Spiked dovetail connection. "Dovetail" mount, connection. Cleaning the cutouts between the spikes

Of the various types of connections between two removable parts in mechanics and the wood industry, the dovetail mount is the strongest and most reliable. In working with wood, this type of joints, or locks, is used in all forms of production.

Ways to use dovetail attachment:

1. furniture manufacture;
2. connection of workpieces to each other;
3. connection of bars;
4. fastening the timber during the construction of houses.

With large-scale production, the structure of this lock is quickly and successfully performed by a dovetail cutter. At home, in the absence of milling equipment, it is not difficult to make a dovetail with your own hands. At the same time, the ability to make this structure with high quality is considered a high-class craftsmanship.

This article provides detailed description the manufacturing process, with a step-by-step listing of all the techniques, so that a master of any level would understand how to make a dovetail.

Preparation for work

Before starting, the following materials and tools should be prepared.

Materials

Name	Type and dimensions, mm	amount
Wooden blocks - blanks	40x40x500	2
Wood glue	—	1

Tools

List of tools used in the manufacture:

• a circular saw;
• belt sander;
• manual eccentric sander;
• miter saw;
• band-saw;
• manual frezer;
• workbench with clamping vice;
• chisel straight;
• manual jigsaw;
• finger mill 10 mm;
• clamp;
• joiner's square;
• ruler:
• pencil;
• file;
• sandpaper, grain 100.

Description of the manufacturing process

The design of this carpentry lock is a tight fit of two parts. At the end of one bar, a V-shaped projection is made, resembling a dovetail (where the name comes from). On the second bar, a cut is made in the shape of this protrusion. The thickness of this spike can be the full width and the floor of the tree. The thorn and the cut are made at an angle of 10-12 degrees.

This article describes the process of making this joinery joint into a wood floor. The type of product that should be the result is shown in the figure.

1. Through circular saw cut 2 identical bars.
2. They are processed on a grinding machine.
3. The ends of the bars are cut with a miter saw.

Advice! In the event that multiple connections are required, it is recommended that a dovetail pattern be made from a thin, dense material, which increases productivity. The described example shows a single production of this structure.

When the ledge is ready, a slot must be made for it on the second workpiece. To do this, markup is made on the second workpiece, using the first in the form of a template. It is necessary to make the markings as accurate as possible, since any backlash between the parts is not allowed. The design will be unreliable. For this reason, the upper lines are drawn with a cutting knife. The middle is marked with a pencil.

Next, you have to choose in the bar, according to the marks made with a jigsaw, a slot for a thorn. This can be done in two ways. In the first case, the slot is selected using a chisel, cutters, a file and sandpaper. Extreme care must be taken here, since it is necessary to maintain a perfectly flat surface for joining and gluing parts.

If a manual router is available, it is much easier to make a dovetail with a router, since it is much easier to get the perfect result in this case than by hand.

In order to complete the dovetail connection, and to ensure a tight and reliable connection of the parts, on workpiece 2, using a chisel, they carefully cut the edges of the sides, periodically trying on the spike and trying to insert it into the slot. The spike should fit tightly, but without undue effort.

Important! After the spike has entered the intended place, the parts should be disconnected. In order to do this, it is necessary to clamp the workpiece 2 in a vice, and using a wooden mallet, carefully knock out a bar with a spike from the slot, as shown in the figure. If you try to do this by hand, you might break the thorn.

Finally, wood glue is applied to the surface of both parts to be joined. The parts are connected to each other and pressed tightly with a clamp.

After a certain time required for the glue to harden, the part is cleaned of glue residues using a chisel. A manual eccentric sander brings the surface of the finished structure to an ideal state. The construction is ready.

Conclusion

Practice shows that the dovetail connection is the most common reliable wooden locks in the carpentry industry. When correct manufacture and reliable bonding, it is able to withstand heavy loads of tearing, shock and vibration. It has been used since construction wooden houses... In the old days, this castle, common in carpentry and carpentry, called the dovetail, was called a frying pan.

Currently, this type of wooden lock is widespread throughout all countries, in all types of wooden joints.

Video

The detachable fastening of parts by the "dovetail" method is performed by installing a trapezoidal spike, cut out at the edges of another element, into a groove arranged 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 proceeds to perform preparatory operations, in the process of which the bed and the 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, the connection types can be made from light non-ferrous metals and plastic. The surface of the product is processed with a profile cutter with finishing with a scraper or a polishing disc.

