WIP - Sunahama Kotanto, kaiken meets aikuchi...finished!

[islandblacksmith]

a new client piece, first official commission of the new year, the goal to create the original samurai "EDC" knife, the kaiken mounted tanto...this one will be a good design challenge due to the micro size of the blade and the constraint of creating a mount small enough to fit in a modern pocket while still honouring traditional proportions as much as possible...at the moment the plan is to house the blade in a wooden mount more like shirasaya than the usual rounded and lacquered kaiken style...but this will likely evolve as things progress, first step is to get a live blade through the fire.

(edit) skip ahead to see what the final goal is: http://islandblacksmith.ca/2014/04/sunahama-kotanto/ (/edit)

i will start from today as i cooked batch of charcoal yesterday and it seems a fitting place to start...then back up and get caught up to real time...the forge is fueled with softwood charcoal made from deadfall, construction or mill scrap, pine if it can be found but this time of year i'll take most anything dry...this batch was graciously provided from the scrap bin of a local construction crew specializing in exteriors so it is mixed pine, red cedar, balsam fir, and a little fir, i had more overcooked pieces than usual, i think the larger chunks of wood dragged the process out too long...more about the charcoal making here: http://islandblacksmith.ca/how-charcoal-is-made/

cold and sunny (read: not raining), about as good a day as any for cooking charcoal this time of year

large wood chunks and heat sink of the solid frozen ground ran the batch long into the moonlight, just a nice shot of the combustion chamber to pass the time

this is a piece of nicely cooked charcoal, it looks like a piece of wood still, not dusty, crumbly, or soft, rings when tapped, and has enough remaining volatiles to give a nice yellow or blue flame in the forge

three full galvanized trash cans of chopping and screening later, the bin in the shop is full, it's hammertime...also: hundred year old diy shovel still going strong

 

[islandblacksmith]

the raw material for this blade is a thick 24" circular millsaw blade, i have used this material on a couple of pieces and it responds very well to forging and yaki-ire and happened to have a piece just about the right size for this project...forged with charcoal, by hand...not as much water as i could have but it stayed pretty clean...

the blade in the foreground is the raw material, half of this belongs to a friend, half is mine in trade for some tempering work...i quite like working with this piece of steel!

the forge is two rows of firebrick with the air coming in on the left side near the bottom, simple to set up and adjust...i usually have a half wall inside to conserve fuel for smaller work

sunobe enough for this piece...the closest edge will be the cutting edge, the tip will be turned up as the bevels are forged in...normally i would use the whole piece and let the volume determine the final length but since this is being made to a strict length, the excess will be cut off the tang as it shapes up

forging is finished, the thickest part is at the mune machi (just right of photo center), the steel tapers away in three directions... (the slight angle makes it look a bit wavy but its fairly straight)

felt so confident with the overall shape i decided to stamp it right away, often i wait until rough shaping to make sure the placement is alright

finished shape out of the forge, i file the machi in on such small blades...still have to work on the slight bulge in the spine i often forge in right behind the tip

cooling in fine wood ash, the container is a bit small/underfilled so i focused on the nakago where the most filing will need to be done next

after a little filing around the profile and setting some approximate machi, an angle that shows how clean the water forging can leave the surface...dark marks near the tip are charcoal lines from annealing

forgot to take the sketch with me but did alright it looks like...the machi will have to move forward but that's much easier than backward!
the sketch was very rough, just to find proportions and determine if the blade would fit in the overall length we are aiming for...the tip will pull up a little during yaki-ire but i doubt too much with this little blade...

 

[Lorien]

sweet thread.

 

[ScottRoush]

cool stuff. Are you using direct burn for your charcoal?

So you distinguish 'shirasaya' from 'kaiken' mount then? I thought the term shirasaya was simply a saya/tsuka that flow into each other in a seamless way?

 

[evanPGH]

Subscribed =)

 

[Kohai999]

So you distinguish 'shirasaya' from 'kaiken' mount then? I thought the term shirasaya was simply a saya/tsuka that flow into each other in a seamless way?

