How to Make a Knife from a File: Your Guide to Crafting the Best Cutting Tool
Every outdoorsman needs his own set of tools. But because you can get all of the necessary equipment for every outdoor activity you want right from a shop or an online seller, there’s not much of a “connection” being formed between you and your tools.
As a person who goes outdoors a lot, have you ever felt the need to have a set of tools that’s perfect for your specific needs? Have you ever held a knife that fits so perfectly in your hands that you can use it with ease, no matter what you use it for?
Knowing every curve and every detail of your tools – you will only have this connection with them if you were the one who created them. You can also get this level of handling if you’ve used your tools for years. But otherwise, you can still master the use of any tool – such as a bush craft knife – by crafting your own. Today that’s what we’re going to do.
We will teach you how to make a knife from a file, using simple tools.
What You Will Need
- Old File
Find out if you’re using the right file by conducting a hardness test: Try to scratch the steel on the surface using a screw or a drill bit. It should be hard to scratch and leave a mark. You don’t want a file that is “case hardened” – meaning the ones that have a softer core made of mild steel. You want an old file that is made of pure high carbon steel.
- Forge and Coal
You will need charcoal for the process known as “annealing”. With it, you will make a small fire to bury the old file in. Keep the fire hot enough for three to five minutes. Afterwards, just leave it alone until it cools down. Allow the fire to go out on its own.
- Two-Part Epoxy Adhesive
- Quenching Oil
- Permanent Marker
You will be drawing a knife pattern of your choice into any piece of paper. Then, with the permanent marker, you can trace it onto the annealed work piece.
During the process of profiling, you will need to secure the work piece into a vice so you can easily cut it.
You will use the hacksaw to cut the rough shape of the knife design you traced. Apply some oil and use long and steady strokes. This should eliminate friction during the cutting process.
- Lubricating Oil
- Kitchen Oven
The kitchen oven will be used for the process of tempering. You will heat the blade to 175-350 degrees Celsius for around two hours.
- Piece of Hardwood
You will need this for making the handle. You can use a piece that’s about 35 x 35 x 100mm. With a drill, you will be drilling a rectangular hole into this work piece in order to slide the knife in later. Once you’ve successfully put in the tang, you can saw this wood into a handle, the shape and size of your preference.
If you can’t get the tang to slide down the bolster, you can hammer it into position.
You will need some sandpaper for refining most of your cuts during the entire process of making a knife.
How to Make a Knife from a File
So we’ve briefly covered everything you’ll need to transform that old file into a knife. Now let’s go over the step by step process on how to get it done.
- Step 1: Designing
The first step in making a knife is designing one. You’ll decide how long, how thick, and how sharp it would be, right from the start. If you want a durable knife, it is advisable that you go with one with a full tang. For those of you who don’t know, the tang is a part of the blade – the long metal part that gets hidden beneath the handle itself. So if you take a knife with a full hidden tang, you will see that the blade extends well into the handle.
- Step 2: Annealing
This step is so that we can mold your file into the knife you want it to be. The process of annealing involves softening the metal so you can shape it later on. Once your old file has cooled within the coal, you are free to move on to the next step.
- Step 3: Profiling
This is where you take your design, trace it carefully around the cooled metal, and then saw off most of the unnecessary parts. Make a rough cut of your design with the hacksaw, and then do some refining with the sandpaper.
- Step 4: Making the Grind
Next, you’ll work on the “bevel,” also known as the grind. This is the cross section of the blade that determines its sharpness. With a caliper, measure the blade’s thickness.
This may involve a bit of math, but use this formula to determine the grind width:
Grind width = T / (2tanα)
T refers to blade thickness and α is the grind angle.
Once you’ve calculated the grind width, mark it out. Next, file in both sides of the blade.
- Step 5: Quenching
You can harden the blade now that you’ve formed the grind. This process is known as “quenching”.
For this step, all you have to do is put the blade back into the coal for about three to five minutes without heating the whole tang. Next, carefully – and quickly – lower the tip of the blade into a container, and then slide the whole thing in. Leave it in there until it has completely cooled.
- Step 6: Making the handle
Mark out holes for the bolsters and then punch a hole for them. For the bolsters you can use the leftover metal from your old file. Now it’s time to assemble your new knife. Slide the front bolster over the tang, put the blade into a vice, and then apply some of the epoxy to the tang. Make sure to put some epoxy on the hole of the wooden handle and the bolsters as well.
Carefully place the rear bolster and the handle over the tang. Let the epoxy settle and you’re ready to refine the whole thing with sandpaper!
Did you like this tutorial? Tell us what you think down in the comments and share it with your friends. Making a knife from a file is a delicate and meticulous process. It’s important to follow each step carefully so that the whole thing comes out perfectly.