What is a timber connection? dovetail?
Very often, novice developers ask what is dovetail and how to apply it in practice? We are happy to explain all the most important aspects of this type of timber connection, i.e. connecting beams into a dovetail.
In fact beam joining can be produced different ways, but the most effective and elegant will be the so-called “dovetail”. Its design is capable of rigidly preventing the penetration of direct air flows into the premises. In terms of strength, such a connection is considered the most reliable, since it is very rigid, it is impossible to break it even with a high deformation load on the building. Dovetail log houses can withstand strong earthquake(tested in practice).
A properly cut (sawing) joint is very tight. True, wood natural material, and it tends to be subject to natural thermal expansion. During the drying process, timber can repeatedly absorb moisture and release it back into the atmosphere. Naturally, the percentage of humidity gradually decreases and eventually returns to the norm of natural shrinkage. To increase the density of connections, in place beam joining use interventional insulation from flax, jute or tow.
The dovetail connection has been tested over the years and has a quality standard.
By using a dovetail as a timber connection, you will already partially solve the problem of heat loss through the walls of a timber house, because you will get a high-quality warm corner. The regulations for the use of this connection are established by GOST 30974 - 2002 “Corner connections of wooden cobblestones and log low-rise buildings. Classification, designs, sizes." This fact is significant and convincing, since we are still accustomed to trusting government agencies in the field of quality control and operational safety.
Application options for joining beams in a dovetail
Even despite some difficulty in performing the work, do connection of beams into dovetail no problem. Here you need to make a dovetail template and mark the cut points using it. The template must be made in advance from a sheet of tin or plastic. It is more convenient to cut with a chainsaw with a short bar.
Let's list the options for joining timber that dovetail can be used:
1. Dovetail is effective when joining timber along the length.
Dovetail jointing of timber along the length
Dovetail
2. Dovetail is often used to join timber when joining interior wall to the outside.
3. In the corners of a house made of timber, a half-dovetail joint is used (photos are clickable).
Corner beam connection
Corner dovetail beam connection
IN carpentry there are quite a large number of connecting parts to each other. One of them is the dovetail. This type of connection can be seen on drawers, chairs and other structures. It is one of the reliable connections. The grooves are made in such a way that if you try to break the connection, they will rest against each other. In order to make a dovetail with your own hands, you will need a minimum of tools and a little experience in carpentry.
Connection types
Depending on the task at hand, dovetailing can be performed in various ways:
- Corner connections.
- Separating.
- Through.
- Decorative.
- Bevel connection.
- Through connection with rebate.
All types of connections have their own strengths and weak sides, but, one way or another, they form reliable connection two parts. To work you will need the following tools:
With these tools, you can easily make the connection. If it is possible to use a hand router, then the need for the listed tools disappears.
Through connection type
This type of connection is widely used in the manufacture of both housing and upholstered furniture. It is also called “box”.
To begin with, the workpiece must be processed with a plane and excess wood removed. The next step will be marking the nests. Everything here is individual and depends on the width of the board, as well as on the tasks assigned. It is necessary to draw lines across the workpiece at a distance of 6 mm from both edges. Then you need to divide the distance between them into an even amount, set aside 3 mm on each side and draw lines across the end.
Now you need to mark the slope of the spikes with a small marker. The excess that remains should be marked to avoid confusion in the future.
After marking, you can begin cutting out the tenons. This can be done using a jigsaw or regular saw with small teeth. For convenience, the workpiece can be clamped in a vice. Using a saw, you need to cut out one edge on each side of the tenon. You should cut it out carefully, otherwise there will be small gaps that will damage it in the future. appearance. The same must be done with the other side spikes.
The side waste should be cut off from the shoulder line, and excess wood between the tenons can be easily removed with an openwork saw. Residue on both sides can be removed with a chisel or beveled chisel.
The cutting of the tenons is completed, and you can begin marking and cutting out the nests. Using the same vice, clamp the workpiece. The part with spikes must be attached to the workpiece and carefully mark the shape of the spikes.
