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DaveJ

WIP: Shobu Zukuri Kotanto Mount - parts of Model T fender from the forest!

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Its been awhile so its time to pull back the curtain again...i am adding these photos to the "process" section of my website as well...

The blade in question is the last of my "new old stock" from a couple of years back, forged at an outdoor demo, originally as a scaled down piece but I decided to mount it as a regular kotanto. Unusual geometry for tanto, shobu-zukuri is generally reserved for larger blades but it seemed to be where the steel wanted to go.

This thread will document the mounting, working from the habaki, then back through fuchi/kashira/tsuba/seppa/tsuka/gangimaki, etc...I will try to add a couple more technical notes here.

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A scrap of copper bus bar hot and cold forged into a butterfly, this will be the outside, note the step down from the mune and that the front is much narrower than the back all the way along each "wing".

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This will be the inside, note the mune has a concave distally to prevent high centering when bent, and a smaller radius concave laterally.

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As much shaping as can be done before bending is good, but too much is trouble! The "wings" are far too long, but the scrap was already cut off from another project.

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Annealed and bent in several stages, then trimmed closer to final size. The machigane is cut and forged from one of the scraps.

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Machigane more or less in place, fluxed with borax and a strip of hard silver solder set on top of it. The rusty/oxidized steel wire provides pressure when heating but is less likely to stick to any escaping solder. The habaki is formed and soldered slightly undersized (just a little ways back on the tang) so it can be hammered to the finished dimensions later.

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Heating in the charcoal forge, surrounding it with charcoal away from the air blast provides a nice carbon-rich reducing atmosphere.

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As soon as the solder flows well, it is removed to cool slowly, this avoids unnecessary stress on the joint.

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Hammering stretches out the habaki to its final size while hardening the copper. The goal is to arrive at both at the same time.

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Files and water stones refine the exterior geometry polished the surface, then it is frosted with a stream of poured stone chips about the size of large cat litter...half masked with my thumb to create a transition zone. My thumbnail has a similar frosted pattern...the habaki will be given a final polish and patina after all the saya work is finished.

Edited by DaveJ

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Kashira (pommel)

 

This kashira was made from steel harvested from a Model T fender bracket. Because of the type of wrapping that will be used for the handle, it is held in place by a combination of kusune (pine resin glue) and steel clips rather than by ito wrapped through shitodome ana.

 

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Raw material: the bracket from a Model T (as far as i can tell) rear fender that I found in the forest last year.

 

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Cut off with a cold chisel.

 

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Hot chiseled to a rough oval shape and hot punched through a ring to start the rounding process. I reshaped an old claw hammer face into a punch for this work, it still needs rounding off some more so the corners don't stress the work as much but I have not yet committed to a shape for it.

 

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Hot punched through a slightly smaller opening, this time an old sledge hammer eye with a nice shape to it.

 

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The domed shape at this point. It will go one more time through a slightly smaller hammer eye using a hardwood punch.

 

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Filing off most of the excess save for the two tabs.

 

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The tabs are forged and filed to shape and the surface filed, smoothed, and then hammer textured before heat bluing in the forge.

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Dave,

 

Looked at your website and this post ..I am at awe , wonderful stuff...thank you.

 

Jan

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Fantastic work!!! thanks to share... very beautiful photo as well

I love your site web too, and your work! (of course ;) )

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Fuchi (ferrule)

This fuchi is made mainly from steel harvested from the Model T fender bracket. Its construction is similar to the Higo style in that the copper tenjo gane is forged in physically rather than soldered to the sleeve. The band was created by forging an existing screw hole in the bracket to stretch it to the size of the handle-to-be.

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Raw material: Another bracket from the Model T fender from the forest.

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The last screw hole is cut off with a cold chisel, this little bit will become the sleeve around the handle, can you see it in there already?

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Second round of forging, using a tapered punch to spread and then forge against to create a torus shape.

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Third round of forging, it is beginning to expand and has the correct cylinder shape, just needs to be stretched out evenly from here.

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Fifth round and getting close, now it is large enough to be forged on the tip of the anvil horn. Note the kashira for size reference. You can see that I used the cross peen to widen the band more than lengthen it at this stage as it is pretty close to size.

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Seventh round or so, this is the final size and shape, it will be filed inside and out to even things up a bit more. The inside taper is a key component of this style of fuchi construction.

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A reclaimed copper bus bar is annealed in the forge. The lovely colours are naturally occurring oxides from the heating and water cooling.

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Cold chiseling the copper before rough filing the profile.

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The nakago-ana is cold chiseled and then the edge is tapered to match the taper inside the sleeve and carefully filed down until it sits just below the lip.

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The lip is peened down over the rim of the tenjo gane, locking it in place against the tapered inside of the sleeve.

