Fitting a Habaki

F

Fumblefinger

Joined
Dec 1, 2021
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17
Greetings all, first post.

Years ago I bought a cheap, bare iaito blade, not realizing how custom fit all the parts were. So, it sat in the closet for years. I have made wooden martial arts weapons for some time. I finally decided that if I could fabricate a habaki, I'd take it to the next step.

Things are progressing well, however the shinogi is wider in the nakago than where the habaki will sit. This makes it impossible to slide it over the "bump" to check fit without deforming the habaki. The only solution I see is to file the nakago to the same dimension as it is further forward. Again, it's a cheap blade, so it's not like i'd be ruining a National Treasure. I'm just curious if this is a common issue, or something on the inexpensive blade. Thoughts?

Thanks in advance.
 
The nakago has to be slightly tapered from the habaki to the nakago-jiri. Your nakago is unfinished. File/grind/stone it down as needed. I see them without machi, too. There needs to be at least a small machi on the ha and mune.
 
Thanks for the reply.
Stacey, I knew a taper had to be the case. But I see so many pics of nakago that have that "raw" look like mine, I wasn't sure how to proceed. This may have been why the blade was sold the way it was. Considered a bad job, let someone else fix it.
I'll get it filed down today and get this project moving.
Here's where I'm at.

https://imgur.com/a/YsOm6uI
 
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File it at the same bevels as the ha and ji. This carries the shinogi down the nakago. The taper does not need to be severe, but you want about 25% taper in thickness between the machi and nakago-jiri.
 
Stacy E. Apelt - Bladesmith said:
The nakago has to be slightly tapered from the habaki to the nakago-jiri. Your nakago is unfinished. File/grind/stone it down as needed. I see them without machi, too. There needs to be at least a small machi on the ha and mune.
Click to expand...

Stacy E. Apelt - Bladesmith said:
File it at the same bevels as the ha and ji. This carries the shinogi down the nakago. The taper does not need to be severe, but you want about 25% taper in thickness between the machi and nakago-jiri.
Click to expand...
Thanks again. I'll try to maintain the bevels.
 
Be sure to anneal your copper as you go, it work hardens and will make it much harder.
 
Thanks Adam, I've been doing that fairly often.
The research I did before I started indicated that annealing copper happens at 375-750F. I have a MAPP gas torch that is supposed to produce a 3700 degree F flame. This should be more than enough, and it seems to work fine. I don't get the cherry red color on the copper that I see in the videos, however. When I solder it I'll probably use my MAPP/O2 torch. It is supposed to produce a 5300F flame. The nice thing is that it is shaped just like a wood pencil, do it's easier to direct.
Ill post some progress pics as I go further.
 
I think you have the wrong temperatures.
Copper anneals by heating to dull red (1100-1200F) and quenching immediately in water. Heating to 750F and holding for a couple hours is how to harden copper.
 
I went back and searched for annealing temps again. I found everything from 572F to 1200F. But as I said earlier, the MAPP torch is supposed to reach 3700F. Surely that would be sufficient to get the chunk of copper up to the necessary temp wouldn't it? Would overheating negate the effect?
 
You don't need to heat it beyond dull red. The torch will work fine, just turn it down a tad.

Don't let sales hype fool you. The torch won't heat things to 3700°F. Heck, I saw one add that said its Mapp gas torches would heat to 5300°F. The theoretical temperature and what the torch produces are not the same thing.
 
Without a doubt that torch wouldn't meet max temp. It's basically designed for plumbing work with a "swirled" flame. Read circular, as opposed to pointed.

The nakago filing went well. I had to open things back up a bit to rework the munemachi area. But the notch is fitting nicely. Now I have to close it back up and get a spacer made for the ha side. Because the hamachi is forward of the munemachi, I won't have to fiddle with a notched spacer. The forward edge of the habaki will nest into it. I just have to make one to match the angle of the nakago.

In spite of the issues so far, I'm happy with how well the first attempt is going. Thank you all for your help.

https://imgur.com/a/BfWnHZS
 
The triangular wedge that closes the ha side is called the machigane (notch metal).