Before making a "dovetail" with your own hands, you should create a drawing, the dimensions of which must withstand the permissible operating loads. When making a cut, it is necessary to correctly select the angle of inclination of the sides of the trapezoid, the standard value of which is 45 0, 55 0 and 60 0. The connection according to the selected method is applied in the system:

1. small arms canopy;
2. metalworking machine;
3. optical device;
4. "In the paw" and "skvorodem" in wooden housing construction.

TO positive properties technology includes high structural strength. Application of the method allows you to fasten elements without nails, screws, screws and chops.

Application of the method with wood

The wood spike and the fastening groove must have the same shape and be connected in a tight sealed knot. The dovetail joint, the drawing of which is intended for different products, helps to form a T-shaped and angular fastening of boards, beams or logs without overlaps in the places where the internal partitions are installed. The technology for assembling wooden structures allows you to use for interior partitions construction material smaller diameter. If necessary, protection from wind and drafts, the corner joints of the structure of the capital structure are sealed with jute fibers.

A classic example of the use of connecting elements is the drawer of a furniture set. The electrical carpentry equipment used in the construction of the tongue-and-groove system for the hand router allows the weaving of the tenon elements using the natural resistance of the joint to the force applied to the face of the product during extension.

The connection, the drawing of which is drawn up for each item individually, can be performed in different ways.

Most of the craftsmen working in the furniture industry and housebuilding prefer the method of through-joint joints because of the decorativeness of the repeating pattern. The preparation of the elements is carried out on a milling machine with a special device.

Marking connecting pins

The preparation of the material for connecting the thorn groove with your own hands according to the template is carried out after marking the "tails" with a thickness gauge, pencil or marker on the sides and edges of the part with sockets or partitions. The size and number of elements depends on the type of material, the width of the board and the way the spikes are located. To give decorative look connection lines, the spikes must have the same dimensions, be 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 distance of 6 mm from the edges. The rest of the board must be divided into an even number of spikes, measure 3 mm on each side of the marks, draw a marking line perpendicular to the end. Using a stencil or a bead, draw the slope of the dovetail studs.

Cutting trapezoidal spikes

To form the connecting elements, the box blank is installed in a vice so that one side of the spikes is vertical. On the lateral edge of each tenon, cuts are made that do not reach the line of the shoulders, the workpiece is repositioned, and other lateral edges are processed in the same way. After that, the part is fixed horizontally, the lateral deviation is cut off at the level of the shoulders. Excess wood between the thorns must be removed with an openwork saw.

Marking and cutting out the landing nest

For accurate marking of the seat, the workpiece is placed on a carpenter's table in a vice with a vertical position, the end of the board is rubbed with chalk to obtain an imprint on the part with already cut thorns. With help special device the edges, the line of the side shoulders are aligned in the shape of the spikes and the end face of the blanks with sockets.

After finishing preparatory work you can start forming grooves at the corners of the workpiece next to the shoulder line in accordance with the spike markings. The cut, for which the spike groove cutter is used for the hand 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, cleaned with a chisel or chisel with a beveled edge. The movement of the tool should be directed from the edges to the center.

Assembling the joints

Almost all types of wood, plywood, and plastic are used for the production of products, the parts of which are connected by the dovetail method. A feature of the method is non-separable technology with the use of fasteners (wood glue). Accuracy check and fitting of parts is carried out after:

1. preliminary "dry" assembly of the final product;
2. removing excess material;
3. stripping or sanding tight spots.

The adhesive is applied to the contacting sides of two wood pieces. For a tight connection of parts of the structure, a hammer and a wooden gasket are used to protect the product from accidental damage.

After tapping the junction along the entire line, it is necessary to remove excess glue, the product is sent to dry, followed by stripping with a jointer in the direction from the edge to the middle.

Shape and solution of the angle of cut

Standard corners of the bond should not be sharp or obtuse. The steep slope of the milling cut encourages short grain formation in the corner. Insufficient slope of the groove reduces the strength of the connection of the elements. To solve the problem, experts recommend using bevel markings, templates or stencils. For hardwood, it is necessary to choose the optimal cutting slope, which should be 1/8; for soft wood, the slope is milled by 1/6.

Decorative connection of elements

A neatly executed groove "dovetail" can serve as an additional decoration for household and office furniture. Furniture design options allow you to emphasize the beauty of wood and appreciate the skill of a specialist. The selected type of assembly of the product corresponds to the indicators of the standard proportions of the structure.

