tanto

Bradley Lee

Bradley Lee

Joined
May 8, 2014
Messages
45
the shape of a 20" overall tanto blade. 7.5 handle, 12.5 hira-zukuri blade. What percentage of blade tapper and width at base to blade end?
 
Bradley,
You have the same question posted on the thread right below this one. Neither thread is likely to get much of an answer.

You are eager, and want to learn. That is good. However, your method for the last six months has been to ask a short and very broad question that shows you did no research at all. There is no simple answer to very broad questions. We are all here to help people learn, but they have to do part of the work themselves. When asking most forum type questions, ask yourself, "Can this be answered in a few simple sentences?" If not, take a look at the question and try to refine the scope or do some more research.

HT for several different steels is more than just a simple question, as is bushcraft styles, ....and Japanese knife/sword shapes and styles.

My advice is to take some time and do some reading. Start with the stickys, they contain a lot of good info. Read all of them...maybe twice. Then, use the BF search engine ( found in the stickys) and look up tanto discussions and build threads. Next, go online and look at photos of tanto. You will see that there are literally hundreds of possibilities for shaping one. The final steps would be to plan out your build, make drawings, post them here, and get feedback on your build plans and drawing details.

You are just starting, and ambitious projects like Japanese blades are probably best for after you master the basics.
 
BTW, at 20" long with 12.5" blade it would be called a wakizashi. It could be described as O-tanto or shoto-wakizashi but once past 16" OAL it would generally be considered wakizashi.

Blade edge length:
Up to 12" - tanto
12-24" - wakizashi
24-36" katana
 
Hire Waskizashi.jpg With a over all length of 20.5" I am wondering what the tang should be. Thinking that a 6.5 would do, which would leave me a 14" blade length with a 13"cutting edge
.
 
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The nakago on a wakijashi isn't full length.

A 6.5" of nakago would support a 9-10" tsuka quite well, so the wak would end up around 23-24"
 
I would like to give as much as possible to the blade length. would a 7" tsuka work for this length? 4" nakago would give me a 15.5 cutting edge--- 23.5 over all.
 
Bradley,
I'm not sure what you want to make? You started wanting a tanto with a 20" OAL with a 12.5" blade edge. Then it became 20.5" OAL with 14" blade with 13" cutting edge. Now it is 23.5" and a 15.5" cutting edge.

Cutting edge is not the same as the total edge length on a Japanese sword. The cutting edge on a Japanese sword is a complex thing. It has different areas, and no one worries about the "cutting edge" length. You have the kissaki area, and the habaki, which both use up some of the total edge area. What is used to refer to it is the nagasa, which is the length from the mune machi to the kissaki.

A 7" tsuka is about as short as I would go on a 24"OAL wakizashi, but it would be OK.
4" of nakago would be the very minimum, and you should be a rather good at fitting nakago to tsuka for it to be strong enough. 15" of nagasa will be a quite sufficient cutting edge for any task a wakizashi would need.

I assume you are working from a bar of steel and are trying to fit the dimensions in the length you have. Take the total length of the bar, mark off the nakago part, and the rest is the nagasa....its that simple.

From your numbers, the bar is either 20" or 20.5". Lets call it 20". The nakago should be at least 5" for a 7" tsuka ( you need steel under the hand in cutting). That leaves 15" for the blade edge part ( nagasa). The first 1" from the machi will be the habaki, and the rest cutting edge. The last 1" to 3" will be the kissaki. I prefer to let the kissaki develop last, as it may change in your mind as you shape the blade. The kissaki shape in your sketch is a good one.

So:
5" nakago
15" nagasa
7" tsuka
22" OAL kissaki to kashira ( actually a tad longer, as the Koshirae add about 1/4" or so)

This will be a very impressive wakizashi!
 
I got my order in from NJ Steel Barron --- 1095: 1/4 x 1 1/4 x 48 for the wakizashi and 1/8 x 3 x 48 for some chief knives. Do not have the Parks 50 yet, so tried the 1/8" chief Knife in canola oil. 10 min @ 1100 then 1475 for 10min. Clayed up for a hamon. Got it 50 HRC on cutting edge and 30 HRC on spin back. Put it in for 2 hrs @ 400 and will see what it is. I thing it is not hard enough. Thinking I will have to wait on the Parks 50 and redo it.
 
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Who did the testing? Those are really low readings, even for 1095 and canola. Did the edge skate a file as quenched?

I forget, are you using a HT oven?
 
the first thing I did is put a file on the knife edge. It was biting into the blade pretty good so I put it in the hardness tester. Very bummed out about the results. Using a even heat KF 22,5 oven. The oil was one gal @ 120*F
 
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It's possible that you are dealing with decarb. Plus you say edge testing. Are you testing on a flat spot on the tang?
With a 20 minute soak I'm betting on decarb.
 
I agree with Brian. Try grinding a flat place on the tang and testing there. Grind a good ten thousandth off to be sure you are testing hard steel, not decarb. You have to test a clean flat spot with parallel top/bottom sides.

I would also grind down the edge a bit. Give it a pass or two on a 120 grit belt and see if it suddenly becomes hard.

Assuming something isn't wrong with the TC in the oven or Rockwell tester readings, the RC hardness should be much higher. As-quenched should be in the Rc65-66 area and after the 400F tempers, Rc62. Even if things were a fair bit off, these should only drop a few points for 1095.

Why did you use a 10 minute pre-soak at 1100F? I have not seen that recommended anywhere. A few people pre-heat the oven to 1100F and place the blades in, then ramp the blades from 1100F to 1475F at 9999. I think most folks just pre-heat the oven to 1475F, and place the blades in at 1475F. Once the temp returns to 1475F, you start the 10 minute timer. Remove and immediately quench in warm canola or room temp #50.
 
I was checking the blade with the hardness tester below and above the hamon , which is on the blade bevel. Checking the hardness tester and found the anvil lose. Will try again when I get some more time.
 
It is nearly impossible to get a good reading on the bevel. The hardness above the hamon will be quite low, since it is pearlite. The hardness below the hamon should be able to skate a file all day long.

On a blade with a FFG and no ricasso, it is good to leave most of the tang unclayed. That will give you a flat spot to test. You can always draw it back soft with a torch later if you don't want the a hard tang.
 
1095 chief knife.jpg I plan to take some of the same bar stock and grind it flat a different thicknesses and put it through the same HT I did the blade so I can get a hardness readying.
 
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