After marking, carefully cut out the nests along the previously drawn lines. The cut from the main part should be made in such a way that it does not reach the marking line slightly. Carefully cut off part of the waste with an openwork saw. In order for the two parts to fit tightly together, it is necessary to clean the corners with a cutter.
When the two connections are ready, you can start joining them. It must be remembered that the connection is assembled only once. Before gluing the parts, you need to make sure that they fit tightly together. If there are any irregularities, they must be removed before gluing.
If everything fits tightly, then the following manipulations should be performed:
- Two blanks need to be coated with glue, then connected to each other.
- Tapping wooden hammer, fit two parts. Excess glue must be removed. Otherwise, after drying, the appearance will be ruined.
- After drying, the gluing area is sanded on both sides.
- Then check the angle, which should be 1/8 for hardwood and 1/6 for softwood. If the angle is too large, short fiber will be formed, which may affect the strength of the connection.
All these points also apply to other connection modifications. And they should be performed in the same sequence.
Decorative variety
This type of connection is used in places where beauty is needed. This connection also emphasizes the art of the master. In order to give decorative look thin partitions are used. At the end of the workpiece, carefully apply a line for marking the shoulder pads. Continue the marking line to the end and mark the excess. When cutting tenons, waste must be removed in the same way as for through joints. Stripping must be done from the ends to the middle.
Before fixing, the workpiece must be coated with chalk for a more rigid fixation. At the end you need to mark the distance between the small partitions, then continue all the lines of the tenons to the line of the shoulder pads, you must not forget about removing the excess. Most of the waste can be removed using a tenon cutter, and the shoulder pads are best trimmed with an openwork saw. To cut out small partitions, you need to press the workpiece firmly.
Using slow movements along the grain, make a cross cut near the shoulder line. The operations should be repeated. After these manipulations, apply glue and fasten both surfaces together.
Bevel connection
In some cases it is necessary to combine two types of connection. The depth of the cut in such cases depends on the profile and chamfer.
Using a thicknesser, mark the line of the shoulder pads on both sides. Apply a bevel line on the top edge. At the bottom of the workpiece, you need to mark a certain depth for the chamfer. Draw a line across the end and up to the line of the shoulder pads. From the first mark, put another line 6 mm long. Do the same with the bottom edge. Mark on the resulting marks required quantity thorns Mark the remaining excess.
Cut the tenons with a jigsaw and fit with a fine sandpaper. In this option, the excess is temporarily left. Apply a line of shoulder pads on both sides. Make a small mark on the top edge of the bevel line. Mark the tenon sockets on the workpiece and mark the bevel on the lower part. After finishing the manipulations, remove all excess.
Seam connection
Quite often used in the manufacture of tables and chairs. At the bottom of the box, a special selection is made, which is called a “fold,” and the bottom of the box is inserted into it. During such a connection, gaps may appear in the corners, which can be eliminated by moving the shoulder pad.
The markup is slightly different from previous versions. On the sides you need to draw a line along which you can determine the depth of the rebate. The inner side is marked using the same thickness planer parameters. Below the rebate depth, mark 6 mm, and place the next mark from the opposite edge. On the resulting marks, mark the desired location of the spikes. Draw a line across the chamfered edge, but it must completely correspond to the marked fold.
Marking the nests is done in exactly the same way as in the previous versions, using a ready-made blank with spikes and drawing supplies.
Another variation of this connection is the bevel connection. In it, the entire connection is hidden by a bevel, which adds beauty to the product. Before assembling, the workpieces must be adjusted to the required size. It should be remembered that the nests must be made first, and then the thorns. The marking of the tenons is carried out identically to the other option, but with one caveat: between the thicknesser line and outer corner Using a special scriber and chalk, you should mark a bevel on each of the edges.
Make sure that there is no more than 6 mm from the shoulder line to the overlap. At the end between the drawn lines you need to mark the width and position of the sockets. For convenience, you can make ready stencil made of plywood, press it against the side walls and continue the marking line, after which all excess is removed. Before gluing two joints, you need to test them. If there are defects, remove them with a chisel and sandpaper.
