In engineering wrench called a specialized tool that is designed to assemble or disassemble threaded connections. To do this, they unscrew bolts or nuts from other parts, or screw them to them.

All spanners in technology are divided into two main varieties: covered and covering. Holes into which nuts or bolt heads are inserted are called gaps, and their dimensions are standardized. In the metric system they are measured in millimeters, and in the inch system they are measured in fractions of an inch.

Despite the fact that the design of the wrench is very simple and unpretentious, it finds extremely wide application: almost no assembly production can do without this tool, it is necessary when repairing a wide variety of equipment. There are wrenches in space too, such as on the International Space Station.

If we talk about which of the many varieties wrenches more common than others, then these are, of course, carob. As for the material used for their manufacture, the most common is high-quality tool steel, in which chromium and vanadium are present as the main alloying additives.

GOST 6424 - 73

Keyholes and key sizes
Dimensions S; S1; S2; S3	Limit deviations key sizes			Limit deviations of turnkey dimensions
	S		S1	S2			S3
	Keys of normal precision	Coarse Precision Keys		Products increased accuracy	Products of normal accuracy	Coarse precision products
2.5*	-	-	−0.040	-	-	-	+0.09 +0.03
3.0*	-	-	−0.040	-	-	-	+0.09 +0.03
3.2	+0.08 +0.02	-	−0.048	−0.16	-	-	+0.12 +0.04
4.0	+0.12 +0.02	-	−0.048	−0.16	-	-	+0.12 +0.04
5.0	+0.12 +0.02	-	−0.048	−0.16	-	-	+0.12 +0.04
5.5	+0.12 +0.02	-	−0.048	−0.16	-	-	+0.12 +0.04
6.0*	+0.15 +0.03	-	−0.048	−0.16	-	-	+0.12 +0.04
7.0	+0.15 +0.03	-	−0.058	−0.20	-	-	+0.15 +0.05
8.0	+0.15 +0.03	+0.18 +0.03	−0.058	−0.20	−0.36	-	+0.15 +0.05
(9.0)	+0.15 +0.03	+0.18 +0.03	−0.058	−0.20	−0.36	-	+0.15 +0.05
10.0	+0.19 +0.04	+0.24 +0.04	−0.058	−0.20	−0.36	-	+0.15 +0.05
(11.0)	+0.19 +0.04	+0.24 +0.04	−0.120	−0.24	−0.43	-	+0.18 +0.06
12.0	+0.24 +0.04	+0.30 +0.04	−0.120	−0.24	−0.43	-	+0.18 +0.06
13.0	+0.24 +0.04	+0.30 +0.04	−0.120	−0.24	−0.43	-	+0.18 +0.06
14.0	+0.27 +0.05	+0.35 +0.05	−0.120	−0.24	−0.43	-	+0.18 +0.06
(15.0)	+0.27 +0.05	+0.35 +0.05	−0.120	−0.24	−0.43	-	+0.18 +0.06
16.0	+0.27 +0.05	+0.35 +0.05	−0.120	−0.24	−0.43	-	+0.18 +0.06
