Steel 9ХС and axes for various purposes

How to harden an ax: at home, video, hardening, blade, correctly

An ax is a universal tool that is used by every master due to his own experience, skills and dexterity.
At the same time, the main advantage is the ability to hold an edge and remain in working condition. Taking into account the specifics of using an ax, which consists mainly of chopping blows, only high-quality and hard metal that has undergone competent hardening is capable of maintaining the working part of the blade in a given state.

Unfortunately, many manufacturers save time and resources by shortening the production cycle and not completing all the necessary production steps in full, which deteriorates the quality of the finished tool.

This problem is solvable, but only for people who have the necessary knowledge in the field of metal processing. Let's consider the technology of hardening an ax at home.

What steel are axes made from?

For a knowledgeable person, the question of what steel an ax is made of is far from idle. The fact is that the quality of hardening directly depends on the brand, composition and other characteristics of the metal. Some types of steel simply cannot be hardened because they do not have the necessary components and cannot acquire the necessary properties during the preparation process.

Figure 1 – Types of steel

For the manufacture of construction axes, according to GOST 18578-89, the following grades of steel are used:

8ХФ, 9ХФ, 9ХС, ХВГ (according to GOST 4543);
60G (according to GOST 14959);
U7A, U8, U8A, U8GA, U9, U9A (according to GOST 1435).

It is necessary to take into account that a construction ax is a universal tool designed for constant and active use.

Unlike other types, this variety is used in a continuous mode, and therefore requires high-quality hardening of the blade, which prevents damage or rapid dulling of the cutting edge.

It is necessary to check what metal the ax is made of when purchasing it, however, it is impossible to determine whether hardening was carried out and how well this procedure was carried out.

Quality tools are sometimes marked with the grade of steel, but this information is of little use, especially for those who have never studied metallurgy.

The easiest way to determine the quality of steel is to take the tool by the handle, without touching the metal part, and sharply click on it with your finger or some hard object. If the sound is ringing and lingering, bell-type, the metal is good. A dull sound that immediately fades away indicates poor hardening or the use of unsuitable steel.

Another way to determine is to check for spark. If, when sharpening, long yellow stripes with luminous stars at the ends form on the emery, carbon steel was used, which can be properly hardened. If there are no stars, the steel is frankly weak and will not allow you to get the expected effect from hardening.

Important! The steel grade can be determined with high accuracy only in a special laboratory using a whole range of studies. At home, they only find out the metal’s ability to harden, which is usually quite enough.

How to properly harden a blade at home?

Hardening is a complex process, the result of which depends on the experience and knowledge of the master doing it. When hardening an ax, only the blade is subjected to the most severe treatment, and the butt and eye (hole for the ax) are left in their original state.

This is important, since hardening increases not only the hardness, but also the fragility of the metal, and continuous processing can make the tool unsuitable for work - any blow can split it.

Therefore, the hardening mode must be chosen so that the result is a hard strip of metal near the working edge and a softer, more viscous rest of the tool.

The essence of the process is the restructuring of the crystalline and atomic lattice of the metal, which occurs under the influence of high temperatures and a sharp change in the degree of heating. You will need a standard muffle furnace, which should be purchased or rented.

Main stages

The procedure consists of three main stages, which are performed sequentially without interruption:

Let's look at them in order.

Annealing

The annealing process is necessary to change the structure of the metal, cleanse the structural memory of the steel and relieve stress incurred during casting or previous processing.

Figure 2 – Heat treatment modes for steel U7, U7A

The procedure consists of performing two steps:

Heating to a temperature of 740-760°.
Smooth cooling up to 550° at a speed of 30-50° per hour.

Considering the temperature difference, we can conclude that the cooling process will take from 4 to 7 hours.

The main difficulty is temperature control.

Steel heated to 768° has a red-burgundy color with a dim glow.

Without experience, it is difficult to understand whether the metal has reached the desired temperature or not. An ordinary magnet will come to the rescue.

At a temperature of 768°, it ceases to be attracted to the surface of the steel, which makes it possible to determine the temperature with sufficient accuracy.

After reaching the desired degree of heating, the furnace is turned off, and the ax is left in it for gradual cooling. Usually the process lasts slightly longer than the calculated value - about 10 hours.

