How to choose a construction knife. Construction knives. Types and selection criteria Types of knives by purpose

A tool such as a construction knife is designed for cutting cardboard, cables, and a variety of finishing materials.

Types of construction knives

folding;
Pocket;
with replaceable blades.

The main task of such knives is to solve issues during construction and installation work, finishing and even gardening. It all depends on the type of instrument. It can cut fabric, plastic, paper as well as wood, drywall, wires and thick cables. In addition, wallpaper, floor coverings are easily cut, wires and leather products are cleaned. And thanks to the variety of cutting parts, patterns on linoleum are easily cut out when laying it. Blades are made of stainless steel or alloyed. They are very easy to sharpen and, if necessary, replace. The handle is mostly plastic and covered with insulating materials such as rubber. Otherwise, it is possible to use rubberized plastic.

Types of knives by purpose:

cutting wallpaper, leather products, linoleum and curly cutting of materials - a corner knife with replaceable round blades;
cutting a special coating (carpet) - a special knife;
wire or cable cleaning - folding or mounting knife.

Criteria for choosing knives
First you need to choose the size of the cutting part, for the convenience of cutting materials. Then pay attention to the ability to sharpen or change blades. The strength of the knife directly depends on the thickness of the cutting parts (the recommended width is 25-30 millimeters). It is also better if the tool is equipped with guides that allow you to use knives for cutting very thick or layered materials.

There are blades coated with titanium, which provides a fairly long life of the cutting parts. A plastic handle with a thermal insulating property will ensure safety when working with electrical wires. The blade has markings that allow you to adjust the cutting depth. Or there are segments that can be broken off. For example, if one part of the blade becomes dull, it can be broken off, and the next part will be very sharp. The blades are sharpened with a special method to cut deeply and smoothly.

A construction knife based on a replaceable segmented blade is quite popular in construction and repair work. Moreover, the blades of such knives do not need to be sharpened, but only broken off and replaced with the next segment.

A technical knife is useful to any master during repair and construction and installation work for cutting cardboard, plastic, drywall and other materials. A quality tool can last more than one year, while a high price is not necessarily a criterion for reliability. A durable and convenient construction knife can be found even in a modest price category, having understood the main parameters of the tool.

Frame
The body of a construction knife can be plastic or metal. The first is easier to carry, but less impact resistant. Both materials are available with a rubberized finish that reduces tool slippage in the hand.
The main difference between a construction knife and a clerical one is the presence of a metal guide “peeping out” from the body. It fixes the blade, so that it does not cut into the body when handling dense materials. In addition, the guide can be used to hold the tool with your index finger for greater cutting precision.
Pay attention to the thickness of the guide and the play of the blade relative to it. Many suppliers began to make such elements for "decorative purposes". The guide should work - be strong and securely hold the blade.
Structurally, construction knives are divided into mechanical and "automatic". The latter are equipped with an automatic replacement blade feed system, thanks to which you can replace a worn element at the touch of a button. Many knives have special compartments for storing replacement blades: this makes the tool more mobile to use, and also allows you to store additional items without fear that they will be lost or become unusable.

Blade
A feature of construction knives is the absence of the need to sharpen them. The blade blade consists of segments that are easily broken off with pliers if the knife becomes dull. Segmented blades can be updated in this way from 7 to 13 times, trapezoidal - designed to work with the most dense material - only 2 times.
There are three types of steel traditionally used for construction knife blades:
CS - tool steel, which is designed to work with paper, wallpaper and cardboard. Blades made of this material break the fastest.
SK5 - professional steel for working with plywood, linoleum and drywall.
SK2 is the strongest and most expensive steel.
In some cases, the blades are blued to prevent corrosion of the metal. Such material can be easily distinguished from standard steel - the blades are black. So, as an experiment, a line of burnished construction knives was launched by the Russian brand of hand tools VIRA.

Retainer
Intermediate fixation of the blades of construction knives can be carried out in several ways: automatically (auto-lock), twisting (twist-lock) and by pressing a button (push-lock).
The most convenient is the automatic type of lock, when using which you do not need to perform additional actions, however, professionals prefer construction knives with a twist-lock blade feed, considering this type of lock to be the most reliable. Button knives are the golden mean between convenience and reliability.