The peculiarity of the "dovetail" is the possibility of cutting a log or a bar into a half-tree in the form of a trapezoid when corner mount details. IN wooden construction often used the method of joining the bars in the "root spike" method, when two elements are spliced \u200b\u200bwith a rectangular spike and a groove of the same shape. Cutting of parts for connection is carried out by a cutter according to drawings, diagrams and dimensions.

The reliability and aesthetics of complex wood structures largely depend on the right choice way to connect it component parts... This is especially true for frame products, supporting structures, where safety parameters come to the fore.

Quality connection wooden parts - the guarantee of durability, the basis for an attractive appearance of the product, an indicator of the skill and professionalism of a carpenter and joiner.

Choice of connection type

In general, there are a huge number of types of joints of wooden blanks, so you can only talk about some of them, the most common.

One of the most simple ways build up a wooden part (timber, log, board), increase its width is the end connection. There are several options for its implementation. A simple and functional half-thickness (half-tree) method is often used. Depending on the expected load on the part, the cut can be flat or oblique. In some cases, the joint is strengthened with curly cutouts - locks. This type of connection prevents stretching, twisting, bending. So the beam is spliced \u200b\u200btogether for the purpose of lengthening.

Creation of volumetric frames or wooden frames requires reliable connections at various angles. In this case, it is rational to use a thorn-groove or thorn-eye connection. The nodes at the junction of the parts withstand the load of displacement, bending and compression. If the structure requires high tensile strength, the cutouts are trapezoidal.

Additional connections of frame products, which impart rigidity to the structure, are realized using T-shaped or cruciform connections. The main stress at the joints is compression, displacement and rupture. IN special cases the structure is additionally reinforced with metal corners, screws or nails.

It is convenient to use a special box groove to connect the boards to each other in box structures at right angles. As the name implies, this method is often used to create three-dimensional structures, including furniture boxes. A well-made box joint looks monolithic, has an attractive appearance and can withstand impressive loads. When creating wooden furniture, they often use a connection on dowels, dowels and dominoes (when the groove has an oblong shape, as opposed to a round dowel).

Spike connection (spike-groove)

The simplest and one of the most reliable is the tongue-and-groove connection. It is widely used in carpentry... In a similar way, wooden parts of window frames are assembled into a single whole, a variety of cabinet furniture parts, plywood sheets are made. The essence of this method is that a spike is made at the end of one part to be connected, which is inserted into the groove of the other part and fixed in it.

For work, it is convenient to use a special lamellar cutter; hand tool... You will need:

• hand-held butt saw with fine teeth;
• electric or hand drill;
• several chisels of different widths;
• sandpaper;
• measuring tool, square and pencil.

First, the blanks are marked. The parameters of the tongue and groove depend on the parameters of the wooden parts and the configuration of the product, however, it is worth considering a few general recommendations.

Important! The thickness of the spike should be about a third of the thickness of the part, the width should be 70-80% of the width, the length should be equal to the thickness of the workpiece being joined.

The groove parameters must also meet these criteria. In any case, it is important to ensure that the dimensions of the tongue and groove match. The parts should be connected easily, without pressure, but not fall out under their own weight. There should be no backlash, cracks and distortion.

The groove is cut first, this sequence is due to the fact that the tenon is much easier to fit under the groove than vice versa. With the help of a saw, cuts are made, excess wood is removed with a drill, the bottom of the groove and the walls are leveled with chisels.

In most cases, only wood glue is enough to fix the parts; screws or nails will help to ensure maximum strength.

Half-tree connection

Quite often in carpentry they use different options half-wood joints (simple or straight lock). This type of assembly wooden structures characterized by ease of manufacture and high reliability... There are the following varieties:

• cross connection;
• half a tree - dovetail;
• gusset;
• on a mustache;
• splicing in half a tree.

The first two methods are used to connect parts that intersect at right angles. Particularly popular is the dovetail, in which the shape of the neckline is a trapezoid and the sides are not at right angles. The slot of the lock expands slightly from the end, providing a more secure fit. It should be noted that a tenon joint can also be called a dovetail if the tenons are cut in the form of trapezoids.

The second and third modes form a complete corner. Splicing is used if necessary to increase the length of the workpiece.

How to make a cross connection

One of the simplest is the cross connection. It is distinguished by its simplicity of manufacture, even a novice carpenter can master its wisdom. The work is done in the following order:

• markup is done. The parts to be joined are superimposed on each other. Use a ruler to draw a cut line. A thickness gauge is used to mark the thickness;
• the first part is clamped in a vice. Hand saw, carefully, along the lines, a cut is made to the mark left by the thickness gauge. The workpiece turns. The second cut is made;
• the workpiece is removed from the vice. Using a sharp chisel and a wooden mallet, part of the wood is removed between the cuts;
• the second part is processed;
• the planes are leveled with sandpaper or an abrasive bar.