Hardening

To harden, the metal must be heated again to a temperature of 800-830°. First, the surface is cleaned of scale, for which you need to use a hard wire circle. Heating is carried out until the metal acquires a bright red tint.

Important! When heating to 800°, you will have to use your own understanding of the situation, since there are no more correct ways to determine the temperature at home. It is a good idea to look at a sample of the metal that has been heated for hardening beforehand to get an idea of what it should look like.

After heating, the metal must be cooled. Use water at a temperature of 30° and oil. The working part of the ax is immersed in water (3-4 cm), actively moving to prevent the formation of a vapor layer. The duration of immersion in water is 3-4 seconds, after which the entire ax is immersed in oil. At the same time, you need to make sure that it does not catch fire.

Vacation

Tempering is the final part of the entire process, designed to relieve metal stress and reduce its brittleness. Before starting the tempering, it is necessary to clean the surface of the ax again with a wire wheel, since it will be necessary to carry out visual inspection of the surface. It should acquire a blue tarnish color corresponding to the correct degree of heating.

The procedure is carried out in a conventional oven heated to 300°. The ax is placed in the oven and kept for 1 hour, after which it is removed and cooled naturally in the open air. Test processing with a file can be a criterion for the quality of hardening.

Attention! The higher the tempering temperature, the softer the metal will become.

Self-vacation

Self-tempering is a process that combines the hardening and tempering operations into a single procedure.

Its essence lies in the sharp cooling of the working part of the tool without additional cooling of the entire ax.

Figure 3 – How the color of steel changes when the ax is heated

A situation arises when the cooled part is heated to the required temperature due to thermal energy from the remaining part that has not been cooled.

The process is controlled by the color of the tarnish.

When the instrument acquires the desired color, it is finally cooled in water or oil.

Self-release is a rather complex procedure, the result of which depends on the experience and skills of the master. It saves time significantly, but it is better for an untrained person to complete the entire process so that they do not have to perform the entire hardening operation again.

The length of time the ax is kept in the oven, the time required for reheating and other nuances of the process depend on a lot of factors, including the size and shape of the ax, so it is unlikely that you will be able to get the expected result the first time. For the first time, it is recommended to involve an experienced thermist in the work and get a lot of useful information from him.

Rule 3: consider the weight of the tool

Not only the ease of use and carrying will depend on how much the ax weighs. Undoubtedly, it is easier to swing with a light hatchet, and your hands will get less tired during prolonged work. But it is not a fact that with the help of such a tool you can cope with a large log. The weight of the ax primarily affects the strength of its impact on the material, that is, the heavier it is, the stronger the blow. For example, you need to cut a thick log. A hatchet weighing 0.5 kg is, of course, easier to swing, but you will have to make many blows before the log splits. By taking a heavier tool, weighing more than 1 kg, you can cope with this task in just a couple of blows. Lightweight models are more suitable for carpentry work, cutting off branches, making grooves, and they are also taken on hikes to chop wood for making a fire.

Ax – 115 photos of the best tools and making it yourself

A universal tool that may be needed at the dacha, on a hike in the forest, or just on vacation near a river, or at home for household purposes, is an ax. Despite its simple design, this device has many uses and varies in manufacturing methods and quality.

Main characteristics

All types of axes are divided into three main groups:

splitting axes;
for felling work in the forest;
universal tools for construction and household purposes.

Within each identified group, there are varieties that are determined by the purpose and characteristics of the component parts. Taking into account the most important parameters will help you decide which ax is best to choose. It is worth noting the fact that you simply cannot do without an ax on a summer cottage!

Weight parameters

The possibility of its use in wood processing depends on how heavy the tool is. The minimum value is considered to be a mass of 0.9 kg. Lighter models are used only for a limited range of household and household purposes when finishing small workpieces, for example, for sharpening wedges.

For standard work with wood, you will need a tool of 0.9-1.7 kg. It will be effective both when cutting medium-thick firewood and when carrying out construction work. Heavier splitting axes weighing 2.2-2.5 kg are used for chopping large firewood. They have a longer ax handle.

Blade shape and sharpening

In practice, axes with three types of butts are used:

wide, designed for felling timber;
average, having a universal purpose;
narrow - used when carrying out neat carpentry work.

Features of the shape of the blade can be assessed from the photo of the axe. Straight sharpening allows you to deliver high-quality chopping blows, but curved sharpening is suitable for both chopping and piercing movements. For example, a small, rounded blade is designed to penetrate deeper into the wood and cut fibers in the transverse direction.