Inclined docking
Mainly used for large parts. In terms of difficulty, it ranks first. In order to make a tenon and groove with your own hands in this type of connection, it will take much more time. The complexity of manufacturing is associated with the peculiarity of the connection, in which all the edges are located at a certain angle. Before marking, the boards must be adjusted to the same width. A drawing for a dovetail connection will greatly facilitate the task.
The drawing should begin with a lateral projection, and it is also necessary to indicate the thickness and dimensions. As for the vertical projection, it can be drawn, just like the lateral one. Use the same method to design the side view. The figure shows a drawing of a dovetail, the dimensions of which are a specific standard.
The next step is to cut the piece to length and width. Place a small tool on point X and move this angle to inner side. Saw off the remaining ends. Place another small piece on the U corner and place it on the edges. Now we need guide lines, which can be obtained by connecting the marks on the edge.
Carefully trim off the end bevel. On front side Parts with spikes should be marked. You need to measure the size of the material using the beveled ends. Apply a small tool to point X and mark a line along the edge of the parts. Place 6mm notches on the top and bottom edges. The position of the studs can be calculated from these marks.
The slope of the tenons must be marked on the inclined end of the parts. For convenience, you can use a small spoon. Using a stencil and a square, mark the spikes. Mark the remaining excess. When cutting out tenons, you need to rely on the previously marked corners, after which you can draw and cut out the nests using the finished workpiece.
All excess is carefully removed at the end of the work. If for some reason the slope is not satisfactory, then it can be trimmed after gluing or cleaned with a grinder. If you have to hammer out the joints with a mallet, you need to place a piece of a block, otherwise marks may remain.
Manual frezer
If you constantly have to study similar compounds and produce them in large quantities, then manual method won't do. Exist stationary machines and manual milling machines, which, using a special cutter, can make a certain number of tenons or “tails” in one pass. To save even more time, you can make templates. To create tenons and tails, you must have a tenon-groove cutter for hand router.
Before milling, the workpiece should be placed vertically for convenience. Before this, you need to mark the number of tails. When milling, waste will be generated, which can be easily removed with a router.
You can purchase templates at the market or in a store, with the help of which things will go even faster. You need to attach and fix the device to the top of the workpiece. Then set the required cutting depth on the router. After milling, all connections are smooth and require virtually no adjustment.
If carpentry work is to be done and a strong and reliable connection of two parts is necessary, then the best option there will be a dovetail. If you have a hand router, even a beginner in carpentry can make tenons and tails. In addition, after assembly, such a connection looks aesthetically pleasing.
Detachable fastening of parts using the dovetail method is carried out by installing a trapezoidal tenon, cut into the edges of the other element, into a groove located on one side of the workpiece. The type of connection of parts is used in many structures that require the creation of a rigid one-piece frame: small arms, furniture production, mechanical engineering, wooden capital construction.
After the drawing is drawn up, the dimensions of the dovetail are selected individually. The master begins to carry out preparatory operations, during which the bed and slide take part. The material used in the process of solving the problem with loaded nodes can be steel, cast iron, bronze. In other cases, connection types can be made from light non-ferrous metals and plastics. The surface of the product is processed with a profile cutter and finished with a scraper or polishing disc.
Before you make a dovetail with your own hands, you should create a drawing, the dimensions of which must withstand permissible operating loads. When making a cut, it is necessary to correctly select the angle of inclination of the sides of the trapezoid, standard value which is 45 0, 55 0 and 60 0. The connection according to the selected method is used in the system:
- small arms canopy;
- metalworking machine;
- optical device;
- “in the paw” and “squawk” in wooden housing construction.
The positive properties of the technology include high structural strength. The use of the method allows you to fasten elements without nails, screws, self-tapping screws and chops.
Application of the method with wood
The wooden tenon and fastening groove must have an identical shape and be connected into a tight, sealed unit. Dovetail connection, the drawing of which is intended for different products, helps to form T-shaped and corner fastening of boards, beams or logs without overlaps at installation sites internal partitions. The technology for assembling wooden structures makes it possible to use interior partitions construction material smaller diameter. If protection from wind and drafts is necessary, the corner joints of the structure of a capital structure are sealed with jute fibers.