It looks like you added a piece of metal at the munemachi. I usually just fold the annealed metal (copper or silver) and use a brass hammer to shape it to a snug fit. Once shaped to the angle of the shinogi, I add the machigane to close the ha.

TIP:
Use an oversize piece of machigane to close the ha. It should go a tad farther than desired inside the habaki, and extend a bit past the habaki at the ha, as well as project past the front and back of the habaki.
After the brazing (hard silver solder), file the inside with a small square file to get a perfect fit. Then file away the excess sticking out past the ha and sides. This will give a perfect joint with no solder lines and allow a snug fit.

Nothing says poor workmanship like a rattling habaki!!!
 
Umm, nothing was added. Here is what I started with.
https://imgur.com/a/uh89DcX
It was hammered down over a piece of steel. Stupidly I made the tool the same thickness as the munemachi. So I made another with a bit of a taper to account for the radius in the forming, and used it to draw down the edges. I guess maybe what you're seeing are the indentations from the holding fixture (vise) as I hammered it from the inside to help close it up a bit.
https://imgur.com/a/LVzqSnw
Your suggestion for the machigane is basically what I had in mind. After looking at several methods, this made the most sense and the least amount of work.
"Nothing says poor workmanship like a rattling habaki!!!"
I absolutely agree! I mean a loose habaki negates it's purpose. I figure there is a lot of filing in my future...
 
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Filing, and gentle tapping with a small brass hammer.

I saw the line and color difference along the mune part of the habaki and it looked like an added piece. Your procedure is roughly what I use. One big requirement is that the copper be freshly annealed and re-annealed as often as needed.

More Tips:
Make a mock-up of a nakago out of any type of carbon steel laying around the shop. Make it tapered in all dimensions of the actual blade nakago. Harden it and temper at 500-600°F. Use this to work a habaki to shape. Once it is getting about an inch (25mm) shy of fitting on the blade nakago, move to the actual blade nakago and finish with gentle taps and some filing. This procedure also helps if you are hammer texturing the habaki, as the habaki grows in size due to the hammering. In hammered habaki, you want to leave the machigane for last so the habaki doesn't end up very loose. I usually braze the ends together at the ha and work the habaki, then cut off the excess and add the machigane.

To get a wonderful silver-black look like old shakudo koshirae, soak the copper fitting (habaki, fuchi, kashira, menuki) in a strong solution of Livers of Sulfur. Soak an hour or so and wash off. Brush with a soft/fine brass brush (toothbrush will work if you don't have a brass brush) and soak some more. Repeat as many times as needed to get the desired look. It will take on a shiny black patina that will buff to a nice shine with a soft cloth. It holds up very well, too.
This same procedure works even better with silver fittings. In silver, it creates surface similar to niello, which is both black and hard.
 
Well Mr. Apelt, you must be telepathic.
I ordered liver of sulphur two days ago.
After the shop session yesterday I told my wife "I think I'll make a wooden model of the nakago to use for shaping and checking fit." Some of the hardwood scraps I have will stand up to the gentle hammering and be easier to shape. Plus I don't have any metal that's as thick as the shinogi, so let me give this a try. Being the first try at a habaki, if I have to toss this one and start over, I really won't feel too bad about it. But it would be nice to do the "See what I did on the first try." thing...
 
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Go to Home Depot/Lowes/hardware store and get a bar of the welding steel they sell. It won't harden very much, but will work fine for a mandrel. You really don't have to harden it at all if you don't want to.
 
A chunk of scrap purpleheart worked fine.
Now I need to do some internal filing and some on the nakago. Apparently, I still don't have a good taper there. But I'm getting close...
 
Just an update. My priorities were redirected this week. (Wife seemed to think the leaking humidifier supply line valve should take precedence. Go figure.)
I thought I was close with my machigane fit up, but realized it was lacking. Made a new one that seems to be a little too tall. Unfortunately, I've already soldered it in place. After spending some time filing, I think I'll see if I can remove it and correct the placement. Failing that, I'll just start over using what I've learned so far. One thing I've learned is that the $450-$600 charged by a professional is a well earned wage.
 
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