With a sharpening angle of up to 40 degrees, increased penetration into the workpiece is ensured, although the dulling speed will be higher. In cleavers, the degree of sharpening at different edges of the blade will vary.

Blade material

For carpenter's axes, the blade is made by stamping low-carbon steel. Greater strength of the tool for lumberjacks is provided by forging steel U7 and 60G.

It should be remembered that the use of mild steel causes the tool to quickly become dull. Blades made of hard or hardened steel are prone to chipping.

Making an ax

The length of the ax depends on the purpose of the tool. The most comfortable indicator is 50-70 cm. But we must remember that the swing and force of the blow depend on the length. Therefore, for heavier work, a tool larger than 70 cm is required.

The ax handle can be metal, including one with a special rubber lining. This is a more durable design, but it has a big drawback - it does not dampen vibration well.

The force of the blow, together with the resistance of the workpiece, is absorbed by the axe. And therefore it is recommended to use wood, in particular birch, for its manufacture. But cheaper and more accessible pine dampens vibration much worse.

A tool with an oak handle is suitable for lumberjacks. The handle itself should be comfortable, without knots or chips. At the end of the ax there is a thickening and a hole for fastening.

Types of axes

Depending on the purpose and intended use, you can choose the optimal design of the tool. There are various types of axes on sale.

Tourist

This is a lighter and more compact tool that can have a rounded blade shape. It is sharp and can be used as a knife. Handle length up to 50 cm. Supplied with a protective cover.

Such an ax is quite expensive, cannot be used for chopping, and rust often appears. Popular brands include Geter Gator II and Expedition HB-040.

Household and catering

In everyday life or in food establishments, axes are used for chopping meat or bones. The design features a wide blade made of durable steel with an angled sharpening. This is a heavy and durable model.

The big disadvantage is the need to use physical force to work. Also, the wooden ax handle can dry out. The products “Meat Chopper” and “Trud” VACHA S901 are known.

For firewood

The catalog of axes in this category with the best quality includes products from TUTAHI, KRAFTOOL Rhine and Universal.

For these purposes, models with a hardened steel blade with a sharpening of 40-60 degrees and a wooden ax are used. This ensures simplicity and efficiency in operation.

Bilateral

This tool has two identical high-carbon steel blades that provide excellent balancing. The sharpening angle can be different, and the ax handle can be replaceable.

However, this is a traumatic and heavy design, which excludes the possibility of use as an impact tool. Experts recommend models such as SOG F12 and OCHSENKOPF.

For wood cutting

A large ax with a long handle for a strong blow. There is a rounded blade. The instrument has a narrow specialization and is used only for its intended purpose. Lumberjacks may find HULKAFORS, SCANDINAVIAN FOREST AX or WETTERLINGS AMERICAN FOREST AX brands suitable.

Plotnitsky

This is a well-balanced tool with a sharp blade and a comfortable handle. You cannot use it for chopping, and after purchasing the product you need to select the required sharpening characteristics.

You can choose Gardena 1000A 08714-48.000.00 or Wetterlings Hjartum Carpenter's Ax for this purpose. The Izhevsky ax is also popular.

Forged

The highest quality, strongest and most durable products. A forged ax is most often made to order. The Taiga brands and products from the Phoenix workshop are popular.

Cleaver

This ax has an elongated handle, a steel blade with a sharpening of 40-60 degrees. This is a highly specialized instrument that is well balanced. Used for processing thick and dense wood. Experts recommend using VIPUKIRVES or Council Tool Hudson Bay Ax products.

Dachny

Axes “DACHANT” standart SZAN330, T-03-1 or VOREL 33107 will help solve everyday problems on a country plot. Such models are suitable for chopping firewood and are used when cutting logs.

They are distinguished by their versatility, a blade made of durable steel and a wooden handle, which, however, can dry out after 5 years.

Making an ax with your own hands

If you are interested in the question of how to make an ax, then remember that you will not be able to make a blade from scratch yourself. You can only give a regular blade the desired shape by processing it with a grinder or an emery wheel.

But it’s quite possible to make an ax handle.

