I had some beech leftover from building the precision standing desk for class and some free time over Memorial Day weekend, so I decided to make a sheath, or saya as it is supposedly known in Japanese, for one of my kitchen knives. The intention was to have a relaxing Saturday taking a break from ‘work’ instead of making the piece in the most efficient manner, so I restricted my power tool use to the initial resawing — all subsequent operations were done using hand tools only.
I picked out an approximately 3″-wide length of 4/4 beech stock I had leftover for this project. It came from a board that had previously been surfaced, so it ended up about 3/4″-thick. To get a nice slip-matched finish between the two halves of the saya, I started by resawing the board into two thinner pieces. I had read a few articles and watched a few saya-making videos that said the ideal saya should be asymmetrical, with most of the blade being inlaid into one half. The sources I came across prescribed this as a matter of tradition, but it makes a lot of sense mechanically too: by burying the sharp edge of the knife in the solid wood of one half, you dramatically reduce the stress placed on the glue joint by the knife trying to wedge it open. To achieve this effect, I split my piece asymmetrically, with the thinner piece about 1/4″-thick.
The next step was to joint the sawn faces flat so they can be glued together down the line. I used a jointer plane instead of the power jointer for this operation. Given the luxury of time, nicely tuned hand tools really are some of the great pleasures of woodworking. The result: beautifully smooth and flat faces without having to worry about washboarding or snipe.
Next, I clamped the two halves together and cut a relief into one corner to accommodate the knife handle and put the blade further into the wood. This is both an aesthetic feature and to provide more wood behind the heel of the blade so that I have room to drill a hole for a retaining dowel if I so choose (I still haven’t decided)
Once the handle relief is cut, it is time to mark off the outline of the blade. I left some additional clearance around the tip of the blade here to protect the often quite fragile tips on these Japanese knives with acute grinds and super hard steel. My plan was to have the saya lightly grip the blade near the spine above the heel, and to make contact with the edge at the relatively thick and strong heel region.
After cutting the blanks to length (turns out I have enough for another saya for my petty knife!), I spent a relaxing hour or so carving the slot for the blade. This part wasn’t as easy as I had hoped for. Beech, for all its excellent machining qualities, is really quite hard and a bit slow to work with hand tools. However, it was incredibly enjoyable to do it by hand (and quite possibly faster, too) instead of measuring the knife and programming a job on a CNC router.
You can see in the image above that most of the blade is buried in this half, with only the rear half of the spine slightly proud, to be accommodated in the mating piece.
The image above shows how most of the insetting happens on one half, with only a little relief towards the rear end of the spine on the mating piece. It is also pretty obvious I badly need to work getting better at holding clean corners with a chisel. I roughed out the exterior outline on one piece before gluing them together, so that I would have a reference for contouring the outside surfaces without having to worry about cutting through into the cavity.
Glue-up and contouring
After a quick glue-up, I started to work on the exterior of the saya. I wanted it to mirror the geometry of the blade, so I worked in a tapered section and a prominent ridge marking the transition to the flat section further up the blade. This ridge is intended as a reference to the shinogi on the actual blade.
A rabbet plane (a plane that can cut right up to a shoulder) made quick work of those tapered sections, and a selection of cute finger planes took care of the rest. A quick progression through a few grits of sandpaper took the surface to a respectable quality and I left it at that for now.
The slot turned out better than I had hoped and the blade sits snugly in the saya. Right now it is secure enough to not fall out even if I hold on to the sheath and shake it around. That being said, the wood is probably going to move a little over time, so I am glad I still have the option of drilling a hole for a retaining pin to keep the blade in the sheath. But for now, I am going to leave it be — I just love the clean, minimalist lines and want to keep it that way.