A classic example of the use of connecting elements is drawer furniture set. Electrical carpentry equipment, used when constructing a tongue-and-groove system for a manual router, allows you to intertwine tenon elements using the natural resistance of the joint to the force applied to the front part of the product during extension.
The connection, the drawing of which is drawn up for each item individually, can be made in different ways.
Most craftsmen working in furniture production and house construction prefer the method of through-joining joints because of the decorative nature of the repeating pattern. The elements are prepared on a milling machine using a special device.
Marking of connecting tenons
Preparing the material for connecting the tenon and groove with your own hands according to the template is carried out after marking the “tails” with a thicknesser, pencil or marker along the sides and edges of the part with nests or partitions. The dimensions and number of elements depend on the type of material, the width of the board and the method of placing the tenons. To give a decorative appearance to the connection line, the spikes must have same sizes, located at the same distance from each other.
Before starting work on the machine, the material is equipped with markings across the workpiece with a deviation of 6 mm from the edges. The remaining part of the board must be divided into an even number of tenons, measure 3 mm on each side of the marks, and draw a marking line perpendicular to the end. Using a stencil or chalkboard, draw the contours of the slope of the tenons for the dovetail joints.
Cutting trapezoidal tenons
To form the connecting elements, the box blank is placed in a vice so that one side of the tenons is vertical. On the side face of each tenon, cuts are made that do not reach the shoulder line, the workpiece is reinstalled, and other side faces are processed in a similar way. After this, the part is fixed horizontally, the side waste is cut off at the level of the shoulder pads. Excess wood between the tenons must be removed with an openwork saw.
Marking and sawing out the landing nest
To accurately mark the seat, the workpiece is placed on carpenter's table in a vice in a vertical position, the end of the board is rubbed with chalk to obtain an imprint on parts with already cut tenons. With help special device the edges, the line of the side shoulder pads in the shape of the tenons and the end of the workpieces with sockets are aligned.
After finishing preparatory work you can begin to form grooves at the corners of the workpiece next to the shoulder line in accordance with the tenon markings. The cut, for which a tenon and groove cutter is used for a manual router, should be made in the waste part of the board so that the groove is parallel to the marking line. Excess wood between the partitions of the nest is removed with an openwork saw and cleaned with a chisel or chisel with a beveled edge. The movement of the tool should be directed from the edges to the center.
Assembly of connecting joints
For the production of products whose parts are connected using the dovetail method, almost all types of wood, plywood, and plastic are used. A special feature of the method is its non-separable technology using fastening agents (wood glue). Accuracy check and fitting of parts is carried out after:
- preliminary “dry” assembly of the final product;
- removing excess material;
- stripping or sanding tight areas.
The adhesive is applied to the contacting sides of two pieces of wood. To tightly connect the parts of the structure, use a hammer and wood spacer, providing protection of the product from accidental damage.
After tapping the joint along the entire line, it is necessary to remove excess glue, the product is sent for drying, followed by cleaning with a jointer in the direction from the edge to the middle.
Shape and angle of cut
Standard bonding angles should not be sharp or obtuse. Big slope The milling cut promotes the formation of short fibers in the corner part. Insufficient groove inclination reduces the strength of the connection between the elements. To solve the problem, experts recommend using bevel markings, templates or stencils. For hardwood wood you need to choose optimal slope cut, which should be 1/8; for soft wood, slope milling is done by 1/6.
Decorative connection of elements
A carefully executed grooved dovetail can serve as an additional decoration for household and office furniture. Design options for furniture designs allow you to highlight the beauty of wood and appreciate the skill of a specialist. The selected type of product assembly corresponds to the standard design proportions.
A feature of the “dovetail” is the possibility of cutting a log or beam into half a tree in the shape of a trapezoid when corner mount details. IN wood construction The method of connecting beams using the “root tenon” method is often used, when two elements are joined with a rectangular tenon and a groove of a similar shape. Cutting out parts for connection is carried out using a milling cutter according to drawings, diagrams and dimensions.
