TRANSFORM A VINTAGE FILE INTO A CELTIC DAGGER
You don’t need a forge to make a knife.
Agood friend of mine, Paul Kish, mentioned that the next step in his journey to learning blacksmithing was to make a knife from a file. I knew this would be something American Survival Guide readers would find interesting, and he agreed. So, with Paul’s permission and his able assistance, here is how he went through the process.
This Celtic dagger is the first knife he has attempted on his journey into blacksmithing.
It’s crafted using only a 1-inch belt sander and a Dremel-type grinding tool. No forging, annealing or hardening was needed for this project.
What follows are the six basic steps Paul used to turn the file into a nice, Celtic-style dagger.
NO FORGING, ANNEALING OR HARDENING WAS NEEDED FOR THIS PROJECT.
Step 1: Pick the Right File
Paul started this project with a vintage Bell Systems axe-sharpening file, but any file will work—as long as it is a flat file with a wide handle. The type of teeth on the file doesn’t matter either, because you are going to grind them off. He decided on this one, because the full handle makes for a nice, wide tang. A file with a rattail handle, one that narrows, will also work, but it will be harder to fit to the scales of the knife handle.
Another reason Paul chose this file is because it was an older file. He had heard that modern files are often only hardened on the outside, so be careful. If the sparks coming off the file change as you go deeper into the metal, you are probably hitting soft metal.
Step 2: Smooth and Shape Your File
Once you have selected your file, it is time to put on your protective gear and get to work. Attach your grounding strap to something metal—and to yourself. Paul didn’t use one at first and got shocks in his hands about three seconds apart the entire time. It’s generally not especially dangerous, but it got old really fast.
Using the 1-inch belt sander, begin removing metal to make the rectangular file into a pointed blade. You can do this by eye; alternatively, if you want a specific shape to the blade, you will want to mark the outline with a pencil or felt-tip marker.
Once you have the shape you are looking for, you can work on grinding off the file teeth. The file is hardened steel, so this will take awhile. Be patient, because rushing your work can result in an uneven thickness to your blade.
With the teeth removed, you can now start curving the flat down to make the cutting edge.
IF THE SPARKS COMING OFF THE FILE CHANGE AS YOU GO DEEPER INTO THE METAL, YOU ARE PROBABLY HITTING SOFT METAL.
ATTACH YOUR GROUNDING STRAP TO SOMETHING METAL— AND TO YOURSELF. PAUL DIDN’T USE ONE AT FIRST AND GOT SHOCKS IN HIS HANDS ABOUT THREE SECONDS APART THE ENTIRE TIME.
Take care shaping the cutting edges. You want to get them close to sharpened, but don’t go too far. Better to leave a flat “edge” of 1/8 inch that you can sharpen by hand later rather than taking off too much and then having an odd-shaped blade.
Step 3: The Tang and Guard
Paul wanted to put a brass guard on the knife, so he purchased some solid brass line cleats from a local boat store.
To make the slot in the cleats for the knife’s tang to go through, you will need to remove the brass between the screw holes. The best way to do this is to use a round- or triangular-shaped file. Start in one hole and work your way across
to the other hole. A line drawn between the two holes will help you get a straight slot instead of a curved or wavy one. Go slowly with this, because you don’t want to remove too much metal. If you make the opening too large, the guard might not fit snuggly.
Once you have your slot in the guard, start grinding the tang so it will fit into the slot you cut in the guard. Paul got the guard to slide just over the base of the blade.
If you don’t like the size of the cleat/guard, grind it down to the look you want. Brass is very soft, so go carefully here. Use a fine-grit belt to polish it up.
If the guard moves around against the blade too much, you can still continue to the acid-etching step; just secure the guard with J-B Kwikweld when you attach it to the handle later on.
Step 4: Acid-etching Your Design
It is time to apply your design to the blade.
Put your design on paper. Paul chose a style of Celtic braid so it could follow the blade. You will need to transfer or freehand it. Regular pencil will show up on the metal and is the easiest way to apply the design.