The concept of "mounting knife" includes a set of tools designed to perform their main function in the technical and construction fields. Among this line there are specific designs, as well as universal tools.

Specially designed knives are designed for a specific job and are not suitable for other uses. An example is an electrical knife with a heel. Universal types are usually used in a wide range of jobs and even for domestic purposes.

The main difference between a mounting knife and a household knife is its technical suitability for performing mounting and construction tasks, convenience and speed of use in a given area.

Types of mounting knives

All industrial knives can be divided into two broad categories:

Construction and assembly
Electrical knives.

Modern construction knives are designed with removable, replaceable blades. The cutting part is also segmented with the possibility of breaking off the segments. This technical solution allows you not to waste time sharpening the cutting blade and perform the work extremely quickly. The handle of the mounting knife of professional models has rubber pads for better fixation of the tool in the hand. The knife can be stored in the pocket of overalls during operation, as it has the function of hiding the blade in the handle.

Electric assembly knives consist of a handle and a steel non-replaceable blade. They come in different types to perform certain operations and work:

Cable knife. It has a straight shortened blade, often covered to the level of the cutting edge with insulating material. Apply this
Electrical knife with a heel. The blade is curved like a beak. At the end it has a welded element in the form of an oval heel. This knife is used for stripping primary insulation from multi-core cables. Its design does not allow breaking the wire insulation in the bundle.
Knife assembly universal. Folding knife design like a penknife. In addition to various stripping blades, it also has an awl and screwdriver tab. Designed to work with de-energized wires.

What can be done with a mounting knife?

The applicability of a construction knife is very wide. In addition to the usual operations of cutting ropes, fabric, hose, wires, sharpening pencils, he can:

Cutting drywall. Thanks to a strong and sharp blade, soft plaster and thick cardboard are easily cut and broken at the cut point.
Cut linoleum and carpet. It is convenient not only to cut the floor covering into segments, but also to make a curly cut and adjust it in hard-to-reach places.
The mounting foam knife removes excess easily and quickly.
Work with foam, mineral wool and other insulating materials.
Act as a wallpaper knife.
Cutting film, both ordinary and all types of waterproofing and vapor barrier materials.

The scope of the electrical knife is limited to the field of energy and voltage tolerances. Typically, professional cutting tool insulation can handle up to 380 volts and up to 200 amps.

Another type of cutting tool for technical purposes is a mounting knife-scalpel. This device also has a handle and a blade, but they are made entirely of high grade tool steel. Scalpels of this type are designed to work with electronic circuits, or rather the repair of components and blocks. They are also used for cutting current-carrying tracks on a printed circuit board.

How to choose a good mounting knife?

A quality construction tool has the following characteristics:

The presence of a strong handle, equipped with rubber pads or a relief surface for ease of holding in your hand.
The presence of a mechanism for rigid fixation of the blade.
Blade guide made of durable steel. If a segment of the blade breaks, the guide should not be deformed.
Convenient system for changing the cutting element.

If you extend the blade of the knife halfway and, pressing on the handle, make a cut, the blade should not move up much, but should be in line with the handle.

The professional electrician's mounting knife has a one-piece dielectric handle without any metal inserts. The voltage limit may be indicated on it, or this limit must be in the technical specification of the product. The knife is sold initially sharpened, and sometimes steel markings are indicated on it. On modern good models, there is a blade protection casing. The blade must be free of nicks and burrs.

Caring for a professional knife

A construction knife does not require sharpening, but it still needs care. It consists in removing particles of building materials, dust and dirt from the blade extension system. It is also advisable to change the cutting elements that have begun to rust in time to prevent corrosion of the guide. Otherwise, it is risky to cut expensive wallpapers with a rusty tool. In general, it is undesirable to hide the wet blade of a mounting knife in the handle.

An electrical knife, on the contrary, requires periodic sharpening. It is better not to allow the blade to become seriously dull and to bring it down after each voluminous work. In the process of sharpening, you can not change the angle of the bevel of the blade. Store the tool only with the protective cover on. To keep the knife from rusting, it must always be coated with machine oil.

Conclusion

Three rules for choosing a quality tool, including a mounting knife:

Professionalism. A connoisseur of his craft knows what tool he needs for work.
Observation. Anyone who values strength and energy will not use an uncomfortable tool.
Generosity. Those who strive to develop their business are always ahead and do not spare money for the best technologies and tools.

Every self-respecting person, one way or another referring to the construction fraternity, has his own construction knife with interchangeable blades. It can come in handy in any situation, whether it's opening a bag of putty or cutting a sheet.

How to choose a knife?

In order for a mounting knife with interchangeable blades to serve faithfully, it is required to initially select it according to the correct parameters, which, however, everyone sets for himself. Here's what to look for when buying:

the most important thing is that the retractable mechanism in the construction knife should work perfectly. Indeed, often the speed and coherence of the work process depends on this;
construction knives with a retractable blade should be without various "bells and whistles" in order to perform the simplest function - to cut;
the weight of the knife is of great importance - the lighter it is, the more convenient it is to carry it with you, putting it in your pants pocket.

You should pay attention to the knife slider - if it is plastic and has a rather dubious appearance, then most likely it is not a construction knife, but a clerical knife, which is not suitable for applying force. Due to pressing, the mechanism breaks down very quickly and ceases to fix the blade.

A knife with a plastic wheel is already better if you do not clamp it too hard. After all, if you pull it once, you simply can’t unscrew it the second time, and you can safely throw the knife away.

The most durable of the knives for construction work presented in the hardware stores are those equipped with a metal wheel and the knife itself is also made of metal. But when buying, you should be careful not to accidentally buy a knife made of mild steel, but stainless steel will be just right.

The most popular is a knife with replaceable blades of 25 mm in size - it is powerful enough and suitable for most jobs. But the blades for a construction knife of 18 mm are thinner and will fit only for small work - sharpening a pencil or cutting wallpaper.

How to choose a knife?

Advantages of this type of knife blade

Thanks to the long blade, they can be used very flexibly, such as cutting through even thicker materials such as foam. The blade is fixed in the appropriate position that they need for certain jobs such as removing cables.

The disadvantages of incisors are

In case of lateral forces, the blade can break very quickly and injury can occur. Because the blade does not retract into the housing, there are many accidents in practice when users move around with the blade free-standing or leave it extended. By simply breaking the front segment, you cut the blade quickly and conveniently. . While some of the cutters are also known as carpet knives, a carpet knife is always equipped with a trapezoidal blade or hook.

the most important thing is that the retractable mechanism in the construction knife should work perfectly. Indeed, often the speed and coherence of the work process depends on this;
construction knives with a retractable blade should be without various "bells and whistles" in order to perform the simplest function - to cut;
the weight of the knife is of great importance - the lighter it is, the more convenient it is to carry it with you, putting it in your pants pocket.

The switches are too quickly out of control when side forces are too high, so these cutters are not suitable for heavy cutting. Thus, the carpet knife has a replaceable trapezoidal blade or hook blade. Duden refers to a carpet knife as a knife with a replaceable blade.

Disadvantages of cutters to protect hooks

Maximum safety of your sales and / or production goods from damage caused by the blade. Cutting with cutting knives should only be done 1-2 times, as they must be guided at the correct angle to the cutting material. Since you are only cutting off a very small area of the blade, only this area is worn out and the blade needs to be replaced more often, such as a trapezoidal blade carpet knife.

Maximum safety for the user from any cuts.
Only one knife for all activities.
Blades feel faster.

Other names for this type of cutting knives or cutting tools are also deburring shears, hobby knives, hand knives or model knives.

A knife with a plastic wheel is already better if you do not clamp it too hard. After all, if you pull it once, you simply can’t unscrew it the second time, and you can safely throw the knife away.

All knife functions can be found. The essential feature of scalpels is a very thin handle that resembles a pencil. Therefore, scalpels are particularly suitable for precise incisions. Another feature is a very varied selection of different blade shapes.

In addition to the medical sector, the scalpel is also used as a deburring machine in manufacturing plants. While the scalpel blade is optimized for maximum sharpness in the medical field with a very short lifespan, spare blades for the manufacturing industry are optimized for long lifespan with relatively high sharpness. The material used for the scale knob is usually stable aluminum partially coated with a soft trowel.

A utility knife is a useful tool for a wide range of tasks. With it, you can strip the cable from insulation, cut linoleum, wallpaper, carpet or other materials. Of course, in order for the product to serve for a long time, fulfilling all the duties assigned to it, you need to responsibly approach the choice.

For medical scalpels, the blades are the same for all manufacturers. Unfortunately, however, you differed from manufacturer to manufacturer in connection with mounting or assembling knives. Scalpels for industry or hobby areas also have different perforations and, above all, strengths.

Benefits of scalpels

Therefore, you must make sure that these blades fit into your handle. Just send us a photo of your handle and your blade and we'll be happy to advise you on the right choice.

The disadvantages of scalpels are

The risk of injury is very high as the blades are very sharp and the knives have no protective mechanics. Heavy cutting jobs, such as cutting cardboard boxes, cannot be done with a scalpel because the cutting edge breaks too quickly. You have bought a toolbox but you don't know what to put in it.

Construction and stationery knives: a competent approach to purchase

So, in addition to the price, the main attention should be paid to the following details:

Design. A knife with a retractable blade is convenient for a wide range of jobs that do not require too much load on the cutting part. A tool with a fixed blade will allow you to cut thick material without the risk of breaking the blade. Specialized wallpaper knives require a ruler on the body for maximum work accuracy.
Blade features. The thicker the blade, the stronger it is. For products with retractable blades, the presence of segments that increase the operational period and increase safety is considered mandatory.
General quality. The handle must have rubber inserts for ease of use, preventing the tool from slipping out, the locking mechanism must firmly hold the blade, gaps are unacceptable. For greater durability, a titanium coating is sometimes applied to the cutting edge, which retains its sharpness for a long time even with constant work with cardboard and other cellulose-based materials.

Construction knives in sheaths, retractable models - all this is presented in a wide range in the Leroy Merlin network. We cooperate exclusively with the best suppliers, and therefore all products are certified, durable and safe to use. Attentive and qualified sales consultants are always ready to help customers buy the best knife model with delivery!

You have some elements that allow you to tinker. But what are the main tools for ownership? Before buying a hammer, make sure you are comfortable when you are holding it. You'll know when you're trying to hit a 3/4 nail with a 16 oz hammer, or push hard on your thumb. You will use it at least once a week. Choose from a 25 foot tape with both metric and imperial measurements. Both are commonly used in construction.

It is important when you need to install a storage shelf, place a refrigerator, washing machine, or even a bed. Your square, as its name suggests, will help you place everything correctly. An ego-type wood saw with an 18-inch blade will make the job easier. Choose a combination saw for cutting and tearing. This requires a few shortcuts, but it's easier. Hacksaws, good quality, you will be more than useful.

Surprisingly, the knife is used for its intended purpose not only in the kitchen, and not exclusively by a housewife. A builder needs such a device no less than a hunter, moreover, it can be useful in any field of application. Therefore, in this publication we will discuss an atypical hand tool of the builder.

Varieties of knives

In the construction industry, knives are used that have special blades sharpened in professional conditions for those purposes so that they do not dull so quickly from interacting with hard building materials. They can be divided into universal and marking handy devices.

Let's start with marking devices. The name of the type corresponds to the specifics of the application, that is, such a tool is designed to determine the installation line. The work of this type of device is especially active when laying linoleum. The main feature of marking tools is the cutting element. The cutting part in such devices is sharpened exclusively on one side, which is why the tool can be freely pressed, for example, against a ruler, and marked along the plane.

The generic type is used everywhere, as the name suggests. Such a device can cut absolutely any type of building material: foam, cardboard, wallpaper, linoleum, and more. Such a tool is inherent in the property of mobility, since it contains spare blades that can be put into action at any time. For example, when the point becomes dull, the next one is immediately put forward to replace it.

A permanent place for a hand-held cutting device, most often, is a narrow pocket of overalls, a belt bag, or a special sheath that is hung on the lower back or on the leg. We will talk about the scabbard below, and we will explain the question of the leg on which the improvised products are stored in working order now. The very name "knife" in Russian came out by itself from the word leg. The reason is that the cutter was kept in the top of the boot, so that it would not get lost, would not interfere, and could not cut through something by negligence. And even today, many specialists, for example, divers and people who are engaged in cutting livestock, lay this type of device in a sheath suspended from the bootleg.

The requirements for a knife include, first of all, reliability, which consists in strength and sharpness. The most reliable cutting tool is a one-piece extension of the handle and blade, which extend each other. Many people use folding devices, which, under increased loads, especially for fracture, lose strength at the most crucial moments.

Construction fixtures with retractable cutting parts do not differ much from each other in many characteristics. Almost the only and their main difference is the mechanism that fixes the sharpened metal. The locking mechanism in this product is a clamping wheel, which is tightened after the cutting element has been extended to the required length. The unreliability of such devices lies in the plastic handle, the age of which is not long. It does not make sense to change it, and it is often just a pity to throw out products. It is a typical reason that such products are not recommended for basic work, only for sharpening a marking pencil, opening bags of bulk material, or for cutting mosaic sheets.

The cost of the products discussed above varies in different price categories. For example, a product with spare cutting elements and a three-component handle from the manufacturer GROSS can be purchased at a price of 540 rubles. A construction aid from Stenley Interlock will cost 256 rubles, and from Haupa - from 702 rubles. The cost of a replaceable cutting element ranges from 15 to 99 rubles per piece from manufacturers such as Sparta, GROSS.

A knife, the handle of which is a continuation of the blade, from the manufacturer Fiskars in a retail network can cost 360 rubles. At the same time, it will be a more reliable assistant than devices with movable devices. We will talk about reliability, the material used in the manufacture and much more in the next section.

Raw materials used to make knives

In the auxiliary product, the main thing is the sharpness of the cutting element, and this indicator depends on the quality of the raw materials used in large-scale production. The cutting component must be neither soft (bend in all directions) nor brittle (break when cut).

Many manufacturing companies make blades from valve heat-resistant steel. More often, saw blades are used for production, which are intended for metal cutting work. The average size of such blanks: 25-30 centimeters and a web thickness of approximately 2 mm. The finished product has approximate dimensions: the length of the sharpened part is approximately 15 cm; handle length - 10-12 centimeters.

The handles can have a wide variety of configurations, but the material is used with fairly high strength rates. For example, there are holders made of ebonite, textolite, most often they use wood blanks from birch or mountain ash. You can make a mold for casting the handle with your own hands, in which you place the blade blank and fill it with a mixture of powder used by electricians when sealing the reconnecting sleeves of a high-voltage cable.

As a rule, the holder consists of two plates, which are drilled only after appropriate marking. In this case, both halves should be superimposed on each other, and the reconnecting holes should run through the holes in the metal blank of the future cutting element. The diameter of the holes in all components must be the same.

The fastening of the three components is carried out using rivets, which are made of aluminum wire. Such wire is used by electricians in the process of laying overhead lines. It is also permissible to use copper wire, as long as its diameter is slightly smaller than the drilled holes in the handle plates and the workpiece metal, so that it freely enters them. In this case, the wire should not hang freely.

On the one hand, the wire is riveted, and a kind of "fungus" is obtained. Then the length of the segment is measured, somewhat larger than the thickness of the cutter handle, cut off and threaded into the holes, placed on the anvil and the second side is riveted. It is desirable to process the resulting rivets on both sides with sandpaper. Rivets can oxidize during prolonged interaction, for example, with water or other aggressive media.

If the metal plate has a single hole, then one rivet is made at the end of the handle. The second rivet can be replaced by a copper or brass shell from a pipe of the required diameter. The shell is flattened at the junction of the handle and the metal blank, in accordance with the initial shaping of the handle, carefully processed and polished. To prevent displacement of the shell, on the side of the metal plate, as an addition, a strip of the same type of metal is placed across.

We touched on the issue of the scabbard in which it is worn, and the manual device is stored. It is safer to use a case that should be placed in one specific place so as not to lose or search for a hand tool for a long time at the most necessary moment. Homemade cases made of metal, leather or wood are often used. The only condition for storing the device in a case concerns the contact of the cutting metal part with the internal surfaces. That is, the knife should be clamped exclusively in the side surfaces.

We add that it is desirable to sharpen the active metal part on a special machine tool. When processing on your own, try to start the process with a rough impact, for example, on a sharpener with a coarse grit with an abrasive wheel. Next, move on to circles with a finer grit. Finishing should be done with sandpaper, canvas straps, and then leather. Observe the sharpening angle, which should be about 15 degrees (+- an error of a few degrees). Of course, the sharpness of the tool will be tested by practice, but do not forget to cool the blade with water during the sharpening process, especially when using a sharpener.