Making an Outdoor Knife

The Japanese swordsmithing tradition has been in place for generations and many of the design elements have been tested and refined for centuries. With careful study and practice, this can be a solid foundation for today’s bladesmiths and knifemakers to build their work upon.

This article will provide an overview of the process and cover some of the considerations for implementing nihonto geometry and construction into a fusion style knife. There will not be room to fully discuss the details of mounting that have been touched on elsewhere, but it is hoped some of the main points will assist in the successful engineering of a knife in this manner.

Hizukuri: Forging the Blade
Ara-Shiage: Shaping the Blade
Yaki-ire: Hardening the Blade
Tsuba: Making the Guard
Nakago: Carving the Handle
Tsuka: Shaping the Handle
Final Assembly


Hizukuri: Forging the Blade

Island Blacksmith: Hand forged knives from reclaimed shear steel.
The raw material for this blade comes from a reclaimed shear steel leaf spring taken from a horse-drawn carriage and estimated to be a century and a half old.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The steel is forged into a rectangular bar called sunobe. The sunobe determines the volume of steel allocated to the blade and tang and largely the final dimensions. The tip is cut at a 45 degree angle and filed smooth to prevent cold shuts. Note that the edge is facing up in this photo.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The tip is then forged to the opposite position, running the layers of the steel along the edge. Note that the edge is still facing up in this photo.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The peak of the spine is forged to shape next, followed by the bevels. A thin layer of water on the anvil creates steam explosions that clean the forge scale off the steel, preventing it from building up and marring the surface.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
Any excess is hot cut from the end of the tang. At this point all of the shaping has been done with the hammer alone.

Ara-Shiage: Shaping the Blade

Island Blacksmith: Hand forged knives from reclaimed shear steel.
Using a file, the profile of the blade is cleaned up and the machi are made true.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The bevels are cleaned and shaped using a hardened steel scraper called a sen.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The rough scraped surface left by sen.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
Filing and drawfiling are used to true and smooth the surface left by the sen.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The rough filed surface left by drawfiling. At this point the edge is left 1-2mm thick in order to decrease the chances of warping and cracking during hardening. A coarse stone may also be used to ensure the surfaces are a straight and true as possible before yaki-ire.

Yaki-Ire: Hardening the Blade

Island Blacksmith: Hand forged knives from reclaimed shear steel.
Applying the clay layers in preparation for hardening the steel (yaki-ire). The thicker layer insulates the steel, causing it too cool slower and form pearlite/ferrite. The thin layer on the edge increases the surface area, causing it to cool faster, forming martensite.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
A blade is born. The steel has hardened successfully without cracking, a file will not cut the edge at all but slides off without biting.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The clay is removed, the edge, straightness, and shape of the blade are inspected. Then the steel is cleaned and tempered to remove some of the internal stress.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
An inspection polish with a coarse waterstone reveals a distinct hamon marking the division between the tougher blade and harder edge. The blade is shaped on coarse stones until it reaches final geometry and then all other mounting work is done before the final polish.

Tsuba: Making the Guard

Island Blacksmith: Hand forged knives from reclaimed shear steel.
The guard is forged and then drilled and chiseled to create the opening.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The opening is carefully enlarged and shaped to fit the blade, and the back is flattened on a diamond stone. Once the handle block is ready for shaping, it will be sawed and filed to an oval profile.

Nakago: Carving the Handle

Island Blacksmith: Hand forged knives from reclaimed shear steel.
The Wenge accent is drilled with a kiri and carefully carved and filed to fit tightly to the tang and flush with the back of the guard. This greatly increases the complexity of carving and fitting and is not recommended on a first attempt.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
A block of Sapele is sawn in half and the outline of the tang traced on the inside of the omote half.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The tang sits halfway in on the spine side but flush on the edge side.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The inside of the ura half is carved, checking often to ensure a snug fit an proper alignment with the omote block. The tang sits halfway in on the spine side but not at all on the edge side.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
The pieces fit and are ready to be glued together and tightly wrapped and wedged until cured. In this case a strong adhesive made from rice paste and urushi will be used.

Tsuka: Shaping the Handle

Island Blacksmith: Hand forged knives from reclaimed shear steel.
After the glue is fully cured, the handle block can be taken down to size using a hand plane.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
Next the profile of the guard is traced onto the block and the rest of the shaping and carving is done with kanna, chisels, rasps, and kiridashi. After sanding the handle is ready for several coats of fukiurushi, each requiring several days to cure.

Final Assembly

Island Blacksmith: Hand forged knives from reclaimed shear steel.
When all of the components are complete, the blade is given a final polish using progressively finer natural waterstones and finishing with fingerstones to bring out the character and detail of the steel.
Island Blacksmith: Hand forged knives from reclaimed shear steel.
A natural waterstone polished hamon is subtle but can be seen clearly at a certain angle of light. There is also some evidence of the shear steel hada on the surface of the blade.

Island Blacksmith: Hand forged knives from reclaimed shear steel.

Island Blacksmith: Hand forged knives from reclaimed shear steel.

See the full specs of this fusion style outdoor knife: Available Work: Fusion Style Kotanto

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