katana grind

Status
Not open for further replies.
Richard338

Richard338

Gold Member
Joined
May 3, 2005
Messages
7,186
A question or request for suggestions about the cross section (basic grind) of a katana.
@stacy

I started grinding the bevels on my katana yesterday.
36" OAL, 27" blade, 3/16" CPM 3V, pure stock removal.
I had previously done the profiling and now started the bevels.
I started cautiously with an 80 grit belt, and tried sliding it across the rest for each pass.
This didn't work so well, and I ended up free-handing across the platen like an overgrown knife.
I also switched down to 36 grit and found it easier to be smooth while removing most of the material. After about an hour I got into a groove and felt pretty smooth. I haven't ruined anything yet.

I have seen some variations in the grind cross section and wonder which I should go after.
I have been working on a flat grind about 3/4 height. After HT I planned to convex it toward a zero edge. I also plan to have a peaked spine, like a shallow angled roof, that I see in most of the pictures.

My question is this: should I try to have a crisp transition between the bevel and the flat at 3/4 height (difficult to keep perfectly even down the length of the blade). Or should I blend that into a full-height convex. I have seen both in pictures. For me I think blending and convexing the whole thing would be a lot easier...
 
OK, some terminology may help:
The spine is the mune. If it is peaked like a roof, it is called ioni.
The transition (called a ridge line) where the upper half meets the bevels is the shinogi.
If you have a shinogi somewhere in the middle of the blade ( usually about 2/3 up from the edge), the blade is called shinogi zukuri.
If you have no shinogi, and the bevels go all the way up to the mune, then it is hira zukuri.
There are many names for the cross section of a blade, but the ones you describe are pumpkin seed and apple seed.

Now,
The biggest thing to get in your mind is to NEVER think of a katana as a big knife. All the geometry and shaping are different. If you grind it like a large knife you will be disappointed in both the look as well as performance.
If you have no experience making Japanese swords, don't try a shinogi zukuri. Do a convex full bevel - hira zukuri. After the bevels are done to 400 grit, add the peaked mune. Start the convex fat and reduce it toward the edge as you refine things.
In shaping the bevels, it is important to remember you can take more metal off if it ends up a bit fat … but you can't put any back on if the edge gets too thin.
 
Awesome as usual Stacy! (I'm over the ioni)
hira zukuri it is then...
To be clear, I'm not thinking of it as a large knife, I just meant that I got into a grinding rhythm with 27" passes that was quite unique in my experience (I thought grinding the kris dagger was tough...)
I'm taking this slow and hoping not to mess up. I will take my time planning all the parts of the handle. I will try to pick up some ray skin at ICCE.
 
Last edited:
Why shouldn't he try a Shinogi Zukuri, Stacy? Because you feel it is more difficult?

As to different "knife" grinds not working, I make a non-traditional grind Waki and have a client who is high ranking in a Japanese cutting martial art. He states that tatami mats run in fear. His Sensei, rather reluctantly agreed that it is one of the best cutters he's used.... but refused to let him test with it because in is non-traditional. Alas, that is anecdotal at best and if your goal is to make a traditional looking "Katana" by all means, stick to the plan. I ground mine like a different kind of knife and it seems to work. I went at it in facets, then blended them all in.... much the same way I make a knife. The plunges create a faux habaki.

Probably not the look you are going for but here is a pic to show my work.

2v2Jd5PjNxAhgEC.jpg
 
That looks great Rick. Yeah, I'm more worried about execution. Yours is probably more even than where mine would end up. We'll see...
 
I agree that Rick can pull of a stunning hollow grind katana, but as his friend found out, it won't be considered "right" by many folks.

A maker new to katana may have a lot of trouble keeping the shinogi straight. Starting on hira zukuri makes the first step of learning the shape and grinding/polishing of a blade. I should have phrased it, "A person new to Japanese blades my want to do hira zukuri first and shinogi zukuri after he has figured out the shaping of the blade."

I will also offer my thoughts on doing the shaping and finishing of a Japanese blade in shinogi zukuri.
It may be better to do only the basic stock removal on the belt grinder, and do the rest with files, sandpaper, and stones. Stuff goes wrong fast on a belt grinder. However, you can slowly sneak up on the perfect appleseed grind with files and blocks of wood wrapped around sandpaper. Once you learn to use water stones, they can do shaping really well.
Polishing is also something I find best by hand.
I use the flat platen followed by a rotary platen to get the shinogi pretty close to where I want it and sanded to 220 grit. From there it goes to the togi bench and hand work with wet sandpaper and stones. I find wet sanding works much better than dry sanding on blades like this.
 
It is a shallow convex. The polished edge appears to be a secondary bevel but it is full convex... just elongated. I only posted mine to address your statement that a knife-like grind won't perform. If you look into how a Katana cuts it's target, you will see that there are several ways to approach geometry and achieve the same end goal.

I think it would help Richard to see an example of your work, Stacy.
 
Last edited:
YES! Please use the correct terminology.....so that nobody has any clue what you are talking about save for sword smiths who think folding the steel a million times gives the blade some “magic” supernatural ability! Oh! And pretend you are Japanese while you are at it! Heck! Go ahead and call yourself a 17th, 18th, or 25th generation “KONICHIWA” Blade Smith!! Just so everyone knows you are super serious!:rolleyes:

LOL! You said the words GRIND, SPINE, BEVEL, FLAT GRIND, TRANSITION, & CROSS SECTION. And I understood EXACTLY what you were saying!
 