17.0	+0.30 +0.05	+0.40 +0.05	−0.120	−0.24	−0.43	-	+0.18 +0.06
18.0	+0.30 +0.05	+0.40 +0.05	−0.120	−0.24	−0.43	-	+0.18 +0.06
19.0	+0.36 +0.06	+0.46 +0.06	−0.140	−0.28	−0.52	-	+0.21 +0.07
21.0	+0.36 +0.06	+0.46 +0.06	−0.140	−0.28	−0.52	-	+0.21 +0.07
22.0	+0.36 +0.06	+0.46 +0.06	−0.140	−0.28	−0.52	-	+0.21 +0.07
24.0	+0.36 +0.06	+0.46 +0.06	−0.140	−0.28	−0.52	-	+0.21 +0.07
27.0	+0.48 +0.08	+0.58 +0.08	−0.140	−0.28	−0.52	−0.84	+0.21 +0.07
30.0	+0.48 +0.08	+0.58 +0.08	−0.140	−0.28	−0.52	−0.84	+0.21 +0.07
32.0	+0.48 +0.08	+0.58 +0.08	−0.170	−0.34	−1.00	−1.00	+0.25 +0.05
34.0	+0.60 +0.10	+0.70 +0.10	−0.170	−0.34	−1.00	−1.00	+0.25 +0.05
36.0	+0.60 +0.10	+0.70 +0.10	−0.170	−0.34	−1.00	−1.00	+0.25 +0.05
41.0	+0.60 +0.10	+0.70 +0.10	−0.170	−0.34	−1.00	−1.00	+0.25 +0.05
46.0	+0.60 +0.10	+0.70 +0.10	−0.170	−0.34	−1.00	−1.00	+0.25 +0.05
50.0	+0.60 +0.10	+0.70 +0.10	−0.170	−0.34	−1.00	−1.00	+0.25 +0.05
55.0	+0.72 +0.12	+0.92 +0.12	−0.200	−0.40	−1.20	−1.20	+0.30 +0.10
60.0	+0.72 +0.12	+0.92 +0.12	−0.200	−0.40	−1.20	−1.20	+0.30 +0.10
65.0	+0.72 +0.12	+0.92 +0.12	−0.200	−0.40	−1.20	−1.20	+0.30 +0.10
70.0	+0.72 +0.12	+0.92 +0.12	−0.200	−0.40	−1.20	−1.20	+0.30 +0.10
75.0	+0.85 +0.15	+1.15 +0.15	−0.200	−0.40	−1.20	−1.20	+0.30 +0.10
80.0	+0.85 +0.15	+1.15 +0.15	−0.200	−0.40	−1.20	−1.20	+0.30 +0.10
85.0	+0.85 +0.15	+1.15 +0.15	-	−0.87	−1.40	−1.40	-
90.0	+0.85 +0.15	+1.15 +0.15	-	−0.87	−1.40	−1.40	-
95.0	+0.85 +0.15	+1.15 +0.15	-	−0.87	−1.40	−1.40	-
100.0	+0.85 +0.15	+1.15 +0.15	-	−0.87	−1.40	−1.40	-
105.0	+1.00 +0.20	+1.40 +0.20	-	−0.87	−1.40	−1.40	-
110.0	+1.00 +0.20	+1.40 +0.20	-	−0.87	−1.40	−1.40	-
115.0	+1.00 +0.20	+1.40 +0.20	-	−0.87	−1.40	−1.40	-
120.0	+1.00 +0.20	+1.40 +0.20	-	−0.87	−1.40	−1.40	-
130.0	+1.25 +0.25	+1.40 +0.20	-	−0.87	−1.40	−1.40	-
135.0	+1.00 +0.20	+1.40 +0.20	-	−1.00	−1.60	−1.60	-
145.0	+1.25 +0.25	+1.40 +0.20	-	−1.00	−1.60	−1.60	-
150.0	+1.25 +0.25	+1.40 +0.20	-	−1.00	−1.60	−1.60	-
155.0	+1.25 +0.25	-	-	−1.00	−1.60	−1.60	-
165.0	+1.25 +0.25	-	-	−1.00	−1.60	−1.60	-
170.0	+1.25 +0.25	-	-	−1.00	−1.60	−1.60	-
175.0	+1.25 +0.25	-	-	−1.00	−1.60	−1.60	-
180.0	+1.25 +0.25	-	-	−1.00	−1.60	−1.60	-
185.0	+1.25 +0.25	-	-	−1.15	−1.90	−1.90	-
200.0	+1.25 +0.25	-	-	−1.15	−1.90	−1.90	-
210.0	+1.25 +0.25	-	-	−1.15	−1.90	−1.90	-
225.0	+1.50 +0.30	-	-	−1.15	−1.90	−1.90	-

