For some reason related to our love of Japan, I've built a custom iaito from scratch.

Each thumbnail shows the progress of the various parts.

Lengthening the nakago (!)
The tsuba
The habaki
The kojiri
The koiguchi
The fuchi
The kashira
The tsuka

This describes some of the stages by which I made an iaito. An iaito is an unsharpened katana-like sword that is used for iaido, and for various reasons, not the least of which are safety and cost, such swords have their blades made of a zinc-aluminium alloy.

Safety? Well, when struck against a tough object, the blade will bend and then break. The metal is sufficiently soft that it is not possible to give it a sharp edge that will survive contact with any substantial object. Yes, you probably can cut yourself badly with one, but a gashed thumb might be the result rather than no thumb at all, as could happen with a shinken.

Nakago

I started out with a bare blade, no fittings, and a serviceable saya. The first thing I did was to assess the length of the nagako (tang) as I would happily trade authenticity for safety. You see, the cost of iron in feudal Japan, and the need for a blade that would survive relatively few impacts in its life, probably contributed to the adoption of nakago that did not run the whole length of the tsuka (handle). If the style of fighting consists of executing at most half-a-dozen full-strength strokes in the life of a sword, then there would have been no need to use a more robust design.

Thus, when contemplating an iaito, and trying to maximize its life (and safety), it makes sense to give it a nakago that runs the whole length of the tsuka. Plus, I like a challenge and have seen a few forum threads that suggest that this is impossible.

:)

I intended to lengthen the nakago by around 40 mm. You can see how my hands would be positioned on the original tsuka - and I just didn't like the idea of a partially supported nakago end. I cut and filed a suitable extension piece from non-tempered aluminium plate (6mm thick), and then bought a Technoweld repair kit. This consists of 5 rods of a proprietory alloy, a stainless steel scraper, and a stainless steel brush. It is a marvel. It allows you to make tough and non-peelable fusion welds with aluminium, zinc, and zinc-aluminium alloys such as zamak. I've not been this impressed since the time that I found that I could soft-solder aluminium with bike-oil as a flux/oxide barrier. Anyway, if you follow this route, be careful not to put the Technoweld in the flame (propane/butane with a Bernzomatic torch head) for long, it oxidises fairly quickly. A few pits didn't fill too well, so I drilled them back to fresh alloy/aluminium, and reflowed them.

Kashira

I bought a chunk of buffalo horn from eBay. It was quite easy to cut with a hacksaw (but the smell of burning hair may turn your stomach), could be filed readily, and took a lovely polish. Small files, sharp knives, and a good supply of jewellers rouge were used.

Fuchi

Sheet copper, cut into a strip and an ellipse, the strip brazed with silver solder, the ellipse brazed on top. Then, a small piece of stainless steel filed into a maple lead, and brazed to the copper. I used Ceramit, a bake-to-cure enamel, that comes in black and clear, and I then brushed and buffed till I was happy.

Tsuba

For various reasons I thought that a suitable theme for the iaito would be the maple leaf. So, a little work in Illustrator produced an EPS file, and I deliberately left the centre hole out as I suspected that the best fit would be obtained by another file-fit-file process just like the habaki. I didn't trust myself to measure the nakago accurately enough for it to be cut. I contacted SCISS ltd, of Kent, England for the cutting process; they specialise in waterjet cutting which for this thickness of mild steel (5mm) is an excellent choice. Unlike laser cutting, there's no warping from work-heating, and it's a little cheaper too. I was rather conservative with the EPS file, relying on my Honaeur files to take off the last mm or so of the design.

Blackening was achieved with judicious use of a gas burner and water - nothing fancy, no acids, no peroxide, just the normal kinetics of the oxidation of mild steel in air with regular water sprays.

Despite great care and attention, there will be gaps between the tsuba and the blade. These gaps are filled on the ha and mune side of the blade with the use of sekigane. The purpose of this filler plugs is to act as a buffer between the tsuba and the blade and so remove the chance for the blade to be knicked by the iron of the tsuba. On shinken, the sekigane is often copper - but for an iaito, where the blade is relatively soft, it makes no sense to use such a tough metal. I used pewter for the sekigane, lead would do, but I've ingested enough of it over the decades and am trying to be RoHS compliant.