To do this you need:

select a workpiece with a diameter of more than 120 mm and a length 200 mm longer than the planned handle;
dry for several months at a temperature of 22-24 degrees and a humidity of 15%;
using an ax or large knife, remove excess wood in accordance with the outlined contour;
carry out processing with a chisel and hammer.

Now it is important to learn how to mount an ax correctly. This is done using gauze and epoxy resin. The presence of a wedge provides better strength. After this, grinding is done, and the ax handle is varnished. Sharpening is done on a machine or manually.

An ax is a useful assistant both in the country and on a hike and when working in the forest. You just need to choose the right model, focusing on the required characteristics and workmanship of a particular instance.

Photo of an ax

Rule 1: carefully inspect the working part

Since the main purpose of the ax is chopping, first of all, when purchasing, you need to pay attention to its working part. It is made of steel: tool, carbon or alloy. The latter are considered the most durable. The working part consists of a butt, which is attached to the handle, and a blade with a blade at the end. The shape of the blade determines what kind of work the ax is intended for. For example, the extended working part is suitable for cutting trees or large logs. The human force upon impact is evenly distributed across the entire width of the blade, which allows you to immediately capture a large area of material. This form of blades is usually found in so-called felling or construction axes. Hiking, gardening and carpentry axes have medium-width blades . This allows you to carefully cut off branches, trim logs, cut grooves, etc. There are also tools with a narrow working part , which is convenient for chopping firewood, sharpening wedges, and preparing wood chips, which is why they are also called splitting axes.

The edge of an ax blade can be straight or rounded. The latter will be very convenient if you need not only to prick, but also to cut, which will be useful when performing carpentry work. It is also important to consider the sharpening of the ax. A very sharp blade penetrates the material better, but is more fragile. Therefore, for cutting large logs, axes with a blade sharpened at an angle of 30-40 degrees are intended. The most optimal sharpening is considered to be the so-called Finnish blades, the edge of which is sharpened at an acute angle from below, and at a more obtuse angle from above.

Expert advice: if you bought an ax and decided to check its quality again, tap the blade. If a ringing sound is heard, then the material is durable, and the instrument will cope well even with hard wood and will last a long time.

Hardening an ax at home - video, photos, nuances

How to qualitatively harden an ax at home? The relevance of this issue is explained by the wide demand for this tool. In addition, using the example of such a simple household tool as an ax, one can examine in detail the nuances of several types of heat treatment - annealing, hardening and tempering.

A good forged ax can cut a nail

It is quite easy to find out that a new ax purchased from hand or at a hardware store needs to be hardened: if the blade of the tool is very soft (which can be determined by its wrinkles even when cutting knots of small thickness), then it needs high-quality hardening. If cracks appear on the working part of the ax during operation or the blade becomes chipped, it should be fully tempered.

What steel are axes made from?

To determine how well the ax has been hardened, you can use a regular file that is not very worn and has a fine notch.

If the hardness of the working part of the ax is high, the file will easily slide along it; if it is medium, then the tool will slightly remove roughness; if it is low, the file will take the metal well.

If the ax is hardened in accordance with generally accepted requirements, then the sharpest part is the hardest (about 3 cm wide from the blade), and the metal in the rest of the tool is softer.

Purpose of tool carbon steels

As a rule, axes are made from steel of these grades

Once you have determined that the tool still needs to be hardened, you need to determine what metal it is made of.

Enterprises operating in full compliance with approved regulatory documents (GOSTs) produce axes from certain steels, the grades of which are specified in a special table.

Naturally, each of these alloys requires its own heating temperature and a certain cooling medium, which will ensure the required quality of heat treatment. All similar parameters for each steel grade can also be found in special reference books.

Annealing modes of carbon steels

Heat treatment modes using the example of steel grades U7 and U7A

Of all the types of steel used for the manufacture of axes, the most common are tool steel alloys of grades U7 and U7A. That is why, as an example, we will look at how to harden the working part of an ax made from U7 alloy.

The main stages of hardening an ax

If you need to harden an ax at home, you need to dull its cutting edge, bringing its thickness to 1 mm. The procedure for heat treatment of a tool, which can also be done at home, consists of several stages.