Use a metallic Sharpie to apply the image to one side of the blade, and then put the mirror image on the reverse side. Paint the parts you want to stay shiny with the Sharpie. Cover the blade edges and tang with electrical tape so they do not get etched by the acid bath. Because the metallic Sharpie and electrical tape block the acid from reaching the metal, you are basically creating a negative image of the finished design.
Next, put on your eye protection and Nitrile gloves. In a well-ventilated area, pour one part muriatic acid (e.g., 1 pint) into a plastic container (Paul used a plastic paint roller tray). Then, add two parts (2 pints—which equals 1 quart) hydrogen peroxide to the muriatic acid. Don’t add the acid to the peroxide, because it will bubble up and splash acid.
Carefully place the blade into the bath.
The longer you leave it, the more defined the etching will be. Paul left his knife in for around three hours.
Once it’s done, rinse the knife thoroughly to remove all the etching solution. Use 300-grit wet-dry sandpaper (under water) to gently remove any remaining metallic marker.
A note on the blocking material: The metal in the metallic Sharpie will be eaten by the acid, leaving a “weathered” or “ancient”-looking patina. For cleaner, more pronounced lines, fingernail polish and remover work very well.
Step 5: Handle and Scabbard
Paul chose walnut for his knife handle, because he liked the natural color when wet.
Cut your wood or other handle material into suitable sizes for the handle and scabbard. Trace out your tang with the guard in place; do the same with the blade without the guard.
You will need to sand a spot for the guard to sit in later.
Start grinding the wood away until you get to half the thickness of the tang for the handle. You will want it to be a little more than half the thickness of the blade for the scabbard. Test-fit them often until the two pieces of wood meet without gaps.
The scabbard should allow the blade to be drawn and inserted smoothly. Make sure there is extra room for the point to go into, because you will still need to sand things down.
Once your fit is good, fit the guard to the blade, fill both sides of the handle with epoxy, and clamp tightly, with the blade end pointing up. If you have it pointing blade down, the epoxy will run out of the handle and all over the blade. If there is space between the guard and blade, fill it with a little J-B Kwikweld.
A note of interest for those who want to make a knife they will actually use as a cutting tool: As described, this dagger is suitable for decorative use, such as costumes or wall displays. If you only attach the handle to the tang with epoxy,
the handle might come off in hard use. If you intend to use it hard, drill two or three holes through one handle scale, through the tang and out the other handle scale. Then, fix pins in the holes you just made and sand them flush.
For the scabbard, put a thin line of epoxy on the mating surfaces and clamp them, point end up, until set. You don’t want epoxy setting up on the inside, because this will block the blade. Once the epoxy is set, sand the wood to the shape you want. On the scabbard, sand, carve or grind notches for the guard to settle into. Use progressively finer grit to smooth things out.
Step 6: Detailing and Finishing
Now that you have the blade, handle and scabbard completed, it’s time to add some embellishments to your dagger. Paul used 4mm leather stripping and an old dirk frog (basically just a leather loop) to dress it up. You can do whatever you want: For instance, carve a pattern into the wood, stain it a different color, embed real or synthetic gemstones in the handle and scabbard, or inlay it with silver or gold wire. Once it’s to your liking, finish it with polyurethane to protect it and keep all the leather secure.
Your dagger is done. If your file was made from good steel that is hard enough to take an edge but not so hard that it is brittle, you should be able to sharpen it to a pretty fine edge, if you are so inclined. If the quality of the steel isn’t that good, you will still be able to put an edge on it, but it might be best for ceremonial or costume use.
One final—but important—note: Remember to check your local laws regarding the length of knives you can carry with you.
REMEMBER TO CHECK YOUR LOCAL LAWS REGARDING THE LENGTH OF KNIVES YOU CAN CARRY WITH YOU.
Right: There are many types of Celtic designs to choose from. This one is more intricate than Paul’s and is better suited for wider blades.