Intro: Shirasaya (Japanese Sword Scabbard)
So, before we start, I just want to get into what a shirasaya actually is. It's a wooden scabbard and handle designed primarily to protect a blade from damage. Traditionally, they were made from magnolia or ho wood (very soft woods) so as not to dull the edge of the blade at all. In general, they are not designed to be functional as a handle. A separate set of mountings called koshirae are used when the sword is taken into combat or is used, then the shirasaya is placed back onto the sword to protect it once they are done using it.
My shirasaya differ slightly from the traditional route. I make them out of hardwoods, both for aesthetic value and to provide structural support that softwood can't provide. The tsuka (or handle portion of the shirasaya) is designed very sturdily and with grip comfort in mind. This is all so that the shirasaya can provide protection to the blade, as well as a fully functional handle.
Okay, onto the making!
Step 1: Materials & Tools
Here are the things you will need to make your own shirasaya:
*A japanese styled knife with habaki (technically you don't need this to actually make the shirasaya, but it won't be very useful if you don't have a knife to put it on)
*A block of wood that is slightly longer, wider, and thicker than the knife you are using
*Another type of wood for spacers (more on that later)
*A third piece of wood for the peg that will secure the tsuka onto the blade
*Mineral oil for finishing the wood
*Iron wire (for scraping glue out)
*Chisels, this will be the main tool used for carving and shaping the shirasaya
*Abrasives for wood polishing purposes
*Some form of saw for cutting the wood (hacksaw, miter saw, table saw)
*Box cutter or marking knife
*jewelers saw (mainly for spacers work)
*Needle files (mainly for spacers work)
final shaping can be made much quicker and easier if you have a belt sander of some kind
A planer will help make flattening the wood after it is cut easier
Step 2: Cutting the Wood
So I started with a block of walnut that was just slightly bigger than my knife's dimensions. I split the wood right down the center on my table saw, giving me two thin pieces of walnut. If you don't have a table saw, you can use a hacksaw or miter saw to split the wood. Make sure you remember what orientation they were originally in, when you glue them back together the grain should match up the same on both sides.
The table saw left some rough patches and burn marks on the inside of the wood, so I ran it through the planer until the wood was smooth. The ending thickness of each piece ended up being a little over 1/3".
Step 3: Marking and More Cutting
This step is very important! It will basically lay the foundation for the rest of your project, so make sure to take your time here.
Start by approximately centering your blade on the wood. Mark where the back of the habaki is, then use a ruler to draw a line across the wood. Match the marked wood up with your other piece, and mark the second piece of wood. Using some form of saw (miter saw works best), cut the wood along the lines you just marked. You should now have 4 pieces of wood. Mark each so that you remember which piece goes with which piece (pictures 10 & 11).
Now, mark on the knife where the back of the habaki is. Line that mark up with the cuts that you previously made in the wood (see picture 14). Lightly trace the outline of the blade onto the wood. Make sure you are tracing onto the inside face of the wood, the part that I cut with a table saw then planed. This will ensure that the grain matches up when you glue it later. I added a little extra line to mark where the habaki would be if it had been on the blade during tracing (picture 16).
Step 4: Carving the Tsuka
Start by taking a box cutter and make an ~1/8" deep line following the pencil outline that you marked in the last step. I make a little rectangle near the tip to make it easier to carve (picture 2).
Now pull out your chisels. I made a special set of chisels specifically for carving shirasayas, but a standard wood carving set from a store should do the trick. Start to carve the profile of the blade's tang into the wood. The idea is to get a perfect fit that follows all the tapers in the tang. Carve so that one side of the tsuka covers half of the thickness of the tang, and the other side of the tsuka covers the other half of the tang. Then when you put them together, it should make a perfectly tang-shaped hole. The carving is probably the most difficult part of the entire process, so don't be worried if it takes a couple of days for you to get it right the first time.
When you feel like you are getting close, clamp the two halves of the tsuka together. Coat the tang in a light coating of mineral oil and push it into the clamped tsuka as far as it will go. If it goes in all the way with a tight, wiggle free fit, you're done! If it stops before going in all the way, unclamp the tsuka and you should be able to see dark spots in the wood from the oil that was on the tang. These are basically the raised spots that are stopping the blade from going in all the way. Chisel those spots, then reclamp and try again. Keep repeating this until you get a tight fit, then move on to the next step.
Step 5: Carving the Saya
Carve the saya (scabbard) the same way that you carved the tsuka. Once you get the blade to fit semi tightly in the scabbard WITHOUT the habaki on, rest the habaki on the mouth of one side of the saya. Using the box cutter, mark a line where the front of the habaki is. Start carving the habaki contour in. The habaki should be extremely tight fitting. Notice how I can hold one half of the saya upside down with the habaki in it and it won't fall out. Clamp both sides of the saya together. The blade should slide smoothly and easily in, and the habaki should slide smoothly but firmly into the saya.
Step 6: Drilling and Gluing
I missed a couple pictures here... Sorry guys :(
Basically, what I did was drill a pilot hole in one side of the tsuka that will be filed out later. Take the right side of the tsuka (when the edge of the knife is down and the point of the knife is facing away from you, the right side of the tsuka is the one that would go on the right). Place the tang of the knife in the tsuka and drill a hole that is approximately half the size of the hole in the tang through the wood. You should now have a SINGLE tiny hole through only ONE half of the tsuka.