Key hole making

In most cases response elements on a turnkey basis have hexagonal or square holes dimensions which are specified by the standard. Unlike round holes, technological process their manufacture is much more complex and highly labor-intensive. These holes are most often the result of processes such as milling and broaching. In addition, equipment such as slotting machines is used to obtain them, specialized firmware is used. Recently, advanced methods such as electrical discharge machining and laser cutting have been used, among other things.

To obtain square hole, you can use such a non-standard method as drilling using a specialized tool. This method is based on the trajectory cutting tool called the Reuleaux triangle. So it is named after its inventor, the French mechanical engineer Franz Relo, who at the turn of the 19th and 20th centuries taught at the Berlin Royal Academy of Technology, and eventually became its president. The essence of the "Reuleaux triangle" is that the cutting tool does not move in straight lines, but in arcs that have the same radius and size. If this movement of the drill is used during the drilling process, then a square hole can be obtained, in which the corners are very slightly rounded.

drilling

In engineering, drilling refers to a technological process for which either spiral or other types of drills are used. The result of using this cutting tool is the formation of holes in parts, blanks or semi-finished products that have a given diameter and a strictly defined depth.

In cases where they are made key holes, drilling is used as an auxiliary technological operation. It is necessary in order to pre-treat the hole.

Erosion processing

EDM is a directed impact on the material of pulsed discharges, resulting in the destruction of a certain layer of the material being processed. It is placed under a special electrode.

With the help of electroerosive technology, it is possible to process materials of almost any degree of hardness, and to make holes in them of any configuration, including key holes.

Stretching

This technological process is one of the varieties of metal cutting. It is used to carry out operations on both external and internal surfaces, it is applied to both metallic and non-metallic materials. Stretching can be used to make key holes of the highest quality.

laser cutting

This method is by far considered the most advanced and most effective in all respects. In the process of processing a metal with a laser beam, a part of it evaporates, and as a result, either blanks or finished parts are obtained.

All about wrenches - types and classification

Wrench - it would seem that such a simple tool, which can not be said much. However, as it turned out, a lot can be said about this surprisingly simple tool. In this article we will try to tell everything related to wrenches - their types, purpose, what keys are made of, and so on, where they can somehow appear.

The main types of wrenches

So, let's start with the most important thing - the types of wrenches that exist today. So, until recently, there were only 3-4 types of keys, but by today, their number has slightly increased due to a slight “modernization”. Well, wrenches have the following types:

open end wrenches;

Ring wrenches;

Combination wrenches;

Adjustable wrenches.

Well, let's look at all types of wrenches, in order. As you can see, the topic for discussion is very, very large.

open end wrenches

Perhaps the most common type of wrench, which has become a kind of symbol of this tool. So, open-end wrenches have existed, perhaps, since the time when the first nuts and bolts appeared. The difference between these keys is that the axes of the heads of such keys are usually deviated by 15°. Previously, the shape of the horns had a familiar shape and was made according to a certain GOST. However, recently, adjustments have been made to open-end wrenches - in particular, special recesses have appeared on the horns, which allow you to fix the nut more rigidly, and therefore it is practically impossible to break the edges of the nut or bolt head. In addition, the second adjustment was the shortening of one horn, which allows you to quickly rearrange the key from one nut to another.

Also, it is worth noting that open-end wrenches can be double-horned and one-sided. Actually, they can be distinguished quite simply - on a one-sided one, the horns are present only on one side, on a double-horned one, on both sides.

Ring wrenches

Immediately make a reservation that the ring wrench, as well as the open-end wrench, can be one-sided and two-sided. The difference of this key lies in something else - namely, in the form of the key head itself. If in the previous case the wrench had horns, between which nuts and bolts are fixed, then in this case, instead of the horns, we have some “rings” inside which the shape of a hexagon is notched, which completely repeats the shape of the nut or bolt head. According to the size of the product to be unscrewed or screwed in, the appropriate key is selected. The advantage of this type of key is that in this case the possibility of tearing off the edges of the part is completely excluded, since the head is clamped even more tightly than in the situation with a conventional open-end wrench.

The disadvantage of a box wrench is one detail that should be considered when working with nuts. So, you can use a spanner wrench only if there is free access to the nut or bolt. That is, in some situations, the nut can be closed with a sleeve, or any other object. Then, it will be possible to use either the open-end wrench above, or the adjustable wrench, which we will describe below.

socket wrenches

No, you can not unscrew the nuts without free access using this wrench. In fact, it will also be impossible to unscrew the nut with a socket wrench, which does not have free access. In general, a socket wrench is designed to unscrew nuts and bolts, and it completely covers the nut during operation. Thus, adhesion occurs on all its faces. At the socket wrench, the head can have both 6 and 12 faces, and in general, this tool has several varieties - for example, they are “T” or “L” shaped, and at the same time, the head and handle will form a single structure . In another case, the heads can be removable.

Another type of socket wrench is a tubular wrench. It is made in the form of a tube, at the end of which there is a head in the form of a hexagon, and at its other end there are 2 holes where the pin is inserted. The pin that is inserted into the key acts as a handle. Also, such a key may not have a head, but simply a hexagonal hole.

adjustable wrench

It is the key with which you can unscrew the nut or bolt without having free access to it. So, an adjustable wrench is a kind of wrench in which the gap between the horns, or “sponges”, can smoothly change depending on the size of the nut you are working with. The size of the gap between the horns is changed by rotating the wheel, which works like a worm.