Rule 2: pay attention to the ax handle

First you need to decide which material will be preferable. Traditionally, the tool's ax was made of wood , and today this material is the most popular. Most often, birch, oak, ash and other dense woods are used, which produce an elastic handle that can absorb shock. When choosing an ax with a wooden hatchet, you need to pay attention to the direction of the fibers - they should run along. There should be no defects in the array, for example, traces of knots or cracks. This is a guarantee that the handle will withstand strong impacts and will not crack. The only drawback of such axes is that the handle may darken from dampness or dry out over time. Therefore, if you choose an ax to work in such conditions, it is better to give preference to a model with a handle treated with paint or varnish.

Also on the hand tool market are metal . As a rule, the ax handle with the blade has an all-metal construction, so these products are very reliable. For a comfortable grip, the handle is equipped with a rubberized pad that prevents your hand from slipping during operation. But such instruments are slightly heavier than those with a wooden handle.

Recently, axes with fiberglass (or, as it is also called, fiberglass) have appeared in the assortment of many European manufacturers. This material is produced on the basis of polyester resins; when hardened, it has the strength of metal, is not subject to rotting and corrosion, and does not deform from mechanical stress and exposure to aggressive environments. As for practical benefits, the use of fiberglass for the manufacture of impact instruments significantly improves the performance of products. In the event of a strong impact, such an ax will not only withstand a large mechanical load, but will also reduce the impact of vibration on the user’s hands. To prevent your hand from slipping, the handle may have a solid rubber pad or several corrugated rubber inserts.

When choosing an ax, also pay attention to the length of the handle . For tourist hatchets it is short – about 20 cm, which makes the tool lighter and more compact. It does not take up much space in your backpack, and can also be hung on your belt. For devices for chopping trees or splitting firewood, the length of the ax is from 35 to 50 cm. This ensures a good swing and allows you to strike with great force.

Expert advice: the optimal length of the ax is one that is 6-7 times the width of the butt. This ratio ensures that the swing is comfortable and that the design of the instrument can withstand heavy impacts.

In addition to strength and reliability, the ax handle should also be comfortable. It depends on its shape. Most tools have a curved handle to provide a secure grip. Make sure that the handle is not too curved, otherwise this area will be most vulnerable to impact and the ax handle may crack. The end of the handle is usually slightly widened so that the tool does not fall out of the hand if it accidentally slips. An additional guarantee that the ax will not fall out will be provided by the presence of a hole in the handle for threading a lace. By securing your wrist in the loop, you will be more confident that the risk of injury is minimal while working.

The best steel for an ax

In modern times, advanced and modern technologies make our lives easier, thereby displacing all the old and reliable technologies. At the moment, almost all equipment runs on gasoline or electricity. But the technology has not yet touched the ordinary ax.

Today, almost every resident of a private or country house has an ax. This tool is an indispensable assistant in the home, on the farm and in other works. However, it is advisable that there should be not one ax in the house, but several, since axes have different purposes.

So, for example, carpenter's axes are intended for small carpentry and carpentry work, forged axes are most often used for chopping firewood, and there are axes for chopping meat.

Currently, there is a huge selection of types of axes, and therefore choosing the necessary ax model for yourself is very difficult. All of them have their own technical features, properties and characteristics, and have different prices. However, many people choose high-quality axes for themselves, but choosing such an ax is very difficult.

Choosing steel for an ax

The service life of an ax largely depends on the steel from which the blade is made. As a rule, manufacturers use steel with a high percentage of carbon to make an ax; such steel has very high resistance to temperature changes, as well as to external influences.

Therefore, for many buyers the question becomes which steel to choose? This is an important factor, if not a determining one, so you need to approach it carefully and thoughtfully.

Currently, the marking of steel axes also has a letter designation from the times of the USSR. (U7A; U8; U8A; U8GA) all of the listed steel grades are the most suitable for an axe, so it is recommended to choose an ax with this marking.

In order to ensure the quality of the steel before purchasing the ax you need, you need to strike the ax blade with some hard object. After which, there should be a loud and prolonged sound, if this does not happen, then refuse to purchase this ax.

Best carpenter's ax

Carpenter's axes have a very convenient and comfortable handle, while the thickness of the blade is medium in size. However, many skilled carpenters sharpen the blade only at their own discretion.

In this case, the weight of the ax is of no small importance; this should also be taken into account, since carpentry work has its own specifics and features. Therefore, carpenter's axes are an indispensable assistant when performing various carpentry works.

However, an ax in this category has its certain pros and cons:

Pros:

has a high degree of balance.
has a comfortable handle shape.
You are allowed to sharpen the blade yourself at your own discretion.
has a special coating on the blade that prevents friction with wood.