Now you can join the wooden pieces. The connection must be tight, without backlash and gaps. If the product is one-piece, the joints are coated with wood glue, the structure is additionally reinforced with screws.

Forming mustache corners

One of better ways creating corners of various volumetric products is a mustache joint. It allows you to create a monolithic structure, hide the fibers of the end, thereby providing an attractive look. This method is suitable for a wide variety of products, but is most often used for the manufacture of frames and cabinet furniture parts.

To create a connection in each of the wooden parts, cuts are made at an angle equal to half the angle at which the blanks meet. Most often, this angle is straight, therefore, the cuts are performed at 45 degrees, however, the angle can vary widely. The work is performed according to the following algorithm.

First, the details are marked. It is important not to forget that the markings are carried out on the long side, otherwise you may not guess with the dimensions.

On the edges to be connected, draw a line at the required angle. With a combined square, the markings are transferred to each side of the workpiece. Then a cut is made, for which it is better to use an electric miter saw, but you can also work with a hand tool. When working with a hacksaw, it is important to control the angle of the cut; it will be useful to use a bar as a guide.

The finished parts are applied to each other, checking the accuracy of the fit. Irregularities will have to be smoothed out with a hand plane, to bring the angle with the help of a sandpaper. Joiner's glue is applied to both surfaces, and the product is fixed with clamps. Additional strength can be achieved with studs. When working with a hammer, it is important to control the force of the impact so that the workpieces do not move.

Particularly critical connections are reinforced with bars that are glued into the inner corner. A joint that will not be visible can be additionally reinforced with a metal square.

As a result of well-done work, you will get a perfect seam. If a small gap has formed, then it can be hidden by straightening the adjacent wood fibers using a smooth cylindrical surface. For this, the shaft of an ordinary screwdriver is suitable.

Thorn in the eye

Corner and T-shaped (example: T-shaped connection of a window frame) intersections are conveniently performed using the tongue-and-groove method. In this case, the eyelet is made at the end of the vertical part, the cuts for the thorn are made in its horizontal component.

Work begins with marking the eyelet. The thickness of the workpiece is divided by three. With a thin hacksaw, cuts are made to a depth equal to the width of another workpiece. With the help of chisels, excess wood is removed, the walls of the eyelet are leveled with sandpaper.

The second workpiece is marked out. The width of the tenon should be equal to the width of the first blank, the thickness equal to the thickness of the tenon. The cuts are made with a hand hacksaw, the depth and angle of inclination are carefully controlled. The excess is removed with a chisel.

The final finishing in thickness is carried out with sandpaper. The parts should be connected with light effort and not fall apart under their own weight.

Thorn in the socket

More complex connection is the way to spike into a socket. It requires more skill, but is much more reliable and durable. The scope of use is the same as in the previous case, namely, T-joints. The difference between this method is that the spike is made at the end of the vertical part, a socket is cut out in the body of the horizontal part.

This is one of the most common furniture connections. Distinguish between connection with a through thorn and a blind. The difference is that in the first case, a through socket is cut, in the second, a slot is made to a certain depth.

Features of Japanese joinery

Japanese craftsmen have reached unprecedented heights of carpentry. Using traditional techniques, combining different types connections, they create precise and reliable joints without the use of nails and other fasteners. The joining of various wooden parts is carried out solely due to the frictional force.

The reliability of these connections is based on an accurate cut. Perfectly matched lock lines on both mating parts create a connection with impeccable precision. Complex configurations of locks require a lot of experience, knowledge and ability to own the tool, but if you wish, you can learn all this.

Pulling boards together

Quality wood is expensive, buy good board with the necessary parameters is not always possible, and not always necessary. To make, for example, a tabletop, it is not at all necessary to look for a board the width of a table, having the skills of carpentry, you can create the perfect wooden canvas with the required parameters.

There are many options for rallying. A board with a spike and a groove, the so-called lining, is widespread. It allows you to create even wooden surfaces large area. A simplified version of it is often used - a board with a quarter joint.

Rallying on a smooth puffer (butt)

The easiest way that does not require additional elements. The side edges of the boards are planted, it is better to do this in pairs, clamping both adjacent boards in a vice and simultaneously processing them. Such processing will create a precise surface on which the unevenness of one board will be compensated by the unevenness of the other. Both boards are coated with glue and fixed until it hardens completely.