Modern carpentry experts consider fastening logs without leaving dovetails as a practical and reliable option. corner connection. The T-shaped installation of beams is almost similar to the fastening with a main tenon, only the tenon has the shape of a trapezoid, which ensures ultra-reliable joining at the corners of the house. A properly cut dovetail gives the entire structure of the house additional strength, durability, and prevents deformations natural to wood.
Heritage of wooden architecture
Wood is a traditional building material in Rus'. Built in harsh climatic conditions, huts and towers made of larch, cedar, and pine were highly durable, warm, dry, and cozy. Various cutting techniques were used: in a corner, in a clapboard, in a bowl; these techniques involved slightly moving the ends of the logs beyond the corners of the house, which protected them from freezing even in the most severe frosts. The Siberians considered this technique to be preferable, but there were other methods of construction. These techniques are without residue, that is, without bringing the log to the surface of the wall:
- into the paw, the logs were cut together at the ends, one log seemed to be inserted into the paw of the other;
- in the ohryakka, while recesses were made in the log in the upper and lower parts;
- in a dovetail, when a tenon was cut out in the idea of a trapezoid in one log and a nest for it in another.
These are just the basic techniques of a log house, along with many other crown joints for which craftsmen in Rus' were famous. Installation was carried out without fasteners or dowels and wooden pins were used to additionally fasten the corners together. Household buildings were sometimes erected using the pole method, when vertical logs were tied together.
Important! Compounds without residue, including dovetail, were used for cold outbuildings. Modern methods insulation allows the use of dovetail fastenings, which is attractive because it makes the building frame especially stable and strong.
The main trick of fastening a dovetail is that a trapezoidal tenon wedges the ends of the logs, which are pressed down by the weight of the entire structure. Without any fasteners, they do not separate or move apart.
Advantages and disadvantages of fastening
The dovetail fastening technology is complex. Not everyone can cut out the tenons of a trapezoid; skills in working with wood and using carpentry tools are required. But everything would be possible if desired.
Dovetail as a method of connecting crowns has the following advantages:
- saving wood, this method is considered low-waste;
- extra meters usable area, fastening without residue increases the length of the wall by 10-12%;
- any possibility exterior finishing, thanks to smooth corners;
- high reliability of the locking connection;
- savings on fastening materials;
- additional protection against swelling of logs, the angle of the connection prevents water from entering the lock;
- nice appearance.
The main argument in favor of this method of fastening may be century-old houses and buildings, which are not difficult to find in the Russian outback.
The dovetail method is, in fact, a redesigned claw fastening, also called oblique claw, emphasizing its traditionality.
Important! Dovetail refers to cold joints of logs in the corners, so prepare insulation immediately. Pay attention to acrylic sealants suitable for sealing and insulation. Choose environmentally friendly insulation materials that are easy to install, jute fabric, for example.
However, there are also disadvantages of this method. These include:
- cracking of wood under the influence of temperature changes, however, this disadvantage is inherent in all types of joints;
- the possibility of fungus and mold occurring at joints; appropriate wood treatment and high-quality waterproofing are required;
- the difficulty of cutting out trapezoid tenons.
It is really difficult to cut out a tenon without making mistakes. It is required to maintain a length of 40mm per dowel, patience is required. Craftsmen advise preparing a prototype of a trapezoid tenon, which can be used to make log blanks for subsequent laying. The prototype is applied to a log, outlined, then cutouts are made using a hammer and chisel. You won’t be able to use the saw right away; you could ruin the material.
Important! Invite professional carpenters, at least to look at their work, then move on to self-construction walls with dovetail fastening.
Features of the technology
The dovetail fastening technology complies with GOST 30974-2002. It is used mainly for connecting low-rise buildings made of timber, less often from rounded logs. The connection has the following types:
- using a key that is driven into trapezoidal grooves;
- tenon fastening;
- fastening in the groove.
The most common type of mounting is in the groove. It is used for both external walls, and internal. This best method when assembling a structure from living, undried wood with a diameter of 260-320 mm. If you use logs of a smaller diameter, the tenon may break off; for larger diameter beams, other problems associated with greater weight are typical; over time, the tenons may be squeezed out to the surface.