There is one minus - it is not suitable for chopping wood.

Best forged ax

This ax model is made using forging, and such work is usually performed manually by a qualified craftsman. To make a forged ax, only very high quality steel is used, since this determines how high quality the product will be.

Forged axes have one distinctive feature from axes of other models: the use of the ax head as a hammer or sledgehammer, which makes such a tool universal.

However, an ax in this category has its pros and cons:

Pros:

Such products are made individually.
They have a comfortable and long handle.
made of high quality materials, its blade is made of hardened steel; it is universal; with such an ax you can chop wood, fell wood, or cut up a carcass.
has a long service life.
does not have significant weight.

Disadvantage: since this is handmade, the cost of such a product will be very high.

Therefore, if you have any questions or doubts about choosing an ax, you can look at the photo of a good ax.

Of course, we can say that there is nothing complicated or incomprehensible in choosing an ax. However, this is absolutely not true. The fact is that when choosing an ax, you need to decide why you need an ax in general, and for what purposes?

Next you need to pay attention to the grade of steel and sharpening of the blade. After that, you can choose the handle for yourself. Which should be comfortable and could be held comfortably and pleasantly.

Photo tips for choosing an ax

Content:

The ax is one of the oldest hand tools, which since ancient times was considered in Rus' an indispensable assistant in any family.
You need to build a hut, chop wood - you can’t do without an ax! Every man was engaged in carpentry from a young age, and a good ax was his pride. It was indecent to ask someone for an ax; everyone had to have their own tool. The worker got used to it; the handle seemed to be an extension of his hand. It was believed that one family should have several axes of different shapes for different jobs. No wonder the Russian proverb says: “In seven yards there is one ax - from poverty.” Some men sharpened their ax so diligently that you could actually shave with the blade - that’s the only joke today. The ax has been sung more than once in Russian folklore. And how many architectural monuments were erected with its help! Ensembles of wooden architecture have survived to this day in Kizhi, Kostroma, Suzdal and other cities. Today, the ax is used for the same purposes as before - collecting firewood, carpentry, cutting down trees, construction. And its appearance is not much different from the original: a long handle with a working part attached to it, which has a sharp blade. Despite the fact that its design is quite simple, the modern ax has undergone some changes. Various manufacturers are trying to improve this tool to make it even more effective and convenient to use. There are little things that are not immediately noticeable, but play an important role when used. So, so that you don’t miss anything, we’ll tell you in order how to choose the ax that best suits you.

Hardening and heat treatment of an ax

Blacksmith Valery Samovich: “Using an ax as an example, I want to talk about the heat treatment of steel at home, which includes three stages: annealing, hardening and tempering. The need for hardening arises if the manufacturer violates the heat treatment technology.

If the ax quickly becomes dull during use and dents appear on the tip, then the steel is soft. And this means that the ax is not hardened. And if the tip chips or cracks, that is, the steel is very hard and brittle, then this is possible if tempering has not been carried out after hardening.” A clean file with a fine notch will help us evaluate the hardness of steel, and therefore the quality of hardening.

If the hardness of the steel is high, then the file glides over it almost without catching. If the hardness of the steel is average, then the file will take it a little. And if the hardness of the steel is low and the file takes it easily, it means that the steel is not hardened, or the heat treatment technology was violated.

In the case of this axe, the file takes it easily. In this case, as well as in the case of increased fragility, the ax is subjected to a full heat treatment cycle. First, annealing, and then quenching and tempering. Correct hardening of an ax is considered to be hardening in which different parts of the ax are hardened differently.

In the area of the blade, at a distance of about three centimeters from the tip, the hardness of the steel should be high. The hardness of the rest of the ax should be much less. This hardening ensures the wear resistance of the blade and the ductility of the rest.

And it is a guarantee that during operation the butt will not burst or the blade will not break off.

GOST 18578 – 89 construction axes

The next point that we need to know to carry out effective heat treatment is the grade of steel from which the ax is made.

All construction axes that were manufactured in the Soviet Union and are now manufactured in the post-Soviet space must comply with GOST 18578 - 89 Construction axes.

This GOST specifies steel grades for the manufacture of axes. Each of these steels has its own heat treatment temperature regimes. And your own quenching media.

