Making a knife from a file

Once, “out of files to make knives,” as Vladimir Vysotsky sang, any teenager knew how. Today, this skill is almost completely lost. Nevertheless, the need for a good knife made of hard steel, capable of easily cutting various materials and keeping sharp for a long time, is in every master.


If you have an unnecessary file, then you can make a quality and durable knife out of it.

The tool can be bought, but a quality knife is not cheap, and you can always find an old file. Practically everyone can make a knife from a file with their own hands. You just need to follow the technology. How to make a knife from a file, what materials and tools are needed for this? What is the sequence of operations. This will be discussed below. It can be not only a useful tool, but also a good gift for any man.

Preparation of materials

File sizes

The size of the file.

First of all, for the manufacture of a knife from a file you need to find a suitable workpiece. In this capacity, it is best to use a Soviet-made file. It should have a width of 30-40 mm and a cross-section in the form of a flat rectangle (preferably diamond-shaped). The latter will give the blade of the future knife greater strength, but such files are much less common than flat ones.

In addition, for the production of a knife you need to pick up the material from which the handle will be made. It can be a tree, deer horn, bone, leather belt or a set of multi-colored plastic plates. Brass or aluminum rivets and epoxy resin come in handy. The tools will require a vice, a grinder, a sharpening machine, several varieties of emery paper with different grain sizes, as well as a magnet for checking the tempering. You also need ferric chloride to pick up the knife blade, since the file consists of iron that is prone to rust. The etched surface protects against this. It remains only to draw a sketch of the future knife, and you can get down to business.

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Heat treatment of the workpiece

Filament file

In order to make a knife from a file, it must be heated.

The material for the manufacture of the file served as a uniform steel U10, saturated with carbon. It is too fragile and can crack under strong impact. That is why it is possible to make a knife out of a file only when it is exposed to heat, which somewhat changes its properties. The file needs to be heated up to 700 ° С and slowly cooled. This is best done in a burning stove, but you can do with an ordinary gas stove. Since it cannot give sufficient temperature, it is necessary to build a heat shield over the file. As such, any metal plate having a sufficient thickness and area overlapping the file can be used. It should rise no less than 1 cm above it. To do this, you can put a few nuts or bolts on the file plane.

You need to basically anneal only the part of the file that will be the blade of the knife, so you need to skip it. The screen prevents the rapid rise of hot gases, and this speeds up the heating process. Warm up area should be sprinkled with large table salt. If it starts to melt, it means that it is hot enough. The metal must acquire a smooth cherry color and remain in this state for at least 4 hours. After that, the heating can be gradually reduced to complete cooling. When a file is heated in a furnace or stove, it should cool with it. The slower the cooling process, the better. If you cool the file sharply, it will simply crumble.

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Making the shape of a knife, its hardening and tempering

Hardening knife

After you have heated up the file, lower it into the water.

After the steel of the workpiece is released, you can begin to give it the desired shape. It is clamped in a vice, with a grinder, cutting off all unnecessary, and then using a grinding wheel with a coarse-grained circle, they carve a future knife. If the handle is made of patch plates, then for its mounting it is necessary to drill holes for rivets or to cut a groove by the grinder. After that, you can begin to quench. The steel is heated to a bright red color, while the blade must be evenly heated everywhere except the base of the blade. There it should be heated almost completely. The degree of heating of the handle does not matter.

The main indicator of the degree of heat is the magnet. After it ceases to react to the hot metal, it can be cooled. To do this, take the workpiece with tongs and dip in a bucket of water. If the hardening process is carried out correctly, the blade will leave scratches on the glass. However, a strong internal stress is formed in the metal, and when sharpened, it can begin to crumble. To avoid this, the blade must be released. This will relieve excessive internal stress. To this end, the blank is enough to put in the oven and hold it there for 2 hours at 200 ° C. Then you can turn off the oven and remove the blank after it has cooled.

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Final processing blade and handle nozzle

After all the thermal work is completed, you can start grinding the blade and stick the handle. To make the blade smooth, it is possible to process successively a metal brush, sandpaper and a felt circle. To make the knife inaccessible to rust, its blade is subjected to an etching process. It is dipped in ferric chloride, which is why it is covered with a gray protective film of a matte shade. If ferric chloride is not available, you can poison the blade with vinegar or grated raw potatoes. The resulting film reliably protects the steel surface from rust, so it is better not to scratch it.

Installation of the handle depends on its shape.

Deer horn is simply placed on the shank through a longitudinal hole pre-filled with epoxy resin. Stacked handle simply assembled and tightly clamped on the thread. The leather belt is tightly wound, smearing it in front of this special glue for the skin. The side panels of wood or bone are fastened with two rivets, often reinforcing them with epoxy resin. After fastening, they can be given a final look, undermined on a grinding machine, polished and rubbed with wax, dissolved in turpentine.

After making the knife was successful, it remains only to sharpen. This should be done manually, as a sharpening machine can overheat the blade and degrade its quality. You can use the usual abrasive bar. Such a knife will cut wood, leather, various types of plastics and even thin metal well. For editing, a round rod with a handle, called musat, which is often attached to sets of kitchen knives, is quite suitable.

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