The logs are prepared before laying. A tenon is cut out on one, and a notch is cut on the other for the first log with a tenon. They start with the first crown, or as it is also called the frame. It is laid on a layer of waterproofing, the horizontal is adjusted using wedges, since the surface of the foundation is not always perfectly flat.
The installation of the first and second crown, as well as all subsequent ones, occurs in pairs; first, two logs opposite each other are laid, then two perpendicular ones. If the connection turns out to be loose, the material is removed and the cut is adjusted at the corners.
Important! Before you start building a house or other serious structure, test the technology on something small, a doghouse, for example. After the technology has been mastered, feel free to begin the main construction.
And to make sure the technology is reliable, look at other uses in the firearms industry, such as furniture assembly.
For a long time, inventors have been inspired to make discoveries not even by the principle of their action, but by their appearance alone. The snail inspired the development of a pump with the same shape as its shell. It is quite possible that round celestial bodies became the prototype of the wheel. Even the dovetail found a use. Its characteristic bifurcation with an angular cutout is recognizable; it has become the prototype of many technical and theoretical solutions. Some of them are discussed below.
How to make a “non-pull-out” bracket?
For wall mounts Often there is a need for a bracket that is subject to multidirectional forces. If a support is simply hammered into the wall like a nail, it is possible that under the influence of loads it will come out of its place and fall out. To prevent this from happening, they often use a simple, but original solution. In a bracket (for example, a piece of plate or metal corner) do lengthwise cut, and the resulting ends are unbent in opposite directions. All that remains is to cut a hole in the wall and embed it in it using mortar design, which received the name “dovetail” for its bifurcation. The fastening is very secure, it is difficult to pull out such a bracket. This method is used especially successfully for walls made of soft calcareous stone, for which other methods or chops) are ineffective.
Construction and wooden architecture
In Russia, and not only, in Lately Ecological housing construction has become widespread. Log houses, huts, traditional wooden houses They meet safety requirements, they are environmentally friendly, they retain heat well and, finally, they can simply be very beautiful. The logs that make up the walls can be joined at the corners in several ways, but most often builders use the so-called “dovetail.” The fastening is based on a beveled groove, which prevents the component parts of the structure from leaving their places under the influence external forces. The advantage of this method is that it does not require fastening hardware(staples or nails - “crutches”), and therefore the cost is reduced, and if necessary, you can move the structure by disassembling it in the reverse order of assembly, removing each beam one by one. Dovetail is a method of erecting towers “without a single nail.” It was mastered perfectly by ancient Russian architects, who created true architectural masterpieces. Some of them are presented in the museum under open air in Kizhi, where they were transported from all over the country in disassembled form due to the fact that they can withstand an almost unlimited number of disassembly and assembly cycles.
Furniture and accessories
Trends in furniture design change cyclically, like any other fashion. One thing remains unchanged: quality is always highly valued. "Aerobatics" of a carpenter of the highest qualifications(this is also called a cabinetmaker) is considered to be a manner of work in which the articulations of the constituent parts of a table, chair or cabinet are not hidden, but are, as it were, exposed. Here, they say, is how the bureau drawer is made, no fiberboard or plastic, wood is everywhere, and the accuracy of the fit can be visually assessed. To prevent the walls from creeping apart during transportation and simple operation, the good old “dovetail” is often used. The fastening looks quite organic in expensive furniture, especially when the shades of the rocks contrast. General principle the same as in the construction of wooden log houses, however, grooves are made using special equipment in a structurally integral element, a board.
Carpentry equipment
The dovetail machine is in no way similar to bird plumage. It looks like a kind of combination of a metal comb and wooden base. But with its help, a qualified furniture maker will make the incoming teeth and counter slots with high precision in such a way that they connect at right angles and with minimal gaps. It is difficult, if not impossible, to achieve this effect manually. At its core, this machine is a milling machine; to work with it, special cutting attachments (mills) are used, which form tenons and corresponding grooves in the wood with uniform frequency and high quality.
How did the shipbuilders do it?