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The rim is filed level and the nakago ana opened up to its final size and shape. The tenjo gane of the fuchi should not touch the nakago so it does not need to be close fit and adjusted at the time of assembly. (only the habaki, seppa, seki-gane or tsuba, tsuka core, and mekugi ever touch the tang)

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The outside of the sleeve is given its final shape by filing. Subtle curves and radii everywhere is the way nature flows.

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Before and after...well...during, actually. That countersunk hole is the starting size for the fuchi sleeve.

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Peened with a small hammer to planish the surface and give some texture.

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After heating in the reducing area of the charcoal forge until just at blue/black...a recycled car!

Edited by DaveJ

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@Jan, @Franck...thank you! much appreciated...

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Tsuba (handguard)

 

Tsuba for tanto are usually either non-existant or are very small. This leaves little room for embellishment so the focus is often on the rim, or the material itself. This tsuba is made from wrought iron, an old form of bloomery iron produced up until about a hundred years ago, and will feature only the character of the iron itself. This is a small scrap off the end of a timber bridge spike that came from the forest. You can often spot wrought iron in the wild as it will rust into a wood grain like pattern, whereas modern steel rusts into a moon-crater like pitted surface instead.

 

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This is the bit before starting, it was a gift from another blacksmith who cut it off as part of a test to see how well the old iron would forge weld where it had cracked. About 7/8" long and 5/8" square. I don't think he expected me to turn that little bit of scrap into a centrepiece for a project...

 

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A couple of rounds of forging spreads it to about a fourth the thickness and four times the area. Wrought iron needs to be forged much hotter than mild steel or it will crack along the slag layers.

 

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These lovely layers that are revealed by the fire are the edge look I am after for the finished tsuba. They are called tekkotsu (steel ribs).

 

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The nakago ana is partially drilled with a post drill to prevent the iron splitting along slag layers, then cold chiseled and filed to shape. A bevel is removed by cold chiseling to allow the top and bottom seki-gane to lock on.

 

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The outside is cold chiseled and filed roughly to shape.

 

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Once the final shape is filed, drawfiled, and planished, the tsuba soaks in a fire with a strong air blast to reveal its inner workings again. The high heat and oxidization reveal the tekkotsu and a combination of wire brushing and dipping quickly into water removes the scale while it is being heated. This heating process is known as yakite or yakinamashi.

 

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After yakite, any remaining scale, seen here as dark stripes, is removed by soaking in a weak solution of vinegar and hot water.

 

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The omote side showing those lovely layers that have been in there all along.

 

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The ura side after hammering the copper seki-gane into place and suspending in a jar with warm vinegar vapour for about an hour, round two.

 

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After spending the night hanging in the jar above the vinegar.

 

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After burnishing with an antler tip, the traditional way to restore flaking rusted iron without removing the patina.

 

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After boiling in tea to darken the surface, the tannins react with the red iron oxide and convert them to more stable black iron oxide, this is a traditional finishing method for cast iron kettles (tetsubin)....the reaction brings quite a striking change.

 

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After a thin layer of fukiurushi, urushi lacquer applied and wiped off, it reacts with any remaining red oxide and turns it to black iron oxide. Once cured, a final layer will give some gloss and bring back some of the warm tones.

Edited by DaveJ

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Seppa (spacers)

 

There will be two brass seppa on this mount, one on each side of the tsuba. The final fit to the tang is achieved by using a punch to push out four lobes of metal in the four corners and then filing to adjust slightly. The seppa are cold chiseled and then filed from a sheet of brass reclaimed from a door push plate.

 

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Cut with shears, nakago-ana chiseled out, filed to shape. Note the shape of the nakago ana before fitting.

 

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The seppa after fitting. They will be given a final polish (around their rims and the front of the one next to the habaki) at the time of assembly.

Edited by DaveJ

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Great stuff Dave.

Fine photos too.

 

Jim

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Wonderful! I never would have thought to drive the kashira through a hammer eye to get the domed oval, or to work the fuchi out of an existing hole the way you did. You are a master of the unconventional, and I'm pinning this thread. B)

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Hey neighbour , enjoying this wip thus far , great photos , looking forward to more.....

 

Rob

Kelowna BC

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thank you, gentlemen! much appreciated!

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Tsuka (handle core)

 

Once everything between the habaki and the handle is at finished thickness, the wood core can be made. Tsuka are split and carved to fit precisely around the nakago and then glued back together with sokui (rice paste glue). Then the outside is carved, taking into account the size of the fittings and the thickness of the wrappings. This one is made from a scrap of Yellow Cedar.

 

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Bound with leather and wedged overnight to dry. The leather gives a nice even pressure even when the starting block is not square and true.

 

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Fit on the tang, the fuchi is used as a starting point to set the dimensions of the block and it is squared down to size. Our local Yellow Cedar is wonderful stuff to plane, carve, and smell...golden, glossy, and spicy/earthy scented.