Such a wrench is very good in that it can be used to completely adjust the size for tightening or unwinding the nut, so it has a certain “universality” property. However, it has significant drawbacks - so, under no circumstances should you hit this key with a hammer. Also, this wrench comes into contact with the nut or bolt only on two of its faces, so the risk of stripping the thread increases. And the last drawback is that if used incorrectly or with great effort, the “worm” of the key can disperse, slip off the nut, and also strip the thread. Therefore, when working with a wrench, you need to be extremely careful and careful.

Wrench material and dimensions

There is little to say about the size of wrenches - they are measured in millimeters, and range in size from 4 m to 12 mm. This applies to small keys. Then, there are medium-sized keys - their size is from 12 to 22 mm. And, keys of large sizes - from 22 mm and above.

Much more interesting is the section on the key material. So, almost all keys are made of high-strength carbon alloys, or, as they are also called, tool steel. The highest quality keys are made of tool steel, which were made on milling machine, and then blued (such keys are black). Also, on modern wrenches, you can see the inscription "chrome vanadium", that is, it is clear that such a wrench is made of chrome vanadium. This alloy is very durable, does not deform, and is of high quality. Therefore, such keys are by no means cheap.

In the manufacture of wrenches, the process of making the horns themselves is very important, because you need to make a very accurate distance between them in order to get the right wrench size. Moreover, the horns of wrenches, as a rule, are reinforced with even more high-strength alloys, so sometimes it can happen that the horns of the wrench can be intact, and the handle can be somewhat deformed.

Well, now you know almost everything about such a tool as a wrench - about its types and materials from which it is made. This store of knowledge will be quite enough to choose high-quality keys in a tool store without resorting to the tips of a consultant who is often interested in selling them the necessary tool.

There are several types of wrenches. They are used for tight fastening of joints, including a bolt and a nut. They are made from an alloy of chromium and vanadium. In order to prevent rusting of the key, chrome plating is used.

The first key was created by Solimon Merrico, who patented it back in 1835. There are many varieties of keys, all of them are very necessary for a person for construction and repair work in everyday life.

Purpose of wrenches

If you carefully consider the types of devices in the photo, you can understand that in addition to the models found in our homes, there are many more variations of them. They differ from each other not only in form, but also in the purpose of application..

For example, a fire hydrant wrench is used for only one purpose. While the rest, say, combined or adjustable tools, can be used for various areas.

Such a variety of devices is necessary to ensure comfort in the work of not only professional specialists, but also in the lives of ordinary citizens.

A properly designed tool helps to quickly complete the repair task assigned to a person.

Types of keys

The size is usually indicated by parameters such as the distance between the jaws.. In the 19th century and early 20th century, the nominal size of the tool was most often determined by following the general parameters of the thread it created. In modern practice, there are designations based on the total distance between two planes.

Dimensions should be considered according to such indicators as the mouth (distance from one sponge to another), thread parameter (nuts), handle length. The next parameter carries a distance from 3.2 mm to 155 mm, the second from M1.6 to M 110; and the third - from 150 millimeters to 500.

Open-end wrenches one and two-sided

These keys have open ends.. Their hole is presented in the form of a U. Most often they are different in size. Such products should be used when working with nuts and bolts, which are very difficult to access. They give a lot of room during unscrewing.

Double ended ring wrenches

The device is wrapped type at two ends has a closed circuit. The product is most often used for nuts or bolts of a hexagonal shape. But in some cases it can be created in the shape of a square. The loops at both ends are the same size. Products of this type are used when open models cannot perform their task.

combination keys

Combined appliances, as their name implies, are presented in the form of a combination of a box model and an open-end wrench. They are closed at one end and open at the other. The wrench can be used to loosen bolts and nuts, and then quickly remove them with the open end.

Combined types of keys are most often used to perform combinations, as a result of which both rings acquire the same diameter.

Adjustable and adjustable wrenches

Such products are presented in an open type. They are applied only from one end. The overall size of the hole was not fixed. It may vary depending on the bolt or nut. But these types of wrenches are almost impossible to use in hard-to-reach areas.

This type of adjustable key is by far the most commonly used. The adjustable end device differs from the usual one in that the gripping surfaces of the jaws in it are shifted 15 degrees to the side with respect to the device handle. The modern adjustable socket wrench was created by Johan Peter Johansson.

