Process: Making the Tsukimi Tanto
The blade is forged from a reclaimed Caterpillar tractor engine part. Materials for the koshirae include copper bus bar and water pipe for the fuchi, kashira, habaki, and kurikata, silver and nickel-silver spoons for the hammer-textured seppa, and a steel spike salvaged from thirty feet under the Pacific for the heat-blued tsuba.
Fuchi & Kashira
A rusty reclaimed Caterpillar tractor engine part will serve as the raw material for the blade.
The end is forged thin and quenched in water from a red heat. If it snaps when placed across a gap and struck with a hammer, the carbon content is high enough to make a blade. The fine grain structure revealed in the break indicates a high quality of steel.
Handmade softwood charcoal fueling the forge as the sunobe is formed and shaped with a hand hammer.
The sunobe determines the overall volume of the steel and intended geometry. Shown in comparison to the original piece of steel, the ends cut off and the break test visible on the right.
The second phase of forging expands the sunobe into the final geometry.
The blade after final forging. The most notable areas needing work are the machi and the bulge along the edge, which will be removed using hand files.
The blade profile cleaned up with files. Again shown with the original part for size comparison. Elements of its form are based on the Aizu Shintogo Tanto.
The blade in a sen dai vise, bevels being rough shaped with a sen scraper, files, and smoothing by drawfiling.
Once the tang is close to final dimensions, the kamon is hot stamped on the omote side.
The blade before hardening, after final smoothing by drawfiling.
Clay layers dried and ready for yaki-ire, differential hardening in water.
The habaki is hot and cold forged from a piece of copper bus bar.
A machigane is made to bridge the gap at the edge and then soldered in place in the charcoal forge.
The habaki is hammered to harden and stretch it to its final size, then the shape is refined with files.
It is cleaned up and given a filed texture, then allowed to patina.
A steel spike salvaged from 30 feet under the Pacific Ocean.
Forged flat into the tsuba blank. The nakago-ana opening is first cut with a cold chisel and then enlarged with files.
Heavy copper wire is upset and forged into sekigane to keep the steel from contacting the blade. The sekigane lock into chamfered edges in the tsuba.
The sekigane are filed out to a precise fit with the blade.
Later in the process the tsuba is shaped to match the profile of the fuchi.
The edges are polished and the face finished with yasurime (filemarks) before using heat from the charcoal forge to blue the steel.
The deep blue-black colour after heating to a controlled temperature.
Silver and nickel-silver spoons serve as the raw material for the seppa.
The spoons are cold forged flat and cold chiseled to open a nakago-ana, then escapement files are used to clean up and enlarge the opening.
A shot of a test fitting on the tang before cold chiseling the outside to rough shape.
A texture hammer is used to create a surface pattern without removing any of the silver.
Later in the process the seppa are filed to follow the profile of the tsuba and precision fit to the tang using punches and escapement files.
Fuchi & Kashira
A piece of reclaimed copper bus bar is cold chiseled open to form a nakago-ana for the fuchi.
Escapement files are used to form and clean up the approximate opening and the corners are cut off with a cold chisel.
The outside is shaped and given a slight angle to fit tightly into the forged ring, which also has a slight taper.
The edge of the ring is forged slightly around the edge to lock both pieces tightly together and the excess is removed with a file. The natural colours of the fired-copper patina will be left on the finished piece.
The kashira is begun by forging a piece of the bus bar with the same texture hammer used on the fuchi.
The plate is rounded and punched into staged forms until it reaches the final profile. The excess material is removed with a file.
The split Nootka Cypress is carved to fit the tang, beginning with the omote half.
Showing how the fit is calculated and tested using the fittings and estimating for the thickness of the fuchi.
The halves are glued together with glue made from rice paste and then carved to shape.
The tsuka core is carved to fit the fuchi and kashira snugly.
Later in the process it will be fitted and wrapped with samegawa and then sanded, lacquered, and polished.
A scrap piece of Nootka Cypress is selected for its tight, straight grain and then split in half to align the grain with the finished saya.
The insides of the two halves are hand planed until they fit flush togther again.
The omote side is carved out first, allowing for the edge to sit fully inside this half.
The ura half of the block is carved out next, testing continually for a snug and accurately aligned fit.
Sokui, paste glue is made from rice and water, is used to reattach the two halves back together.
The block is wrapped with a leather cord and wedged to provide pressure where necessary, then allowed to dry overnight.
A paring chisel is used to carve the koiguchi to the final profile outline and a plane is used to square up the block and remove excess material from the four sides, almost to the line.
A plane is used to trim the four sides further and to remove the four corners of the block down towards the final profile.
The corners are continually removed by planing until the saya is rounded and smooth.
The tip of the saya is rounded and smoothed in preparation for natural urushi lacquer.
The koiguchi is cleaned up and leveled.
A fine saw, knife, and paring chisel are used to create a shoulder for the koiguchi reinforcement.
The Nootka Cypress will be contained and kept from splitting by the surrounding horn material, and the wood keeps the horn from contacting the blade.
The raw material comes from some reclaimed carved buffalo horn souvenirs of Canada left over from the 1980’s.
Both sides are flattened by carving and then sanding on a granite plate, and then a kiri is used to create starting points for the opening.
Files are used to enlarge the opening to fit exactly and snugly over the wood core at the koiguchi.
A knife is used to scrape the centre down to the thickness of the shoulder, leaving a hollowed mouth to ensure a tight seal.
The corners are sawed off and a file is used to shape the outside profile.
The surface is smoothed by sanding.
Finer grits begin to soften and polish the look of the surface. Later in the process it will be permanently attached with nori-urushi, a mixture of natural urushi lacquer and rice paste glue.
Reclaimed copper wire is forged to dimension and then bent into a ring.
A small sleeve with pointed ends is formed from the wire to serve as an interface between the ring and the wood. A textured copper plate is cut and forged from reclaimed water pipe and bent to match the curve of the saya.
A test fitting with the plate to determine the proper size for the ring.
A small keyway is created with chisels and kiri. The sleeve for the ring will be locked into the wood here and fixed with nori-urushi, a mixture of rice paste glue and urushi lacquer.
The first layer of natural urushi lacquer is applied and wiped off while wet to seal the wood. It is cured overnight or until dry.
The second layer, in black, is applied thinly with a brush and allowed to cure for a day or two.
Once fully cured, the uneven areas are smoothed and polished with 1200 grit wet paper and fine charcoal.
The third layer is applied sparingly with a brush and then steel powder from the rough polish of the blade along with a few of copper from the habaki are sprinkled in while wet. It is allowed to cure for two days and the excess powder is removed. Some areas are left unpainted to allow the smooth black layer to show through, giving the appearance of a hari bori urushi design.
The fourth layer is applied to saturate the steel powder and then the excess is wiped off. It is cured for three or four days due to the depth of urushi in the steel. After this, two more layers will be applied sparingly and wiped off (fukiurushi) to darken and seal the surface. The resulting pebbly matte finish is a form of ishime-ji (stone-face texture).
Polishing the blade on natural Japanese waterstones to reveal the suguha hamon and utsuri.
Mizukage is visible here, beginning farther in from the hamachi as is sometimes seen in old style blades and known as yakiotoshi.
All completed koshirae parts waiting for final assembly. The kashira and koiguchi are a tight press fit but will be permanently fixed using nori-urushi, a mixture of sokui and urushi.
Hand stitching an antique silk obi sash into a koshirae bukuro storage bag.
More information on the finished work: