Pipe wrenches: main types, advantages of use and subtleties of choice

Representing an improved version of the adjustable wrench, the gas wrench, or as it is also called, the pipe wrench, is designed to work with pipes, as well as any other parts that need to grip and hold connections without special edges. Often used by professional plumbers. A little less often, but quite regularly, this tool is also used in car services, in production and at home.

History of origin

In general, references to wrenches have been found since the 15th century. Mass production and use began only in the 19th century, with the beginning of industrial production. In the same 19th century, a wrench with a variable size (adjustable jaws) was first invented. Then an adjustable mechanism arose, from the design of which, by adding a worm gear, the gas mechanism we are accustomed to today emerged.

The credit for inventing the pipe (gas) wrench is given today to the Swede Johan Petter Johansson (Johansson), who modified the adjustable wrench in 1892 . Mass production of gas keys under the Bahco brand is also organized in Sweden. These keys sold quite successfully. Therefore, this type of instrument is often called Swedish or “Swedish”. According to Russian GOST, this type of wrench is designated as a pipe lever wrench (KTR).

Reliability as a cult

With all the variety of options and modifications of keys, the general requirements for this tool have not changed over the past decades: precise and strong grip, comfortable position in the hand, reliability and, of course, durability. As the scope of tool use expanded, it also became clear that wrenches must withstand severe temperature changes, exposure to chemically aggressive environments, abrasive particles, etc. When manufacturing tools designed to work in such extreme conditions, special attention should be paid to materials and production technologies .

For those applications where the weight of the tool is critical (mobile crews and installers working at height), manufacturers offer lightweight versions of wrenches made of aluminum alloys. “Of course, this does not affect the strength characteristics of the tool in any way. Designers calculate the optimal cross-section of the handle so that with minimal weight it can withstand maximum effort, says Maxim Shagalin, head of the sales department at Profi (St. Petersburg). — At the same time, such a key is about 40% lighter than a regular one. If you have to use this tool for several hours a day, there is no doubt that you will quickly feel the difference.”

According to Valery Andreev, General Director, the ergonomics and reliability of pipe wrenches affect not only the speed and quality of work. To no less extent, the injury safety of the tool depends on these characteristics. An ill-conceived design of a key or the use of unsuitable materials and technologies in its manufacture can lead to emergency situations and serious injuries to workers.

Types of gas keys

If we consider all variants of devices intended for working with pipes, couplings, bends and other parts without special edges to be pipe, then the following types can be distinguished:

• pipe with self-gripping;
• chain pipe;
• drill key for core pipes;
• lever gas (Swedish);
• adjustable pipe (American);
• sheet piling and pipe pliers.

The most common are the lever gas wrench and the adjustable pipe wrench . Lever - these are two levers connected by a hinge, one of which is stationary, the second moves to adjust the diameter of the grip. In this case, both levers are a handle on one side, and jaws on the other side. The adjustable one consists of two elements, one of them is a handle, the second part is attached to it using a thread, which moves along the handle.

In addition, these tools differ in the shape and location of the gripping jaws. Straight jaws can be positioned at 45° or 90° relative to the axis of the handle. Also, the working surfaces are made S-shaped, they are located at 45°. A wrench with an S-shaped jaw holds the pipe much more reliably, since contact occurs at three points on the circle, and not at two, as with flat “jaws.” The jaws of pipe wrenches are also removable, which allows you to extend the service life of the tool by replacing worn out working surfaces.

Strap and chain wrench

Wrenches of this type are used much less frequently in everyday life or household work, since such wrenches are designed for working with large pipes with huge diameters. As a rule, such pipes are not used in home communications, so there is no need in this case, in this vein. But, they are successfully used in enterprises and factories, in public utilities, where they find their true application. Such a wrench has a strap or chain (depending on what kind of wrench we are talking about), which is used to grab the pipe.

Key sizes by numbers

The most common classification of the dimensions of “Swedish” keys is the breakdown by numbers. The numbers of the described tool are divided depending on the diameter of the pipe that can be worked with by this device, and on its total length. The key parameters are presented by number in the table.

There are references to gas keys No. 6, 7 and more, but they are very rare. The most commonly used sizes are No. 1, No. 2 and No. 3 .

How to use a gas wrench?

Before you start working, you need to determine the diameter and select the correct number. Even if the pipe does not have special edges, the pipe wrench must cover at least half of its diameter. Work with the device is performed according to the following algorithm:

1. It is necessary to inspect the “teeth” of the key jaw. If they are bent, it is better not to use them.
2. If the part is chrome or has a decorative coating, it is better to protect the place of contact with the key with cloth or cardboard.
3. When a unit cannot be dismantled or disassembled, it should be cleaned of rust or paint.
4. It is not recommended to use additional leverage if efforts do not bring results. The key might just break.