You can find out about this in steel grade books or in thermist’s reference books, which are freely available in the library. However, I want to emphasize the fact that the main materials for making axes are U7 and U7A steels. The ax I chose for experiments has a mark.

Above, the year of manufacture is 1963. On the left is the size according to GOST A2. On the right is steel. From which the ax is made. This is tool, carbon steel U7. Heat treatment modes for U7 steel are as follows:

Before heat treatment, the cutting edge of the ax must be dulled so that its thickness becomes approximately one millimeter.

Vacation

The last heat treatment operation is called tempering. Tempering is necessary to reduce the brittleness of hardened steel and relieve internal stresses in the metal that appeared during the hardening process. I bake in a regular oven.

The ax is kept for one hour at a temperature of 300 degrees, and then cools in air. This is the handsome guy we got after our vacation. The color of the tarnish is blue, indicating that the tempering temperature was approximately 300 degrees.

You can see this color if you turn the metal surface towards the light in a certain way. We check the hardness of the metal after tempering and make sure that the blade has become a little softer. As we already know, the hardening temperature of U7 steel is 800-830 degrees. And it cannot be reduced.

At lower temperatures, hardening may not occur at all. But what should we do if, after hardening, we need to obtain ductile steel with a relatively low hardness? In this situation, we harden the steel as expected, but increase the tempering temperature.

The higher the tempering temperature, the more ductile and softer the steel will be after tempering. Data on the hardness of steels after tempering, depending on the tempering temperature, is available for each grade in steel grade books.

Hardening with self-tempering

Another method of hardening a tool is self-tempering. First, the tool is heated in a furnace to the hardening temperature. Then, the cutting part is cooled to a temperature of 150-170 degrees. After this, the cutting part is cleaned of scale in order to see the tarnish colors. Let's see how the purple color goes.

The tool is kept in air until the heat from the hot part heats the cooled part to a temperature of 250-300 degrees. We judge this by the color of the tarnish. Everything is purple. Cool. Water is used as a quenching medium. Only to cool the cutting part it is heated to 30 degrees.

And for the final cooling of the ax it is heated to 50 degrees.

Annealing

So, let's start heat treatment. The first operation is called annealing. Before hardening an ax or any other tool, it is necessary to anneal it. Annealing is a kind of zeroing of the structural memory of the metal. It consists of heating the entire instrument to a temperature of 740-760 degrees and gradually cooling it to 550 degrees. At a speed of approximately 30-50 degrees per hour. Annealing is best done in a brick kiln. The most important question is how to determine the temperature of the metal. A professional can easily determine the temperature by color. Well, a regular magnet will come to the aid of a beginner.

The fact is that steel, like iron, stops being magnetic at a temperature of 768 degrees . As the magnet heats up, we check whether the steel is magnetic. When the magnet stops sticking to the steel, this means that the temperature of our ax has exceeded 768 degrees and there is no need to heat it any more. We remember the color of the glow for a temperature of 768 degrees. It's called red-burgundy. We will need this knowledge when hardening, which is carried out at a temperature of 800-830 degrees, which corresponds to the transition from dark red to red. On the screen you see a table of heat and tarnish colors for carbon steel.

I would like to draw your attention to the fact that the camera distorts the real color, making it lighter. So, the temperature required for annealing has been reached. We move the coals away from the axe, close the stove, close the main valve and leave for 10 hours. Let the ax cool down along with the stove. During the annealing process, the microstructure of the metal is improved, internal stress is relieved and hardness is reduced. After cooling, the annealed steel becomes soft and can be easily taken with a file.

Rule 5: do not forget about the manufacturer

Perhaps someone will think that buying a branded hand tool is a waste of money. But “nameless” axes, which can be found on the market or in a hardware store at a very low price, are not reliable. Almost every second such tool eventually becomes loose in the part where the ax is connected to the butt. When swinging or when the blade enters wood, the blade may fly off and cause injury to the user or bystanders. In addition, such axes are not always sharpened well, so they become dull even with short-term use.

If we talk about branded ones, then such tools are more reliable and durable. Manufacturers care about the quality of steel , improve forging technology , and also develop new ways of attaching the working part to the handle . For example, BAHCO axes have a special wedge that provides additional fixation at the junction of the striker and the axe. Finnish Fiskars axes undergo double hardening of the blades and application of an anti-friction coating, which provides increased strength and wear resistance. In addition, when purchasing a branded ax, you receive a guarantee for its use. For different manufacturers, its period is 1-2 years, and for some it reaches 3 years.