Now you need to consider how to use an adjustable product:

1. Decide on the nut or bolt you want to fasten.
2. Open the rotary key while turning the screw. Check if you have opened it well so that the nut can fit completely into it: if not, it should be opened more. Make sure it is open a little more than the size of the nut or bolt itself.
3. Slide the free part of the tool head onto the nut while holding it in place. Rotate the screw mechanism so that it can grip the nut tightly.
4. Turn the device clockwise to tighten the screw more tightly, or counterclockwise to loosen it considerably. Continue turning until the nut is tight or loose enough to be removed.
5. Release the device and loosen the mechanism screw.

End models

It is customary to put the end device completely on a bolt or nut. When this kind of wrench is used, it does not need to be completely removed from the head of the nut or bolt after the turn is completed. The handles can be removed and re-inserted while the socket remains above the bolt.

Adjustable device, the main disadvantages:

1. Relatively large size, can be a significant obstacle when working in hard-to-reach places.
2. The backlash of the movable jaw does not allow the nut to be tightly compressed, ultimately, with a little effort, the wrench smoothes the corners of the nut and breaks off, at which time a person can get a significant injury.
3. Over time, the mechanism of the movable sponge wears out a lot, leading to a strong backlash.
4. The low strength index does not allow to create a large and twisting moment.
5. The need to adjust the position of the movable sponge.

The only advantage is the ability to change the distance between the jaws. But even this advantage can be negated with a socket wrench with interchangeable or bicycle heads.

Impact wrench

Types and sizes of products can be completely different. The impact type is a special thick, short and stocky device with a blocky end of the handle, which is specially designed to work with a hammer, which helps to give it more power in work.

It is used most often with large fasteners, a special nut and a font that have indication marks.

Impact wrenches are very strong, able to withstand the high force needed to release large stuck bolts and nuts. They will help when free space does not allow the use of a large device.

Hex Tool

Such a device has a hexagonal end. Tools are used during the unwinding of a bolt with a hexagonal recess at the end. The method of such work is similar to the method of operation of a screwdriver. In order to better understand the principle of operation of such products, it is worth studying the types of wrenches, especially you need to pay increased attention to the photographs of the products.

Illustrative information helps to learn more about the features of any model.

Hexagonal devices come in two forms: with L-handles and T-handles. L-shaped keys are created from a hexagonal wire, while T-handles are considered to be the same hex wire with a metal or plastic handle attached to a specific end.

Types of key and its name can also be studied in a hardware store. Most of the names of the devices come from their appearance.

Such hexagonal products have a head on a short arm and a hexagonal ball head on a longer arm. They enclose a large contact surface on the head of the screw. This reduces the possibility of heavy wear or rounding of corners in the screw.

A ball on a long arm is needed so that the key can be easily inserted into the head, which will help turn it at a certain angle, this is very important for use in hard-to-reach places.

The round shafts of the keys fit well in the hand and make the operation as easy as possible.

Since stainless steel is used for such high-quality products, there will definitely not be any problems with rust. If you noticed it on the surface of the device, then there can be only one reason. This is due to the active use of the tool to turn the screws or bolts of excess steel. The pressure after itself leaves traces or components of another metal on the stainless beak, and in this case, corrosion develops under the influence of oxygen.

balloon instruments

This type of device is used to loosen and tighten the nuts on the wheels of a car. In the United Kingdom and Austria, it is widely used as a wheel brace..

Wrenches of this format may have an L - shaped metal rod with an end product on a curved tip and a knee on the other. The capturing tip is used to remove the caps from the wheels, which are fixed with the hooks of the tips.

Gedore is very popular in the construction tools market. It creates high-quality products that are actively used by motorists from all over the world. Appearance The first Gedore sets will definitely appeal to every car enthusiast.

Another common species, sometimes called the key spider, is represented as a cross with spaced nests at each of the four ends.

It is best if the bolts (or nuts) are tightened with a torque tool. These devices are much cheaper. Installing wheels while using them requires more force. Excessive force can make the nut very difficult to remove. In addition, the uneven distribution of force between the nuts and the device itself can lead to deformation of the brake rotor if the car has disc brakes.

For this reason, balloon tools are best used only to remove the nuts from the tip, and not to tighten them. In practice, such a rule is very often not observed even by professional mechanics themselves.