Advantages and disadvantages

A well-thought-out, high-quality tool is always used with pleasure by both professionals and amateurs. In this sense, the design of the gas key has a number of advantages:

• the ability to fix the pipe and clamp the thread without cutting special edges;
• ability to work in hard-to-reach places;
• simple design, maintainability;
• high-quality materials used in the manufacture of tools ensure reliability and long service life (naturally, if the tool is branded);
• Great physical force is not required to clamp the pipes, you just need to choose the right size;
• special teeth on the jaws cling to a smooth surface and make it easier to fix the part.

The main disadvantage is the possibility of crushing and even breaking the pipe. However, it should be mentioned that this only happens when the tool size is incorrectly selected and the adjusting nut is overtightened, as a result of which the compressive force exceeds the strength of the part (coupling or pipe).

Lever pipe wrench

This type of gas wrench consists of fastened levers. One key is completely stationary, and the second adjusts the gripping area of ​​the jaws.

An important factor is that such a pipe wrench has replaceable jaws, which means that you can change the grip angle of the lever. This function of the key makes it a durable tool both at home and at work.

A lever pipe wrench can be used by both a beginner and a master, because this tool is universal in use. It is capable of simultaneously performing pipe fixation and thread clamping.

The key is a lightweight design, so it won't take you long to think about how to use it. Unlike some other types of gas wrenches, you should not use physical force when using a lever wrench.

The main rule is to choose the right size and correctly install it on the pipe. In this case, the pipe itself should not be damaged. Therefore, you should be careful not to accidentally press and ruin the entire work.

If you purchase this type of gas wrench, you will notice that it has a low price, but you can’t call it low either. If the price is too low for such a tool, then it was made from low-quality products. You should trust only trusted manufacturers.

If you need a key in everyday life, then you can get by with a budget option. And if it is required for professional work, you should pay more for the durability of the keys.

English adjustable wrench

Edwin Beard Budding (1795-1846) invented the so-called English screw wrench in 1843.

An image of a Budding wrench in an advertising leaflet from the first half of the 19th century.

In this key, the span of the jaws was adjusted with a special bolt.

Edwin Bird Budding

Although Budding is mostly remembered for the invention of the mechanical lawn mower in 1830.

Lawnmower invented by Edwin Budding /photo sciencemuseum.org.uk/

The image of an English adjustable wrench is still used in the Highway Code on sign 7.4. "Car maintenance."

English adjustable wrench on a modern traffic sign

What types of keys are there?

Main types of wrenches:

• Carob;
• Caps;
• Combined;
• Adjustable;
• Special:
• End

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For household use

Separately, it is worth mentioning gas wrenches, which are used to work in hard-to-reach places, for example, near the sink siphon. These are the so-called Stillson wrenches, for example, the Stillson 1/2/12 Anchor pipe wrench. The peculiarity of these tools is that, thanks to double springing, they independently grip the part, and the upper hook prevents the tool from accidentally opening or rearranging the jaws. Therefore, even if the plumber does not see how the jaws of the wrench are located on the pipe, he can be sure of a reliable and correct grip.

General rules for using wrenches.

To avoid damaging the part you are securing the joint with and injuring yourself, always select a wrench that is the right size for the nut or bolt head you are tightening or loosening. Make sure the jaws of the nut tool are firmly seated on the fastener before applying force. If you take them into account, the key will not fall off, and if it does, you will not have to swear because of abrasions.

When using a wrench, it is better to use a pulling rather than a pushing motion (see picture on the left), and you will generally find it easier to position yourself to pull rather than push. This ensures that you won't have your fist cut off if the tool comes off. If you have to push, use the heel of your palm so that even if the key comes off, you won't get hurt.

Do not lengthen the lever arm
with a tube, use a longer wrench. You may have seen your dad put on a long piece of pipe to lengthen the lever arm and tighten the fastener tighter. Avoid using "extensions".

First, they can damage the key by bending the handle or bending the head.

Secondly, because of the extra torque you get with the extra leverage, you run the risk of stripping the edges on the nut, especially if you don't have the right socket.

Finally, there is a possibility that the extension will slip off the handle when you turn it, causing harm to you or others. If you encounter a stubborn nut, apply a little penetrating lubricant (such as Liquid Wrench) to the threads, wait a few minutes, and then try to loosen the threads.

Do not use damaged keys

. If the handle is bent or the jaws look wider than they should, do not use it.