Rule 4: check the availability of additional accessories

When choosing an axe, make sure that there is a rubber or plastic protective pad on the blade. It not only covers the sharp edge, making the tool safe to carry and store, but also prevents the blade from becoming dull or rusty. Also, many manufacturers include a cover with the ax, most often a canvas one. It performs the same functions as the protective pad, only it covers not only the blade, but the entire working part. Some cases have a loop through which the tool can be hung on a belt - this is very convenient on a hike, when the ax needs to be at hand, and at the same time it will not get in the way.

Choosing the right one

First of all, when visiting a store, you need to pay attention to the brand of the instrument - Finnish and German products are usually distinguished by a high level of performance, and Chinese brands, as a rule, can only boast of a low price, often at the expense of durability and quality. However, it is unlikely that it will be possible to determine the properties of this or that ax only by the country of origin, so when choosing a weapon that is optimal for all characteristics, you should focus on the following characteristics:

quality of the blade - with a light click of a finger, good steel will ring melodiously, while a lower quality product will have a dull sound that quickly fades away;
ax weight – for a wide range of household tasks, a tool no heavier than 1-1.2 kg is sufficient, since a more massive one requires significant physical effort during prolonged work, and lightweight options are mainly suitable for fine work with wood;
handle material - regardless of what the ax handle is made of, the grip area should be non-slip and provide reliable grip between the hand and the tool.

When choosing, it is also necessary to take into account the suitability of the ax for the height and physical capabilities of the user. Thus, you can determine the optimal length of a weapon if you take it by the ax at the bottom of the butt in the direction of the shoulder - a handle that is too long will rest against the shoulder.

The appropriate weight is determined as follows: the ax is taken by the end of the handle so that the hand with the tool hangs freely under the influence of gravity. Then you need to try to lift it, leaning on the hand of your free hand, pressed above the elbow joint - if it was not possible to bring the instrument into a vertical position, then it will not be so easy to work with it.

Choosing the right one

quality of the blade - with a light click of a finger, good steel will ring melodiously, while a lower quality product will have a dull sound that quickly fades away;
ax weight – for a wide range of household tasks, a tool no heavier than 1-1.2 kg is sufficient, since a more massive one requires significant physical effort during prolonged work, and lightweight options are mainly suitable for fine work with wood;
handle material - regardless of what the ax handle is made of, the grip area should be non-slip and provide reliable grip between the hand and the tool.

The appropriate weight is determined as follows: the ax is taken by the end of the handle so that the hand with the tool hangs freely under the influence of gravity. Then you need to try to lift it, leaning on the hand of your free hand, pressed above the elbow joint - if it was not possible to bring the instrument into a vertical position, then it will not be so easy to work with it.

Rules of care

The metal surface after heat treatment is black. A layer of oxides is formed, which protects the tool from corrosion. You cannot remove blackening with grinding wheels “for beauty”. Only the working edge of the blade should shine after sharpening.
Before long-term storage, the head is lubricated with oil. Experienced carpenters do not recommend using machine lubricants for this purpose. They use castor, linseed or vaseline oil. After lubrication, wipe the head - a thin film is enough to protect against rust.
The tool should not lie on the ground, on a concrete floor or stand near a wall for a long time. The geometry of the ax is disrupted. That's why they hang him up. The wooden part is impregnated with oil so that the wood does not dry out.

How to sharpen an ax correctly

In production, cutting edge geometry is developed using a grinder. This is a belt sander. On an abrasive of this shape, a convex cutting edge is more easily formed.

While working with an axe, it is enough to regularly adjust the cutting edge with a fine abrasive stone. The angle specified during sharpening in production is not violated.
For universal axes, the sharpening angle is 20-30 degrees, for carpentry tools - 35 degrees. The steel is hard enough to hold an edge for a long time.
If you need to restore the cutting edge and eliminate chips, use an electric sharpener. A grinder is not suitable for this purpose.
It is very important to maintain the sharpening angle. They operate at low speeds to avoid beating of the blade and strong heating of the metal. As the temperature rises, the structure of the hardened steel changes and the blade loses its hardness.
To cool, add water or take breaks from work.