For every auto mechanic or ordinary person whose profession is inextricably linked with the use a large number tools, you can buy cutlery in the form of wrenches. Such unusual gift they will definitely like it.

tubular model

1. The tubular device is represented by a tube, at the ends of which there are hexagons, special holes are made in the tube for a knob (a rod that plays the role of a lever). The hex size at the end of one key will vary considerably. Equipment and some machines, including cars, are sometimes equipped with such simple products.
2. In some cases, the manufacturer bends the pipe, while obtaining an L-shaped tubular device. They have the same hexagon index at the end of one key, and the functionality of the positions is just like that of L-shaped end devices.
3. A type of tubular device is considered to be a candle (for automotive spark plugs), it has a hexagon on one side.

In the cavity of the pipe, there may be protruding parts of threaded connections, for example, strongly protruding parts of a candle.

Products equipped with a ratchet

Cap and end products can be modified together with a ratchet mechanism (in other words, combined with a ratchet). The main advantage of such a ratchet wrench is that it does not need to be thrown. Another important advantage is the small angle at which the wrench is turned to carry out the screwing and unscrewing of the nut.

Ratchet mechanisms differ significantly from each other, for example, in terms of the number of teeth, if the mechanism has 72 teeth, then 5 degrees will be enough to turn, if 50 teeth, then 9 degrees, and so on. The formula for calculating is the angle of 360 degrees divided by the number of teeth. This is very important when working in very cramped conditions.

The main disadvantage of the device is the ratchet, which is considered its weak point, as it can easily break under load.

open end wrenches

There are quite a few types of wrenches, as they are needed for different nuts, bolts and are used in different situations. Somewhere it is more convenient to use one type, somewhere else, it all depends on the size of the nut, how it is located, and how to approach it. Consider all the main types of keys, their sizes, shape, advantages relative to each other. There are many manufacturers in this market, therefore, prices vary greatly. We can say that there are no high-quality and cheap keys. A good thing is not cheap, this applies to them.

Open end wrenches(on 1 photo). This is probably the most commonly used type. It is called so because its ends resemble horns. Sold both in sets and individually.
These keys have two different sizes at the ends. For example, 8*10, 10*12, 13*15 and so on. The size range is quite wide, ranging from 4mm to 55mm.

One-sided open-end wrenches.

They are mainly used in industries, it is unlikely that this will be useful in everyday life. Sizes start from 36mm, maximum 95mm. You can work with force by putting on one side of the key metal pipe, which greatly increases the tightening force.

Ring spanners are double-sided.

They have two different sizes at the ends, for example, 17*19, 19mm*22mm and so on. Sizes from 6mm to 55mm. Unlike open-end, the ends are in the form of a ring, which allows you to turn the nut without breaking off, without constantly rearranging the key, and it will not break.

Single ended wrench.

It has a ring on one side only, for greater tightening force it can be used in conjunction with a pipe. Sizes from 30mm to 50mm.

Ring impact wrench.

Has one ring. Unlike simple ones, drums are noticeably thicker. There is a special place for hitting with a sledgehammer or a hammer, they are mainly used for powerful tightening. Available in sizes from 27mm to 105mm.

On the one hand, these have a ring, on the other, the shape of an ordinary open-end wrench. The dimensions are the same on both sides. For example, 10*10, 12*12, etc. Combines the advantages of an open-end wrench and a box wrench.
Minimum size 5mm, maximum 32mm.

socket wrenches(tubular).

Good in cases where the nut is deep in the part, and it is simply impossible to crawl with other keys.
As a rule, they have two sizes on different sides. They are simply in the form of a tube, this can be twisted with a simple screwdriver, there is a special hole for this, they are L-shaped, they resemble the Latin letter L in shape, it can be twisted without the help of foreign objects, just by hand, as the shape allows.
This also includes candle keys, also made in the form of tubes, especially for spark plugs.

adjustable wrenches.

Its main advantage is that it adapts to many sizes, has sliding lips. There are several types, small and large, up to 19mm, up to 30mm, up to 35mm, up to 46mm. Often the nut has a non-standard size, or the necessary key was not at hand, then the adjustable wrench will completely solve the problem.

They are universal, the jaws are sliding, so they cover several diameters at once. Dimensions - from the smallest zero number, capable of clamping a maximum diameter of 28mm, to the largest number 5, this will already cover a 120mm pipe.
According to foreign nomenclature, sizes are marked in inches. For example, a key for 1 inch, 1.5, 2, 3 inches.
The shape of the jaws is L-shaped (straight) and S-shaped (rounded jaws). For capture round blank an S-shaped lip is better, as there are three points of contact, if the workpiece is flat, an L-shaped lip is better.