Shira saya means "white scabbard". It is intended as a "rest" scabbard for the sword blade when it is not in formal mounts.

Best Regards,

STeven Garsson

 

[SBranson]

Great thread. I kinda got lost in the charcoal making links and such. Fascinating. I really like the pace and attention of your work. I'm looking forward to visiting.

Scott: exactly what STeven said. The wood used and the finish are to provide an atmosphere conducive to storing a blade so it won't rust. The lacquered scabbard of the mounted sword protects the wood and blade from moisture if you are wearing it but would trap moisture inside as well.
The Kapps' books show the construction well and some of those photos show how perfectly the inside of these are shaped.. I love that fact that though you'll never see it and in some ways it's not crucial that every thing be perfect, it still is...
This is the spirit of this thread and Davej's approach. I like this...

 

[ScottRoush]

Okay thanks guys. I was confused from something I had read. I kind of knew about the shirasaya in regards to it's use as temporary mount (although the moisure issue was interesting)... but that the overall term was related to the transition from tsuka to saya and the resulting shape. Makes sense now.

I was wondering if you two have or would meet!

 

[flatblackcapo]

Subscribed!

 

[islandblacksmith]

thanks, @STeven!

@ScottRoush
aikuchi = regular koshirae, no tsuba (carried as a regular nihonto)
shirasaya = resting scabbard of wood only (for storage or blades without koshirae)
kaiken = no tsuba, may be smaller, often rounded, lacquered, and unadorned (to slip into clothing easily, not necessarily for public display as those worn on the belt are)
(i typed the above before Stuart checked in and elaborated, but will leave it for posterity)

not exactly but technically direct burn i guess...the wood in the photo above is not part of the charcoal batch but is supplying the heat for it...it is not a retort though, the flue gasses from the combustion chamber flow through the pyrolysis chamber directly...it is a kiln based on a japanese design...more info on the kiln here:

http://islandblacksmith.ca/2013/03/charcoal-kiln-v-3-0/

..and thanks much @Stuart!

 

[Lycosa]

Read post #3.
Aikuchi next.
rolf

 

[ScottRoush]

Okay it's clear as a bell now.. Thanks Dave.

Hmm.... yeah that method isn't technically direct burn and isn't retort either. It's actually similar to a method I have for making small batches of charcoal. I use metal paint buckets with crimped on lids and a hole in top. I pack the bucket full of scrap pine lumber, crimp the lid on and throw it in a fire. When the flames stop shooting out of the hole I turn the bucket upside down to seal the hole on top. Makes beautiful charcoal with no loss to ash. Same basic idea as what you have illustrated.

 

[islandblacksmith]

this is a short one, photographically speaking...hand filing to set the machi, shape the nakago, and clean up the blade lines, particularly the tip...nothing technical, just clamped in my old leg vise and filed...i take it out often to hold it against the light coming in the door, checking the silhouette, and sighting down the lines...in this stage i am not touching the flats, only working the outline shape.

the blade outline is finished, i will likely use a komaru spine on this as the blade is already small and will have a yoroidoshi feel to it with this much thickness...setting the mune machi notch a little south of where i want it, removing most of the material in the triangle between the machi and the forged tip corners of the nakago

going back in a refining the lines, squaring up the notches to each other and finishing by drawfiling around the outline...i like to leave the tip of the nakago as forged, kind of like a "truth window"

next step will be to tackle these sides...

 

[ScottRoush]

thanks, @STeven!

@ScottRoush
aikuchi = regular koshirae, no tsuba (carried as a regular nihonto)
shirasaya = resting scabbard of wood only (for storage or blades without koshirae)
kaiken = no tsuba, may be smaller, often rounded, lacquered, and unadorned (to slip into clothing easily, not necessarily for public display as those worn on the belt are)
(i typed the above before Stuart checked in and elaborated, but will leave it for posterity)

Hey guys... Just got my Kapps (the Craft of the Japanese Sword) in the mail today. According to them the shira-saya was a crudely made scabbard intended for swords donated to shrines. And then during the later Edo period you had the yasume-saya or 'resting or storage saya'. Not sure if this book is the final word on these terms.. but they make an interesting distinction.

