This began as an old Black Diamond brand flat bastard file. Like this:
Of course, there are other ways to get the metal necessary to craft a blade, such as an online knife supplier like texasknife.com, but I wanted to see if I could be more creative. Besides, if I utterly failed it wouldn't cost me a dime. If you decide you would like to use a file like I did (and many others on the internet) then you will need to get your hands on older files. The reason is simple, older files contain carbon throughout their structure whereas newer files only contain carbon on the surface level. In order to create a strong, sharp, long lasting blade you will need high carbon steel through and through. Older files provide this. One major difference to using a file vs. purchasing your steel from a supplier is that the file will need to be annealed before beginning the process. This is to soften the metal so that you can work with it. Believe me, these old files are strong as hell! Conversely, the knife supplier will provide you with steel that has already been annealed, thus saving you this step. OK, enough about knife suppliers. So how do I know if I have found a file that has high carbon content? I'm not an expert in metallurgy, but the easiest way I know is to clamp the file in a vise (with just the narrow tip sticking up), slap on a pair of safety glasses and give it a lateral whack with a hammer. Did it break? If you answered yes, then you have a winner. If it bent, well ...it's back to the pawn shop with you. Now that you hopefully have found a good piece to work with, it's time to begin the process. The first thing you need to do is anneal the file. The bad news is you need a forge to do this. The good news is.... Here's mine:
Pretty gnarly, isn't it? There are many ways to make a forge. Some are better than others. I had some old bricks, partially burned logs, starter fluid, and 100' extension cord, and shhh my wife's hair dryer. What you are trying to accomplish here is a tiny recreation of the pits of Hell. You need to heat the steel to ~1000*F to where glows red hot, and then to allow it to slowly cool back down to room temperature. This releases the initial heat treatment and gives you a nice soft piece of metal to work on (your blades and drill bits will thank you). You will need to make a small brick fort, pre-burned coals from the bottom of your firepit, some lighter fluid (to help get this thing going) and a long lighter or match. Once you build your little fort and stuff it with coals, soak the coals in lighter fluid and ignite the coals with your long lighter or match. Use your wife's hairdryer (at your own discretion, don't tell her I said it's OK) to stoke the fire. You can then place the file into the fiery cauldron with a long pair of pliers -be sure to wear gloves! Now that the blade is in the fire, keep hitting the whole mess with air from the hairdryer. What you are looking for is a bright red glow uniformly across the entirety of the file. Once this is achieved, using extreme caution, remove the file with your pliers and gloves and place it somewhere to cool off slowly. Sneak your wife's slightly melted, somewhat campfire scented hairdryer back into the drawer. Once the file is cooled, the annealing process is complete. Your file is now ready to be worked. The first thing you will need is to design and create a template (or you can download them from the internet, like these). I used a piece of paper, a pen, and a few drawing aids to help with making precise circles. Here is what that looks like:
My technique was simple, trace the file with a pencil and then draw your knife within the confines of that traced edge. Then cut it out like so:
Place your template on a piece of wood that matches the thickness of your file. In this case, mine was ~1/8". Glue your template to the wood and, when it dries, cut it out with a jigsaw. Like this:
This wooden template will serve as a guide to shaping the knife. Here is what mine looked like after some serious grinding and cutting:
Now that you have your basic shape, you can start to taper the edge so it looks like a real knife and not a Hollywood prop. This is what I had after hitting it with the belt sander a bit:
I was getting pretty excited by this point! You have some options at this point, you can create several different types of edge grinds depending on what you plan on doing with this particular knife. Make sure that you leave about 1mm of material thickness at the cutting edge. This is to ensure that this portion does not warp during heat treating. You will remove the remaining material just before the sharpening process. Now that you have cut out the shape of knife you prefer, shaped the edge grind -remembering to save 1mm of material at the edge you are ready to begin the heat treating process. Shiny!
I'm afraid it's back to the fiery cauldron. Basically, repeat the exact same steps as you did in the annealing process, only this time, quench the red hot glowing blade in used motor oil. You have to do this quickly, do not hesitate or stare at the pretty glowing knife. Drop it in the oil immediately. If you did find yourself in awe of the glowing mass, no worries, simply drop it back in the forge for another 5 minutes or so before pulling it back out (red hot) and quenching it. Here's an extreme closeup of my process:
Once the knife is quenched, it will be covered in some nasty scales from scalding the oil. It is best to remove these with sandpaper before the final heat treating process. Note: the final heat treating process should begin within an hour of quenching. So make sure you sand that crap off fairly quickly. With most of the scaling sanded off you are ready for final heat treatment. To do this, you will place the blade on a cookie sheet and place it in the oven for ~2hrs. The temperature you set it at will determine the final hardness of your knife. Don't get too caught up in the science of this. I set my oven at 400*F. I set the timer for 2hrs and went on to other things to keep from pacing back and forth in front of the oven. Here is what my knife looked like after 2hrs at 400*F:
Fresh out of the oven. Heat treat completed. It has a golden hue indicative of the 400*F temper. Next, I cleaned it up, cut the 1mm of material down to an edge, and began the polishing process.
I also decided to add a couple of functional serrations for fun. The polishing process I used was to create a nice finish without going crazy with it. Since this particular blade will see a lot of use, I stopped at 1500 grit sandpaper. Here is what I did: Sanded the surface longitudinally with 100 grit. Sanded the surface longitudinally with 220 grit. Sanded the surface longitudinally with 320 grit. Sanded the surface longitudinally with 800 grit. Sanded the surface longitudinally with 1500 grit. This is what it looked like:
You can make out the teardrop camper hatch I'm building in the reflection. There are an almost infinite number of choices for the handle. I chose to do what is called a strider wrap with paracord. I don't have any pics of the process, but here is the video I watched to perform this wrap. Here is the final product one more time:
That's basically it. I hope this rudimentary post inspires someone else to try this out for themselves. Cheers, Brandon