 

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Using the fuchi as a guide, mouth is carved down until it just begins to fit into place.

 

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The kashira sets the measurement for the other end of the handle and wood is removed between the two and adjusted until things align nicely.

 

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After some calculation adding the thickness of the fuchi and kashira and subtracting the thickness of the rawhide and leather wrap, the excess is removed. This is the ura so a double layer of shikagawa (rawhide) will rest here in a style of maedare gise that countersinks both ends of the wrap.

 

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The omote, showing the tsuka-shitaji carved oversize to accommodate the layers of wrapping that will go over it. Tsuka-shitaji were originally designed to make room for the end knots to sit lower for standard wrapped handle styles, however they are often included on the omote side of unwrapped handles as well. My theory is that they serve as a reference point for registering the position of the handle and direction of the blade by feel...on tanto length handles, the pinkie finger sits right in the groove on the draw.

Edited by DaveJ

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Massively impressive. This has to be one of the best wips I have ever seen. Please hurry and finish Dave.

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Wow, that's just awesome. Really looking forward to seeing this finished.

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I learned something at every single step, thank you for sharing.

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Tsukamaki (handle wrapping)

 

There are generally two components to wrapping a handle, the first being the shikagawa (rawhide) or samegawa (ray skin) layer which adds incredible stiffness and resilience to the tsuka, and the second an optional leather or cord wrapping to add padding, grip, and compression to the tsuka. When possible, the shikagawa or samegawa will fit part way under the fuchi for extra strength and integrity, but in this case stops at the boundary of the leather wrap to allow the rolled leather to sit in the groove. The style of wrapping is called gangi maki, a spiral of leather with a rolled front edge wraps from fuchi to kashira beginning and ending on the ura side.

 

shobu-zukuri-kotanto-69.jpg

The double channel style maedare gise allows the shikagawa to sit flush with itself on both ends of the crossover. Here the rawhide has been soaked and bound until dried in the exact shape of the tsuka. More info on wrapping via the Kashima sisters: http://www.ksky.ne.jp/~sumie99/samewrapping.html

 

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When dry, it is removed, glued on with sokui, and bound again to dry in place overnight. Any bulges or inconsistencies in the surface are pared off with a chisel and then, because shikagawa is much smoother than samegawa, it is scored all over with small cuts to give a better tooth for the glue to bind to.

 

shobu-zukuri-kotanto-71.jpg

A paper pattern determines the exact shape of the wrap, this leather is scrap from a reclaimed vest. The leading edge of the leather is angled to match the wrapping pitch for the first turn, starting on the ura, and when it gets back to itself it straightens out...it takes a bit of play and adjusting the paper to get the pitch and width correct for a particular handle, and in this case I also had a limited length of leather to conform to. The location of the mekugi ana on both sides in relation to the wrap is important to consider in the paper template stage as well.

 

shobu-zukuri-kotanto-72.jpg

The leather is pasted with sokui (rice glue) and rolled as it is wrapped tightly around the rawhide. The ura side showing the initial crossover and the final travelling off under the kashira clip. The goal is to get the roll to overlap right next to the edge of the previous turn, so that it holds it down but does not create another ridge out in the middle somewhere.

 

shobu-zukuri-kotanto-73.jpg

The omote showing the rim where the kashira clip will grip. The mekugi ana was drilled with a kiri and adjusted with tapered round files before applying the leather wrapping. The kanji for gangi means a shape like steps, or the terraced shoreline near a seaport.

 

Kensen~san's excellent diagram for gangi-maki: http://www.thejapanesesword.com/forum/viewtopic.php?f=29&t=124

 

and some nice old examples:

http://www3.ocn.ne.jp/~saka7733/17.htm

http://www.samuraishokai.jp/sword/10129.html (this one is a tachi so everything is reversed, remember...)

Edited by DaveJ

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What everyone else said, thank you for sharing your process. I have just started my first Katana, and I think I will need to do a lot of research and study for when it comes time to make all the fittings. Great work, and please keep it coming.

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Great, Dave!

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@Matt, one of the best things you can do to prep yourself is to immerse your eyes in examples of antique swords...the subtle details and proportions can make or break the Japanese aesthetic and the old stuff provides a stable foundation of a thousand years of research and design to build upon...i've got lots to learn yet too...

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Thank you for sharing this with us! and great photo's too

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Great stuff again. I am really enjoying your aesthetic and the reclamation of materials. I had seen that wrap style on katanas but never on a tanto. Interesting...

 

I look forward to visiting with you this summer.

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@stuart thanks! i haven't been able to find an example yet either, but i am on the lookout...i have always liked the style because it is so utilitarian but can be done so elegantly too...

sounds good!

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Wonderful!!!

 

Thanks for sharing.

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