After filing some recesses in the tsuba's ha and mune sides, I cut out some plugs of pewter, filed them to a coarse fit, and tamped them home into the tsuba. The blade was offered up multiple times, with the excess being filed away.

Menuki

I prefer a simple style for tsuka furniture. I took a 6mm diameter stainless steel pipe, cut it a ~30mm length, and then cut it along its length into two half-cylinders. A gentle groove was filed into their mid-section, they were gently bent and filed so that they took on a gentle 'hump-like' appearance when viewed from the side.

Saya

I made some rather unusual alterations to the area where the koiguchi fitted. Basically, I didn't trust the saya wood entirely to withstand the tensile forces exerted by the habaki when being sheathed. So I took a thin strap of stainless steel, brazed it into a hoop, carved a channel into the saya, reduced the saya diameter above that channel, and slipped over the stainless steel hoop. I now kick myself vigorously for not taking any photographs during all this. But if you were to run the saya through an x-ray machine (!) you'd see a roughly 5mm wide band of metal just under a layer of bondo and paint.

Aside from the koiguchi reinforcement, I didn't do much to this - a few fresh coats of a black gloss paint, half a litre of elbow grease and polishing compound.

Tsuka

There's an excellent timber merchant close to Southampton, Totton Timber Co., who sold me a piece of liriodendron tulipifera which is the closest that I'm likely to get to honoki. It was sawn in half, reversed to give the strongest grain, and then asymmetrically carved so that the nakago lay away from the seam, I had a tsuka. The meguki is made from African Blackwood, which has a Janka value a smidge higher than that of dense bamboo. I chose this wood because firstly, it was in my box of odds and ends, and secondly, it's almost as dark as ebony and so hides well in the black samegawa of the tsuka. Yes, black rayskin.

The ito is silk, and in the time between photographing the core and almost finishing the ito wrap I have moved country twice, and moved house three times. Images of the wrapping process simply fell by the wayside. There's a quick shot here of an intermediate stage, note the hashigami - I experimented with both card stock and folded paper - couldn't really see a difference in their use. For the actual tying process, as of mid-2012 there are two excellent YouTube videos by Hyoujinsama that are worth watching. These are linked here and here. The tying guide by Thomas Buck is also good to have on hand.

Seppa

Cut from copper sheet, these seppa are not unusual in any way. I had to smooth one off and flatten it a tad to enlarge it again after making a mistake. I decided to have a non-bright finish for the seppa and so they were zealously cleaned and then gently baked on an electric oven ring for a few minutes. Rinse and repeat. If it's done slowly enough the copper oxide finish is both uniform and durable.

Kojiri

A set of files and a hand saw turned a chunk of deer horn into a rather pretty kojiri. I used Commandant (a dutch form of T-cut, it has a water-based solvent rather than a petroleum distillate) to polish it up. I admit to cheating, by using a power drill with a milling bit to ensure a square-based elliptic-cross-section cavity in the kojiri, so that the saya would snugly fit into it.

Then, a 2mm drill bit and a bit of care yields the hole for the ito to pass through. A little filing, a lot of polishing, and it's done.

Habaki

Now, a traditional method of making the habaki is to take a strip of the metal to be used, beat it into a 'C' shape around the blade nakago, then file and hammer till a fiducial solder joint is all that's needed to make a complete collar. There's a lovely description of this method here SCNF.

I've used a different approach. Rather than have a joint in the habaki, I decided to carve it from solid. Thus, I took a block of copper, and drilled and filed till I had a little mountain of copper dust and a finished habaki. In this way the machigane is avoided, as I carved the step into the habaki that accepts the corresponding notch in the blade's ha.

When making the final fit I used a broad-tip marker pen to liberally paint the nakago and then offered up the habaki. I'd take it off and note where the ink was transferred to the inside of the habaki, before filing down the high-spot with jewellers' files. The machigane was, predictably, the hardest part to shape and took hours of carving with a reshaped 'stanley' knife blade. Again, marker pen on the blade, offer up the habaki, note the high spots and file 'em down.

Once the habaki was shaped appropriately, I decided to give it a brushed satin finish - achieved with 800+ grit emery. The finish was protected by thin coats of Ceramit clear solution, a bake-to-cure two-part mix that is almost as tough as fused enamel.


So here's the finished item. And for anyone else with a half-finished project, don't give up. From start to finish this took 6 years, off and on (more off than on) and survived moving country twice.