, that it looked more "crafted" than "produced".

http://www.bladeforums.com/forums/showthread.php/157402-Some-EKK-Pics
 
Thanks a bunch for compiling that Steve. Several hours later;) Interesting reading the evolution of the Katana. Makes me want to go take all my swords out to play. Im thinking what fun it must be to harden the Manjushree? Like hardening two Katanas at once. Truely amazing.
 
Well gee thanks Steve, now I want one of the HI Katanas. And of course a Wajaski, just because I like the idea of the Wakizashi to begin with.
 
Everest Kothimoda Katana by Rajkumar, turquoise and coral sheath by Arjun, and Wajisaki Katana by Yuvraj.

331d962f12bddbf1c54741ab5fa025a5


6f8c3a2c7c7afdc9ccc8f58604f88e2d


Rajkumar

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Yuvraj Wajisaki with tsuba and carved habaki.
 
Probably belongs in this thread:

02-23-2000, Bill Martino
When I described how the Japanese sworkmakers use a mud wrap during the hardening process the kamis were not in the least surprised and answered, "sometimes we use that method ourselves."


02-23-2000, Jim March
A bit of history here:
Three or four years ago I was shopping for a sword blade I could mount up myself and make a fairly basic RenFaire carry piece, practice sword and maybe get into SCA bottle-chop competition. So I wanted "battle ready", something real versus some Taiwanese stainless horror.
At a local gun show, this guy was selling old Japanese swords. I bought one he claimed was early 20-century Japanese, what's known as a "Gunto". Cool. About a year later, still hadn't mounted it yet (sigh) and I show it to a friend who'd spent time in Japan and knew old swords.
The city of origin was Kyoto - except one little problem...it was the character as it was used prior to 1864 and the fall of the Shogun.
Most likely date is near 1830ish, give or take.
Another year goes by, and an evil roomie *steals* it. Grrr. I get it back a year later, he was an idiot (we knew that) and left it tip-down in a closet so the last 3mm or so of tip rusted.
It could still be polished out just fine, but it'd need a traditional polish and re-scabbard job running $800+, and new furniture running another $650 minimum. And then it'd be a "pure wall-hanger" because of age and value up around $2000.
Welll...I didn't want a wall-hanger anyways.
So here's a better idea: it now hangs in BirGhorka's shop wall! I get the battle-ready practice sword I wanted in the first place, and HI gets a new product...
Bill will price 'em but we already know that the Paul Chen "Practical Katana" is junk at $150ish and it ain't until you spend $450ish that you get anything worthwhile from him. The HI version will be far better steel than Chen's railroad-tracks, and there will be details of balance and blade design complexity copied off of that true original Edo-period piece that ain't found in anything Chen makes at any price.
I figure the HI Katana has got to be worth $350 to $450. It'll be the toughest critter in anything remotely like the price range.

http://www.bladeforums.com/forums/showthread.php/126439-The-first-secret-project-the-BirGorkhka-Everest-katana-Pix
 
Stop posting fascinating and cool stories about the HI Katana, Steve. I can't afford to buy yet another blade. Not yet at least. ;)
 
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