Also.... they bring up something that has been bothering me a bit. When you are making such a tight fit.. what happens when you get wood swelling/shrinking due to climate differences. This seems like a much bigger deal these days when you can make something in absolute dryness of a Wisconsin winter and then ship to Miami, Florida. The saya maker in the book compensates for a much looser fit before shipping to a humid climate. Any thoughts on this?

 

[islandblacksmith]

i have The Art Of The Japanese Sword (http://www.theartofthejapanesesword.com/) instead so i can't look it up...

off the top of my head: maybe they are speaking of the history and progression, in that originally no one had shirasaya, it was only for shrine swords that would never be used, every active blade just had its koshirae...once the edo kicked in and swords weren't in use (and the market needed some expansion!) it became a normal thing, and continued into the era of collecting where you need not ever have a koshirae, in effect all swords become shrine swords in a sense of the word!

yasume means resting literally...as in, "are you working today or yasume?" so that would be the literal "resting scabbard" but shirasaya is the most commonly used term these days...we could bring yasume back, though, i'm in favour...

this just in: the internet says there is a third fairly equivalent term to the above two called aburasaya...abura is oil, maybe because long term storage tends to cause oil to build up in the saya, and its much better to have to split a plain wood one to clean it out that the lacquered nurisaya...

***even more info, my "learn something new" moment of the day: kashima sisters at it again...here is an old form of resting scabbard for when you aren't going to unmount the sword, but want to store it between uses...a saya for the sword and a plug for the nurisaya: http://www.ksky.ne.jp/~sumie99/koshirae12.html i'm calling it "shirasaya for warriors"

 

[ScottRoush]

Yes they brought up the abura-saya too..I didn't mention that as they seemed to think the term interchangeable with the yasume-saya. Just to be clear.. I wasn't trying to counter how you guys were defining the terms. I assumed that the shirasaya just became the conventional term over time. It sounds nicer anyway.

 

[islandblacksmith]

@Scott, the fact that you are ahead of the curve on learning these old terms means you are one of "us guys" too, no use denyin' (￣(&#12456&#65507

here's a couple clips of the good, bad, and overcooked from the last batch of charcoal
along with a shot of each type of charcoal in action:

[video=vimeo;86486489]https://vimeo.com/86486489[/video]

 

[islandblacksmith]

once the profile is established, the next step is to set the final edges of the spine and pre-quench edge and then remove the material between using sen scraper, filing, and draw filing...the staple vise is called a sen dai and holds the work between blocks and wedges of wood under a sturdy iron staple...takes a bit of getting used to but is quite quick to set up and change...

taking down the spine edge of the nakago with a sen scraper

focusing on the edge side, a surprising amount and size of material can be removed by scraping (the nakago is not as peaked as it looks, just the tool marks and light)

the material in the center is scraped last and and then smoothed out by drawfiling (the nakago is not as rounded as it looks either)

working on the blade, ura side

a shot of the sen dai and various wedges to create proper angles and support for this thick and small piece

scraped

draw filing to flatten and true it up

omote side, showing how the edges are set on a low angle first with the sen, and then the center material removed down to them

finished by draw filing

another couple shots of the wedging system for this blade

the angles are tailored for the shape of the tang or blade

cleaned up with a slab of local sandstone to check the surfaces and get the feel of the geometry on a stone

next step will be to prepare for yaki-ire...

 

[evanPGH]

This is just fantastic, Dave.

Thank you so much for the explanation of the process and especially for the pictures, they're gorgeous. I feel like I'm tucked in your little corner of Vancouver island, right there with you.

The way you choose to do things continues to amaze me. Can't wait to see what's next!

 

[Lycosa]

WTG, Evan and Dave!
rolf