Now, coat the face that is going to be joined on the tsuka with wood glue. try to not get glue into the place that you carved in. Clamp the two halves of the tsuka together with the knife tang inside. Then, pull the knife out while keeping the two halves clamped. Take a small piece of wire and scrape as much glue out of the inside of the tsuka as you can. Leave it to dry. Repeat everything in this paragraph to glue up the saya portion of the shirasaya. I DO have pictures for this part, so hopefully they will help with the gluing portion!
Step 7: Spacers
You may find that your tsuka and saya don't fit completely flush to each other. This is where spacers come in. Put the tsuka and saya on. If they don't quite fit together, use a protractor to check the angle that the saya is off by. The mouth of my saya was about 1.25 degrees off of flush with the tsuka. Using a miter saw, I cut ~1/8" off the tsuka at 90°. Then I set the miter saw to 88.75° and cut 1/8" off the mouth of the saya. Now the angle that they come together is right, but there is an 1/4" space between the mouths of the tsuka and saya.
Now I take some cocobolo stock and cut an 1/8" sheet off. I sawed it into a couple pieces so that I had two pieces that were just slightly bigger than the mouth of the saya.
Now you have to saw a precise hole for the tang to fit through on the spacer. I take a sheet of paper and fold it over the mouth of the tsuka. Then using a box cutter, I cut out the hole for the tang into the paper and cut out the rectangle with the hole in it. Take the square of paper and trace it onto one of the spacers. Clamp the piece down and drill a hole through it WITHIN the outline you just traced. File the hole out with needle files so that it is squared up at the top. Then, use a jewelers saw to cut out the rest of the outline. Use files to refine the shape so that it fits around the tang tightly. Glue it onto the tsuka with the knife in, then pull the knife out. Scrape as much glue out as you can. Now for the saya spacer. It is pretty much the same thing, except this time you should trace the back of the habaki onto the spacer.
Step 8: Shaping
Traditionally this part is done entirely with hand planes and chisels. But I normally use a belt sander to speed up the process.
Start by sanding the spacers flush with the tsuka and saya. Then, put the knife in the tsuka and put the saya on the blade. The mouths should fit together tightly, but the sides may not be quite flush. Go back to the sander and sand the shirasaya with the knife in it until the tsuka and saya are flush to eachother, as shown in pics 9,10, and 11.
Here's where I start planning out the shape of the shirasaya. I went with a traditional octagonal shape here. I start by tracing the end of the saya onto a sheet of paper. Then I mark the places that I want to sand off. I cut out the rectangle and trace it onto the saya end. Then it is back to the sander where I sand in the octagonal shape. the tsuka should also taper slightly from the mouth of the tsuka to the end of the tsuka. Basically, it should look more like a trapezoid than a rectangle. Also, the ends of the tsuka and saya should be slightly rounded. I tried to draw in exaggerated lines in picture 24 to try to show what I mean a little better.
Step 9: Polishing and Oil
Using extremely fine sandpaper, sand all the faces of the saya. I started at 1000 and worked my way up to 2000 grit. Take care not to roll the crisp geometry lines. When you are done, the wood should be very, very smooth.
Now go and coat the shirasaya with mineral oil. Coat the face of the spacers, but try not to get the oil inside the shirasaya. I generally leave it overnight so that the oil will soak in fully. Wipe the residue off once it has fully soaked in.
Step 10: Mekugi
This is the final step. The mekugi is a small, tapered wooden pin that secures the tsuka to the tang. The cool part is that the mekugi can be removed and the entire knife can be taken apart for maintenance and sharpening.
Start by filing out the hole that you drilled a couple steps ago. It should be flush with the hole in the tang, then taper out a little. Once you file that side in, drill another pilot hole, this time through the other side of the tsuka. then proceed to file in the taper. my hole ended up being 1/8" on the left side of the tsuka and a little over 1/4" on the right side, smoothly tapering from one side to the other.
Now you need a small little piece of wood for carving the actual mekugi. Mark the diameter on each side that you want the pin to be, then proceed to whittle it down to size. once you get close, you can use sandpaper to clean up the shape. The mekugi should slide firmly in with light hammer taps. once it is all the way in, mark how much you need to cut off and tap it back out. Tap the pin back in and use needle files to bring the mekugi almost, but not quite, flush. Don't file it completely flush so that you are better able to tap the pin in and out in the future. lightly sand the surfaces of the pin, then oil it. The oil will cause the wood to swell slightly, providing a very tight fit.
Step 11: You're Done!
I put a final polish on the blade and habaki, and now the entire knife is finished! Take a look at that beautiful hamon :-3
The blade should be able to be easily and smoothly drawn, but the saya shouldn't have any risk of falling off when it is sheathed.
Well, I hope you enjoyed! I will be entering this in the woodworking contest, please vote for me if you liked this instructable. :)
I will be watching the comments so feel free to post any questions and I'll do my best to answer. Also, I'm debating between a couple of topics for my next instructable, tell me in the comments which instructable you all would prefer to see:
*Japanese Blade Forging
*Instructable for the chisels shown in this instructable
*Custom wooden guitar picks with metal inlay
*High carbon steel lawnmower blade mod
Thanks for reading!