How to Make a Knife That Comes Out of an Armband
- 1). Design your blade. The most important part of any knife is the blade. To achieve the best results, consider the purpose of your blade.
Most knives kept in an armband are used as throwing knives, which feature minimal handles and short or thin blades. Average length for these types of knives would be 4 to 8 inches. - 2). Draw the knife on a piece of cardboard, then cut it out. Since it will be stored in an armband, make sure the knife is not too long for your arm. You will need to be able to carry the knife comfortably while still maintaining full range of motion.
Throwing knives are more delicate than other knives and often have flat handles the same width as the blade so they will not spin when thown. - 3). Tape the knife template to the piece of steel.
- 4). Trace the outline of the knife onto the steel using a permanent marker.
- 5). Clamp the piece of steel to the work bench. Be careful to clamp it tightly so that it will not move while you are sawing the outline. Put a piece of cardboard or sandpaper between your work piece and the vise to prevent scratches.
- 6). Create a small groove at each point where the template outline meets the edge of the blade using the triangular file. This will keep your saw from slipping as you begin to cut and scratching the metal or cutting too much steel away.
- 7). Cut out the knife from the surrounding steel using the hacksaw. You should cut just outside the black template lines, to allow yourself room to make mistakes.
- 8). Use a chisel as leverage to pry the template away from surrounding pieces. This will make it easier for you to cut.
- 9). Use the coarse half-round file to smooth away all evidence of the black marker line around the edges of your new knife.
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Smooth the edges further with the smooth round file. Make sure no sharp edges remain on the handle, and consider rounding all edges on the knife for a comfortable grip. - 11
Sharpen both sides of the blade slightly using first the coarse file, then the smooth. The most important part of a throwing knife is the tip, not the edges, because it is not used for slicing.
Gradually increase the sharpness of the blade as you approach the tip. Only the tip needs to be sharpened to a point so that it will penetrate the target when thrown. Don't focus all your time and energy on creating sharp edges. - 12
Balance the knife. The knife should balance on the edge of your finger at exactly half of its length. For example, if the knife is 4 inches long in total, balance the knife with your finger 2 inches from the tip. If it stays level, the blade is balanced and will fly straight when thrown. If the blade leans one direction or the other, use the file to smooth the knife edges until it is balanced. - 13
Polish the blade using various grades of sandpaper, beginning with the most coarse grade and progressing to the finest. Use a medium-grade sandpaper to create a satin finish. To create a mirror polish, continue polishing with fine-grain sandpaper. - 14
Purchase an armband sheath that your new knife will fit into, or make your own.