bending a katana (and steel choice)

[Andrew Garrett]

I've hooked a good friend on the idea of blade making (poor bastard). He's into Bushido and has taught for many years, so his primary goal is to make raditional katanas and tantos for his students.

I'm sharing my limited knowledge and all my books and resources with him as we discuss a plan of attack for him to tool up and get to work.

My (our) first question is steel choice. I'm wanting to suggest 5160 for combat quality katanas that will actually be used several times a week during house's training. These aren't to be wall hangers. I like this steel for it's availabilty, toughness, easy HT and ability to reveal a hamon.

My second question is about giving the sword it's arc. Commit to forging a bevel which will bive it some bend, or can it be heated and bent over a form without stressing the steel where the edge will be? I have a feeling I'm gonna hear "forge it!" from more than one of the experts here, but I wanted to give him some options. Remember, These will see real world use in cutting exersizes and steel on steel training.

Target hardnesses will be around 58 on the edge and 40ish on the spine. Sound good?

[ONT]

I just received Walley Hayes video for a stock removel katana. It looks a very good video. I'm looking forward to trying this project.

[Ray Rogers]

I'm not an expert on swords per se but I have seen them made and I've made some fairly long blades myself. The part of your question that I am addressing is how the curve gets into the blade. generally, forging in the curve is not necessary.

You said you want a hamon, therefore you will be clay coating your blade, which also achieves the soft back that you desire. When you forge a blade bevel it takes considerable practice to PREVENT the blade from curving. It will probably curve more than you desire. Once you have forged (or even if you grind in the bevel) you have a straight blade to which you will apply the clay. When you heat the clay coated blade and quench it the difference in the cooling rate between the coated and uncoated portions of the blade will cause the curvature that you see in real hand made katanas .....

[Frank J Warner]

Boy, Andrew. Learning to make a Katana can take a lifetime, so you're only going to be able to scratch the surface here.

But, just to respond to two of your questions, I would stay away from 5160. My information indicates that it won't give the kind of hamon you'd be looking for on a Katana. A better choice would be one of the 10xx steels, 1085 or 1095.

And, the curve in a Katana is actually a result of the various heating and cooling cycles during manufacture. Clay-coating the mune and leaving the ha bare during heat treat, which gives the hamon (in Japanese, "hamon" means "edge-flower") sets up differential expansion and contraction in the steel that causes the traditional curve. Katanas are not simply bent, but start off as straight billets that are allowed to curve naturally as the steel goes through its various hardening transformations.

From http://www.galatia.com/~fer/sword/term.html :
Yaki-ire The hardening of the steel by heating and quenching in water. The cutting edge of the blade has a thin coat of clay while the rest of the sword has a thick coating of clay. When steel is heated to between 700 C to 900 C the crystalline steel changes to the structure called austentite. When it is cooled quickly, where there is thin clay, it changes to martensite. The rest of the steel cools slowly enough that it changes back to it's original ferrite or pearlite forms. The blade also gets most of it's curvature due to the differential expansion of the thin edge and the thicker back of the blade.

-Frank

[AUBE]

i have yet to make a sword, just read about them and made some large knives.

i vote for 1070 steel.

do you plan on water or oil quenching? water will create the backwards curve but can also be a pain in the butt (warping, cracking) if you dont have everything exactly right. if you arent used to water quenching i would recommend trying it on at least a few knives before committing to a sword. quenching in oil will cause the tip to curve slightly downward like a sicle(spelling?)..or at least it always has on my oil hardened blades

[fitzo]

I would second ONT's recommendation of Wally Hayes videos "Modern Katana". Yes, he's an ABS MS, but this is a stock removal approach to making a modern interpretation of a katana using 1050-1075. It is worth the heat treating sequence alone, not to mention the excellent tutorial on handle wrapping and Turkshead knot tying.

This is a must see for an interested maker that doesn't have access to a swordmaking teacher. It will be money well spent just in time saved in the learning process and the value will be recovered in failure reduction.

[AcridSaint]

I'll vote for 10xx steel as well, Scott Slobodian swears by 1050, I would say 60 or 70 is just fine too. 1095 will have a better chance of cracking. You want a shallow hardening steel to get a nice hamon. W-1 or W-2 are also reported to work well, but I've never had a chance to see them. Of course, forward your friend along to the Engnath site, www.engnath.com, Bob made many great Japanese style blades and left lots of useful info.

[Don Halter]

I like the 1065 I got from Kelly Cupples. It's a nice starting size for Japanese blades. I also like using W1 drill rod in 5/8" dia. If you use W1 or W2, it can be unforgiving in even a slightly botched heat treat. Both will give really nice hamon. I water quench these. I have also used oil hardening steels. And yes, you can get a hamon on these...just not usually very dramatic.

I have some info on my site here:
http://www.100megsfree3.com/kragaxe/.../Japanese.html

It hasn't been updated in quite a while, but has a few good before/after shots of tantos.

[Drac]

Angel Forge not only makes katana sets but the owner is a matial artist as well. He also teaches people, intern style. Might be something to look into?

Jim

[Andrew Garrett]

Lots of info guys, thanks!

I was leaning toward the 5160 based on articles in Goddard's book where someone asked him a similar question. The need here is for strength in a steel-on-steel impact. These swords won't be babied at all. But, you guys say 1060-1070 or so, so be it.

I'll suggest the video and maybe even buy it myself just because his interest has sparked the same in me. Sounds like a challenge! I also found a place online to rent that and many other instructional videos--pretty cool really!

Thanks again fellas! As usual, I need look no further than TKN to get all the info I need! This place rocks!

[McAhron]

L6 is a popular choice for combat katanas.1050-1095,or w2 for hamon.You can put the curve into the steel without forging it by heating and bending around a form,die anvil,or other fixture.If you water quench it will naturely rise tip up,but in oil it will bend down.There are several videos on the subject as well as books.Don Foggs site sells several.Good luck on you endeavor.

[howiesatwork]

Andrew, you mention steel-on-steel impact.
Katanas are not designed for sword fighting, but cutting.
A steel-on-steel strike will result either in a chipped edge, a bent katana, or a broken katana with parts flying... not good.

[Andrew Garrett]

There is a japanese word for the steel-on-steel training technique and it is common in bushido exersizes. Maybe Tora (my buddy whom I'm researching with) can wiegh in here since I know he's been reading the forums lately. I guess the strikes are side on side rather than edge on edge. I think this training is meant to pratice blade angles.

As a further note, NO SWORD with a full length edge is designed to strike against another sword. They are built for hacking flesh. Only a fencing foil (which is a training blade for rapier combat) is so designed. However, all sword training includes defensive techniques which means... steel-on-steel. Thanks for pointing that out though.

[Raymond Johnson]

Ok here goes my two cents. If you can live without the hamon, then I would suggest S-7. It is one of the highest shock resistent steels out there, will harden high enough for knives, is air hardening, can be sent out for heat-treatment, and can be found in sizes you will need. Next L-6 but don't hard to quick, look it up. I know some will disagree, but you ask my opinion. As for the hamon I have done many and I suggest a lot of practice on tanto and wakizashi frist. Keep notes and look at the chemical composition of the steel your using and learn what the elements do.
Good Luck Raymond Johnson

[hammerdownnow]

Here is a youTube video on quickie katanas. I like those anvils.
http://www.youtube.com/watch?v=B_JcP...search=forging