Star keys(Torx).

They come in the form to twist faster, there are also simple ones for manual use. Typically used for repairs household appliances, in cars, cell phones.
I have sizes from T5 to T50. The smallest ones (T5, T6) are sold only in sets for cell phones.

Hex Keys.

Applicable for the repair of equipment, furniture assembly (4mm key for confirmation - furniture self-tapping screw). There are in sets and piece. Sizes from 1.5mm to 24mm.

sparkless keys.

Very specific. They are used only in explosive industries. They do not give a spark when they hit metal or fall, if the work is connected with gas, then these are used. They are easy to recognize by their color. It can be yellow, or the color of copper is reddish.

Even a person who is far from technology often has to unscrew and tighten screws, bolts, nuts (hardware - this is how these metal products are often abbreviated) with a tool intended for this - wrenches. Each key is marked with the size of its working part, simply - the pharynx. But the value corresponding to it - turnkey size - denoted in technical reference books by the letter S (the distance between opposite parallel faces on a nut, bolt head or screw) is not listed on any fastener. As a rule, these data are not available in the operating and repair instructions attached to any technique, even in the symbols and drawings, although there is plenty of other information about fasteners in them: both the thread size and its pitch are indicated, sometimes the length and even type of heat treatment, often tightening torque. But basically these data are constructive, and they are needed for the manufacture of parts. During adjustment, repair or assembly work, the above thread parameters, except for the latter, turn out to be unclaimed. For a mechanic, it is much more important to know with what size of the throat a wrench is needed for the head of one or another screw or bolt and nut (or, as the professionals say, “wrench for how much”).

When the nut or bolt head is in plain sight and in an easily accessible place, it will not be difficult to determine “how much” a key is needed - an experienced techie will recognize this at a glance, and an inexperienced one can “calculate” with a caliper or by selecting keys: from two -Three times this is usually done successfully.

If the fastener is in a hard-to-reach place, and even “behind the eyes” (which happens very often), then you have to touch the size of the turnkey hardware head, when even a professional can easily make a mistake. Trouble will not happen if the master tries to work with a smaller key - he simply will not fit on the head. If the key turns out to be large, then “cutting off” the edges of the head with it, as they say, is a couple of trifles. In addition to the fact that the part will be irreparably damaged, then unscrewing the fasteners even with a special tool will be a considerable problem.

To determine the “turnkey” size “behind the eyes”, it makes sense to refer to the information on the thread of the fastener specified in the instructions. After all, according to GOST, each thread corresponds to two close sizes of the turnkey fastener head: the main and the reduced one, and the difference in their values ​​is small. On average, the turnkey size is approximately 1.5 times the outer diameter of the thread (see Table 1) and you can already focus on it.

Table 1. Correspondence of the dimensions of the turnkey fastener to its nominal diameter metric thread
Nominal diameter of metric thread		4	5	6	8	10	12	16	20	22	24	30	36	42	48
Turnkey size	S main	7	8	10	13	17	19	24	30	32	36	46	55	65	75
	S	-	-	-	-	12	14	17	22	27	32	41	50	60	70

And although the reduced turnkey size is assigned by designers less often than the main one, it is necessary to try to unscrew the fasteners “behind the eyes” for the above reasons with a smaller key: if it doesn’t fit, then you can safely work with a key corresponding to the main size - it will not break (of course, provided that the fasteners are not rusted). The keys are usually also made according to the same principle: at one end of the pharynx (open - for open-end, closed - for socket and ring keys) corresponds to the main size of the head of the fastener, at the other - reduced. Only combined ones fall out of this series, in which at both ends the pharynx is of the same size, only one is open, and the other is closed (circular), and wrenches are adjustable.

Sizes and types of wrenches

When working with fasteners for their safety, the tool is of the utmost importance, therefore, only serviceable keys should be used: their pharynx should not be expanded, and the lips should not be wrinkled. Wrenches with such defects must be removed from the working set. In addition, seemingly similar tools differ significantly in the quality of the metal, the profile of the jaws. The last condition directly affects the distribution of forces on the edges and edges of hardware.

Fasteners are designed for a specific tightening torque when assembling the product. However, often the efforts during disassembly, especially of “stuck” or rusted threaded connections, exceed it many times over. In these cases, it is better to use the appropriate socket or ring (professionals call them ring) wrenches, and not open-end wrenches. Moreover, you cannot use an adjustable wrench, as well as when unscrewing small (less than S10) nuts, bolts and screws.

