Introduction: The Coolest Knife You Have Ever Seen (Made Out of Trash)

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About: I enjoy working with my hands and making stuff. I am unfortunately, on a hiatus from making Instructables due to moving to Canada from Angola, Africa, which is where all my tools were located. Hopefully, I wil…

This kirdashi knife is super simple, easy, and quick to make. It looks awesome and works great for cutting paper, leather, and for marking wood. All you need to make to make this epic knife are common tools, old hacksaw blade, and some trash.

Step 1: Supplies, Tools, and Materials

Tools you need for this instructable:

Trash you need

  • Curvy bit of green wood for the handle
  • Old Hacksaw Blade


Step 2: Making the Knife Blade

Get your hacksaw blade (first pic), lay a ruler across it, and draw an angle so that the saw teeth are on the top (photos 2 and 3).

Make a mark about 95mm from the tip, (photo 4) then stick the hacksaw blade into your clamp and cut it at the 95mm mark (photo 5).

Put the part of your blade that you marked the angle on, stick it into a clamp, (photo 6), and cut along your angled line (photo 7).

Step 3: Cleaning Up the Cuts Using a Bench Grinder

You probably notice that the cuts you made with the angle grinder in the last step are rough and have a lot of burrs. So, now steps in the angle grinder's big brother, the bench grinder (photo 1).
You can see in photo 2, I needed to clean up the angled cut and slightly adjust the angle. You can see what it looked like before I used the bench grinder (photo 2) and what it looked like after I used the bench grinder (photo 3).

There is one last thing you should do before you move on to the next step, and that is grinding down some of the saw teeth on the back of the hacksaw blade. This will help the knife look really tidy. The red box in photo 3 shows roughly how much of the teeth you should grind off. Photo 4 shows the blade after I finished cleaning up the cut and grinding down the saw teeth on the back.

Step 4: Getting the Vine for the Handle

Find a stick/vine for the handle of your knife, they should have the same diameter as the width of your hacksaw blade. I found two good vines growing up a tree (photos 1+2), I suggest getting more then one beacuse if you mess one up you have another.

Get your vine pieces, figure out which part is comfortable to hold, mark about 3cm more on each end than you think you will need, and cut them (photos 4, 5, and 6).

When you have done that, that put them in a pot and cover with water (they may float depending on the type of wood you use). Once the water is boiling, set a timer for 1 hour. You might need to add more water as it evaporates. You need to boil green wood (wood that has not been seasoned yet), otherwise the wood will not dry evenly and it will start to crack and warp and most likely ruin your piece of wood.

Once you are done boiling the pieces, remove them using tongs and put them into the sun until the outside of the wood is dry.

Step 5: Cutting the Blade and Groove

Carve off all the bark so it is just bare wood, it doesn't need to be perfect (photo 1). If you got two sticks, choose which one you are going to use for the handle. I chose the one on the left in photo 1+2 because it was longer, looked nicer, and fit my hand better than the other piece of wood.

Get your piece of hacksaw blade that has the angle cut into it and hold it next to the end of the stick you want the blade in. The end you want to put it in needs to be straight enough so you can stick the tang of the blade in it least 2cm or more (the farther the stronger).

Pick which end of the handle you want to put the blade in, hold the blade beside it and draw a line on the blade where the handle starts to curve (photo 3). Draw another line on it at the end of your handle (photo 4). Stick the blade in a clamp and cut it at the second line using your angle grinder (photo 5). Draw a line straight up, and down on the handle where your thumb sits when you hold it (photos 6+7). Put the handle in your clamp with the end where you drew the line sticking up, so that the end of the handle is as high as the first line on your blade (photo 8).

Get a saw and cut along the black line until you hit the clamp (photos 9+10). Before you take the handle out of the clamp, stick the blade in the groove and check that you have cut the groove deep enough. I had to cut my groove slightly deeper (photo 11+12). Take the handle out of the clamp.

It should look like the 13th photo by now. Remove the blade from the groove and start sanding it with 150 grit sandpaper (photo 14). I highly recommend putting your random orbital sander in a clamp and using it as a disk sander. It will be a lot quicker than sanding by hand (photo 15). Sand until you have removed all the carving marks and the wood is smooth. Don't start sanding it with finer grit until you are done the next step.

Step 6: Gluing the Blade Into the Handle

Put the your blade into a clamp (make sure it is metal) so that the space between the two lines is showing (photo 1). Heat it up bright red using your blow torch, then let it cool down slowly to room temperature (photo 2).

With a centre punch make a divot right in the centre of the space between the two lines (photos 3+4). Get your drill and a metal 1/8 drill bit and drill right in the centre of the divot you made (photos 5+6, I was’t able to drill completely through the tang of mine beacuse I ran out of gas for my blow torch).

All you have to do now is glue the blade into the handle and you are done making the knife. I use expanding Gorilla Glue for almost anything that needs to be PERMANENTLY stuck to anything else. When you use it, I recommend using some disposable gloves. If you don't and you get glue on your hand(s), dirt will stick to them and your skin will look black (kinda gross).

Dip the end of the handle with the groove cut into it into some water, shake off the excess water, and smear a LITTLE BIT of glue on the blade (photos 7+8). It expands 3x to fill all the cracks and crannies (I smeared on a lot for illustrative purposes and I forgot to wear gloves). Shove the blade into the groove (make sure you have it positioned the way you want), wipe off the excess glue with a damp cloth, (I sprinkled the end of mine with a bit of saw dust so that it wouldn't stick to the clamp, which is why it looks dirty in photo 10). Stick the handle into your clamp, tighten the clamp and wait a couple hours before you take the handle out.

Step 7: Final Sanding, Putting on the Finish, and Sharpening the Blade

Take your knife out of your clamp (photo 1) and sand off all the excess dried glue using 150 grit sandpaper until there is only bare wood (photos 2+3). For the final sanding get some 220 grit sandpaper and sand and sand the whole handle. It should feel as smooth as glass (photo 4).

Wipe the handle off with a damp cloth or paper towel and let it dry thoroughly.

I used white mineral oil (butcher block oil) to finish the handle (photo 5, you can use any finish you want). To apply the mineral oil, get a clean paper towel and put thin coats on your handle. Wait about 10 minutes between each coat so that the mineral oil can sink into the wood. When the wood stops absorbing the oil, you have put on enough (put on 1 coat each month to stop the wood from drying out). Wipe off any excess oil (photos 6+7).

For sharpening, Kirdashi knives traditionally are single beveled which makes them super easy to sharpen and very tough. If you are left handed, the bevel needs to be on the left side of the blade. If you are right handed, the bevel needs to be on the right side of the blade. I used a 400 grit diamond stone for making the bevel. I then used a 800 grit stone to get it razor sharp (photos 8). I made a 17 degree bevel using my 400 grit diamond stone, and once it was sharp I moved onto my 800 grit ceramic stone to get it razor sharp (photos 9+10+11).

Step 8: Glory Shots

I am super pleased at how this knife turned out it looks awesome (in my opinion) and works great, for somthing made out of stuff most (uncreative) people think is trash.

Trash to Treasure Contest

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