Requirements for rigidity, strength and reliability have always been placed on watercraft. The impacts of ocean and sea waves can shake the strongest hull of a ship, especially if it is made of wood, as in ancient times. The dovetail type of connection of parts was very often used, for obvious reasons, by shipbuilders. It is worth mentioning that this industry has always been characterized by the most Hi-tech. For cutting large protrusions and recesses in solid wood, there is even a special dovetail saw, which itself is completely different from the forked silhouette of a bird. Against, cutting part of this instrument is straight and level. The hacksaw saw got its name from its purpose; it is convenient for cutting grooves and teeth with inclined edges. It is used in combination with other carpentry tools, the most important of which are the chisel and chisel. A hacksaw of this type is today used only in limited areas of production, for example, in eco-style or luxury housing. Real carpentry masters, as a rule, have this tool.
Walls of the ancient Kremlin
Yes, yes, the Moscow Kremlin, and many other medieval ones, have had the same “dovetail” on their walls for many centuries. It is enough to carefully examine any of the battlements crowning the fence of the heart of Russia to notice the bifurcation of its specific outline. It is difficult to say how unique this form is; similar decisions were made in other European fortresses of that time. For what? It is possible that the architects were motivated by practical considerations, and the forked recess served as a support for arquebuses or cannons, although the gaps between the teeth could be sufficient for these purposes. Or maybe this was a peculiar architectural fashion. However, similar merlons (teeth) decorate the walls of the Kremlin in Tula, as well as the fortresses of many European cities (Pisa, Florence, Pistoia, Lucca, etc.). It is unknown who was the first to come up with the idea of decorating fortifications with “swallow tails”. Most likely, the fashion for them was brought to Russia by architects invited from Italy (for example, Pietro Solari took part in the construction of the Moscow Kremlin at the turn of the fifteenth and sixteenth centuries).
Trailer
Trailers are used to transport vehicles and other equipment that cannot be transported under their own power (from broken-down cars to tanks). They are also called “dovetail”. The trailer has characteristic retractable or elevating structural elements, sometimes equipped with guide sides designed for the passage of wheels of loaded machines. During transportation, these “tails” rise. It’s clear why this name stuck: retractable or raised ramps are two parts, similar to the forked plumage of a swallow.
Tripod use
The dovetail movable joint method is indispensable for tripods. This connection can be found on various optical tripods for a wide variety of purposes (from telescopes to movie cameras) and other devices whose design requires high-precision translational mobility. Among its advantages are minimization of backlash, ease of movement along a given line, and the ability to install a measuring scale that can be equipped with a bearing bar. “Dovetail” is in this case a fixed guide with side cutouts (in cross section angular), and a carriage moving along it, equipped with a counterpart of the appropriate shape. Great importance It also has the ability to unify similar tripods. The distance between the side parts may differ, the main thing is that the angle of the edges coincides. For pairing different devices with one base, a dovetail adapter is used, the design of which has adjusting threaded elements that allow you to change the base of the supporting part.
Every hunter wants...
Every shooter knows that the essence of aiming is to align three points: the slot of the bar, the top of the front sight and the place where you want to hit. Only if the distance, wind and lead are taken into account correctly (if the object of the hunt is mobile) can one hope for a hit. The design of weapons, and therefore sights, may differ. There are semicircular, rectangular and those called “dovetail” slots. A sight of this type allows an experienced shooter with certain skills to quickly calculate the distance to the target.
And the method of mounting it is often the same as on tripods of optical instruments, and what it is called is not difficult to guess. In general, it is almost difficult to imagine modern weapons without a dovetail.
"Tails" in other areas of knowledge
The term turned out to be so figurative and successful that it is used to designate almost any diverging (or converging) figure. Mathematicians call graphs of intersections of complex curved surfaces “dovetails”; mechanics call them a special type of jagged kinematic pairs, physics - dependencies of ambiguous parameters. Even economists believe that charts of exchange rates or investment expectations sometimes resemble dovetails. This happens in cases where the spread of data decreases or increases over time. In general, this is the name for everything that diverges in two, or, on the contrary, is joined together from two parts.