Before machine-made files became cheap and expendable, a man who was short on money or materials could make a knife from scrap. This would include old horseshoes, worn-out wagon tires and parts of broken or obsolete machines.
The first step is to anneal the file. This process heats the steel to a bright cherry red and then lets it cool slowly.
Make a Blank
If you’re looking for a low-budget project for your next woodworking endeavor, why not try making your own knife? While it’s certainly not a quick or easy task, it is possible to build a knife from an old file.
The process can be as simple as using a saw to cut your blank out, or as elaborate as sanding the metal and bending it into your desired shape. Whatever the case, the important thing is to remove as much excess material as possible before sanding it down.
Shaping a blade blank is a tedious and time-consuming task. Fortunately, it’s easy to make the task faster by incorporating some basic power tools into the mix. For example, a high-quality angle grinder or metal-cutting bandsaw can help speed up the shaping process while reducing hand strain.
Shape the Blade
You can make a knife from all sorts of stuff, like lawnmower blades, car springs, saw blades and files. Files are usually a better choice for raw material than rasps because they are made out of hardened steel that can be shaped into a blade.
Step 1: Shape the blank into a blade by hammering and forging with the anvil. It may take several hammer blows to get the angle right, but it should end up looking much more like the blade you want.
Next, sand the edge of the blade with descending grits of sandpaper from 100 grit to 400 grit. This is one of the most boring and tedious steps, but it will get your blade ready for a sharp edge.
During the filing process, the blade will probably vibrate, so you can help minimize it by clamping the handle in a vise close to the file. You can also use a piece of scrap wood on the back of the blade to lessen vibrations.
Attach the Scales
Once you have the blank shaped to your satisfaction, it’s time to attach the scales. This is a fairly simple task if you use a two-part epoxy.
Mix up a little of the epoxy and spread it on one side of the knife blank. Place a scale on the epoxy and then tap it into place.
Then you can slide the scale back on the blade and tap it in place to secure it. This can be a little tricky if you have to do it on a curved blade, so be sure to use a good vise.
After the scales are attached, it’s time to drill a hole through the tang and the scale. This will help keep the tang and scale from moving while you work on the blade.
I recommend using a copper ground wire or brass brazing rod for this step. You can find these in a number of hardware stores. These rods are also quite inexpensive compared to the pins that knife supply houses sell.
Finishing Touches
The file blade will need some finishing touches to get it into shape for use as a knife. The first step is to anneal the steel.
This is done by heating it up to a bright cherry red, then dipping it in oil. This process anneals the steel and softens it, making it easier to work on.
Next, shape and sand the handle. You can use a variety of tools to do this, including a sander or belt sander.
Once the handle is shaped, you can attach the scales. You will need some two-part epoxy, about a half-dollar worth of it.
You will also need something to use as a pommel. This could be a candlestick, tee-ball trophy, or something else that looks like it would make a good knife grip.