If the edges of the fastener are severely damaged by corrosion or for some reason turned out to be “rolled up”, in order to still unscrew it, it is necessary to grind off the turnkey edges by a “number” less. Then, having impregnated the threaded connection with a special liquid (or, in extreme cases, kerosene) to soften the rust and after waiting for time, try to unscrew the part again. Another way (but not the last) to unscrew a bolt or screw with a damaged head is to make a slot between opposite faces for a strong screwdriver and try to unscrew the fastener with this tool. And finally - use a pipe wrench for this. By the way, in the nomenclature of the latter there are now those that do not damage the edges and edges of fasteners even at high unscrewing torques. For small nuts, special pliers can be used.

When you have to deal with the adjustment and repair of the same equipment (for example, a personal car) on a regular basis, it will be useful to compile a table of turnkey sizes for fasteners of the main adjustable units, devoting special time to this or as you turn to adjusting one or another mechanism or unit.

Table 2 shows the dimensions for the wrench of the main and adjusting threaded connections for the VAZ-2105 car.

Table 2. Some fasteners and their turnkey dimensions in VAZ vehicles
Name of units and fasteners	Fastener thread	Turnkey size
Engine, transmission
Flywheel housing screw	M6	10
Nut of fastening of the distributor of ignition	M8	13
Valve cover nuts	M6	10
Screw of fastening of the oil pan	M6	10
Silencer clamp bolt and nut	M8	13
Screw of fastening of the pallet of a crankcase of a transmission	M6	10
Nut of a tension of a belt of the fan of a pomp, generator	M10	17
Nuts of fastening of a cover of a head of cylinders	M6	10
Battery terminal nut	M6	10
Battery bracket nut	M8	13
Steering, brake, suspension, wheels
Castellated nut of fastening of a finger of steering draught	M10	17
Tie Rod Clutch Bolt	M8	12
Nut of a bolt of the coupling of steering draughts	M8	13
Nut and locknut of adjustment of a manual brake	M8	13
Nut of a hairpin of fastening of the lower spherical support	M8	13

Since it was about cars and car wrenches, it is worth noting that on a special account in the tool kit of the Zhiguli (and other cars) the so-called "balloon" "for 19" and "candle" "for 21" wrenches.

The first one is made quite peculiarly and stands out from the whole set of wrenches. It is recognized even by those who are not familiar with technology: it is cap-shaped, with a curved lever handle, the end of which is made in the form of a screwdriver sting. Once upon a time, with the help of this key, chrome wheel covers were removed, which are no longer installed on modern cars. It would be advisable to sharpen it a little and thus have a strong screwdriver in the kit. In addition to loosening and tightening wheel bolts, this wrench can also be used when working with other relevant fasteners. If necessary, the wheel bolts can also be unscrewed with a conventional (box and even open-end) wrench "19".

The second - a "candle" wrench in appearance is similar to similar tubular socket wrenches with the same diametrical hole for the knob. It even retains a ratio of 1.5 of the diameter of the turn-off thread (14 mm) to the distance between the opposite faces of the key (21 mm). If we turn again to table 2, it will become clear that the key is non-standard, and there is no special and other wrench with the same size in the kit. The thread on the candle, although standard (14x1.25), is one of the non-recommended ones.

And about one more wrench - the usual open-end wrench "for 10". This wrench, like a fire extinguisher, is always better to keep "at hand" - as they unscrew the nuts of the battery terminals. After all, if necessary, for example, in case of a short circuit in an electrical circuit or (which has also become relevant now) to turn off an alarm that has worked for no reason (if it does not “obey” the key fob), this must be done very quickly.

It should be noted that in the automotive tool kit there are wrenches for far from all sizes of fasteners. Therefore, when you need to crawl under a car (in a pit or overpass), it will not be superfluous to check whether everything necessary tools taken with them, otherwise you will have to crawl out from under it with nothing. The same must be done if you are going to disassemble some assembly or assembly for repair or maintenance. In addition, very often some kind of universal and even special devices are required to disassemble the nodes without damage. Without all this, disassembly may be impossible or even in vain.

One remarkable moment: fasteners with a turnkey size of “13” appeared in our country along with the Zhiguli car, the prototype of which, as you know, was the Italian FIAT-124. With their appearance, hardware with wrench sizes “by 12” and “by 14” has lost its position.