Guys, I'm happy to hear any opinions and suggestions. I did ask for Stacy's advice in my first post and he is generous to write a lot of details which have helped guide my plan. I won't memorize all the terminology, but I realize that I will come across a lot of it, especially as I move on to planning the handle parts. I'll be sure to post some pics once I make some progress.
 
One Armed said:
YES! Please use the correct terminology.....so that nobody has any clue what you are talking about save for sword smiths who think folding the steel a million times gives the blade some “magic” supernatural ability! Oh! And pretend you are Japanese while you are at it! Heck! Go ahead and call yourself a 17th, 18th, or 25th generation “KONICHIWA” Blade Smith!! Just so everyone knows you are super serious!:rolleyes:

LOL! You said the words GRIND, SPINE, BEVEL, FLAT GRIND, TRANSITION, & CROSS SECTION. And I understood EXACTLY what you were saying!
Click to expand...
BUT it is “magic” at least to me .As I understood @ Richard338 wants to make Japanese sword called Katana so Stacy give to him right guide with proper Japan terminology . ..I don t see whats the problem is with that ?
There is some magic in their terminology although I do not understand them and it's hard to remember them :)
 
LOL , yes I know. I was simply joking. It’s not my thing, although I may do a sword at some point. But I have no interest in learning and using the “correct” words. I like simple blade terminology. I just think some people take it WAY to far! To the point they even look down on others who DON’T use the Japanese terminology. CORRECTING someone over a word when you know exactly what they are talking about, is just...well, bad form!

The lavish folded steel blades forged by professional swordsmithe are beautiful. But if I wanted a sword, it would be done sane as the OP. A CPM3V sword made via stock removal will destroy any forged sword ever made. Period! I really don’t care about the “correct” word of a component.
 
One Armed said:
The lavish folded steel blades forged by professional swordsmithe are beautiful. But if I wanted a sword, it would be done sane as the OP. A CPM3V sword made via stock removal will destroy any forged sword ever made. Period! I really don’t care about the “correct” word of a component.
Click to expand...
It is not proper place for this kind of discussion but let me tell you something .Maybe your CPM3V sword will destroy old Japanese Katana but ......Your blade worth ... how much ? 1000 , 2000 dollars ? Do you know how much worth original Katana :p
PS . It is much easier to make this Katana in OUR way ....be my guest and try to make Katana in old fashioned way , can you ? I don t think so :)
 
Last edited:
Natlek said:
It is not proper place for this kind of discussion but let me tell you something .Maybe your CPM3V sword will destroy old Japanese Katana but ......Your blade worth ... how much ? 1000 , 2000 dollars ? Do you know how much worth original Katana :p
PS . It is much easier to make this Katana in OUR way ....be my guest and try to make Katana in old fashioned way , can you ? I don t think so :)
Click to expand...


I agree. Which is why I said they are absolutly beautiful! (Miss that did ya?) And cost is a moot point. I care about performance, not what someone will pay for it. Lastly....YES! It would be almost impossible for me to forge a folded steel sword or blade....or to forge ANYTHING really... It would be a little awkward trying to hold the tongs and swing a hammer using my ONE ARM/HAND!
 
Last edited:
Speaking for myself:
I really don't care if you have a problem with my advice - it wasn't given to you. I think Rick and I are fine with each other looking at it from different sides of the issue.


Speaking as moderator:
I don't know what you are so angry about, but this forum isn't the place to vent it. If you don't have something useful and constructive to add to the OP's question, please don't post at all.
 
With all of this talk and advice about Katanas, Stacy how about posting a pict of one of your katanas?

We all would love to see it.
 
I'm actually making a katana for a client currently. Its going to be very simple. Not even remotely traditional though.

It will likely have G10 or micarta handle scales and is being designed for somewhat hard use. Likely wood and other materials, maybe tatami mats, but not likely.

My issue is I dont know what edge thickness to use. It currently is full convex ground and I will likely thin the edge more before sending it to Peter's. The steel is CPM 3V.
26 inch blade, 10 inch handle, very small integral guards. Aiming for 59/60HRC for maximum toughness. 0.220 thick stock. Tapering down to near 0.187 near the tip. Stock removal only.

Also I'm still trying to learn the terminology for katanas and Japanese blades. Most of what was said went over my head
(with all due respect, only been making for 5 years)
 
ShannonSteelLabs said:
I'm actually making a katana for a client currently. Its going to be very simple. Not even remotely traditional though.

It will likely have G10 or micarta handle scales and is being designed for somewhat hard use. Likely wood and other materials, maybe tatami mats, but not likely.

My issue is I dont know what edge thickness to use. It currently is full convex ground and I will likely thin the edge more before sending it to Peter's. The steel is CPM 3V.
26 inch blade, 10 inch handle, very small integral guards. Aiming for 59/60HRC for maximum toughness. 0.220 thick stock. Tapering down to near 0.187 near the tip. Stock removal only.

Also I'm still trying to learn the terminology for katanas and Japanese blades. Most of what was said went over my head
(with all due respect, only been making for 5 years)
Click to expand...

Please post some pics as it progresses.
I finished most of the pre-HT grind last night leaving some for post-HT (hopefully to help avoid warping).
As it gets closer to its final weight, I'm getting excited about cutting with it. (feels pretty light)
I also got some helpful advice from Matt Gregory about terotuf handle construction that I will cover with ray-skin and wrap.
 
I suggest leaving a fairly good edge width ... about .030" ... before HT.

If I understand your term "very small integral guards", they are called machi (notches) the one at the edge is the ha-machi ( edge notch), and the one at the spine is the mune-machi (spine notch). The habaki and tsuba seat against them.
 
Status
Not open for further replies.
Back
Top