Consolidation of load-bearing elements

Extend (build up) the board that is part supporting structure in several ways. The simplest and most reliable is a half-wood connection with subsequent overlay on the junction of the reinforcing strips. Non-critical areas can be reinforced with plywood.

The same method is used for joining the boards at different angles. Precisely made cuts of the articulated parts make it possible to do without reinforcing linings, it is enough to fix the boards at the junction with screws.

Cutting without residue means that the laid logs will form an even corner, their ends will not protrude beyond the structure, a separate variety of it is a warm corner. The cut with the remainder, in turn, means that an interlacing of protruding ends will form at the corners of the building. The second method is more costly in terms of the amount of material, but the building retains heat better and is more stable.

There are various ways to connect wood parts, the ability to determine the optimal one for a particular type of work will significantly diversify the range of products that a master can make. The right way will provide an attractive appearance the product and guarantees the reliability of the volumetric design.

How to make a spike box connection with a hand tool.
Multi-stud box connections are classic carpentry technologies. They are still used today in the production of quality furniture. Of course, in our time, simpler and faster methods of assembling boxes are more often used. I myself usually collect boxes on self-tapping screws, but I will write about this in another article. Here I propose to remember how it was done from time immemorial with a hand tool.

Actually, the questions of making spikes by hand sometimes arise if you do not have special tools and devices at hand. And it makes no sense to buy an expensive machine for a one-time job. True, you need to understand in advance, manual work requires care and accuracy.

From the tools you will need a hacksaw-reward, a set of chisels, a mallet. For marking, a pencil and a metal ruler. The reward differs from a conventional hacksaw not only by a small tooth, but also by a special “back” pad on the upper edge of the saw. This pad provides additional rigidity to the web.

Spikes can be made self-gripping, i.e. Dovetail or straight. It is better to start with straight lines, the dovetail can be used when some experience appears. The details of the box in the photo are made of MDF, but this is not important, wood blanks are processed in the same way.

1. Let's start by marking the ends of the parts. Drawer slats 100 mm wide. divided into five equal parts. Divide them into 20/20 mm squares. , then we will match the ends of the parts and shade the squares through one with a pencil.

That is, a clean square should be located opposite the shaded one. When making the thorns, we need to remove the painted areas.

2. For the convenience of work, the part must be clamped vertically. If you do not have a carpentry workbench, then fix the part with two clamps to the work table. To do this, clamp a wooden block on the edge of the table with one clamp, and pull the part to the block with the other.

3. We cut out the thorns along the markings, and note that you need to cut not along the line, but so that the marking lines remain to the side of the saw. If the cuts are made exactly along the line, then the spikes will be loose and the assembly of the box will become a problem. We'll have to glue veneer or chips into the gaps, in general, hemorrhoids and poor-quality work. We are cutting out the areas we have filled with a pencil, so the saw should be inside the shaded sector. We make cuts to the marking depth, in this case 20 mm.

4. With a chisel or a cutter, we select the segments between the cuts.

We take out the part from the clamp and place it flat on the table. With a chisel we align the shoulders between the thorns. In order not to spoil the table, it is better to put a planed board or a piece of plywood under the workpiece. You might need a hammer, look.

5. When all the spikes are sawn and finished, we carry out the initial assembly. If, during assembly, the spikes do not fit into place, it's okay, you need to adjust the parts using a chisel or a cutter (knife). For a high-quality assembly, fractions of a millimeter are important, therefore, for an accurate fit, it is better to work on the spikes with a file or a large sandpaper on a long bar.

Once I had to make not only boxes on thorns, but also knit wooden window frames using a hand tool. There, the principles of work are the same, the spikes and lugs were first cut out according to the markings with a saw - a reward, and then he cut out the excess in the lugs with a chisel.

If you need to make a lot of boxes with a spike connection, then it is better to think about purchasing an electric tool. Such spikes can be made with a hand router installed in the "table", or on a small stationary circular with a variable saw height. For both options, you will need to make a device for accurate cuts. But it seems to me that making such a device is no more difficult than manually preparing parts for several boxes.

Wooden and veneered furniture, as well as other, assembled from separate structural elements, made of solid wood, unfortunately, cannot serve indefinitely. And this is understandable. In addition to natural aging and various "diseases" of wood, there are loose adhesive joints, traces of careless storage, unskilled repairs, restoration and others. Most often, furniture with a weakened strength of structural joints comes into restoration. individual elements, in particular spike joints.

1.1. Strengthening the nest-thorn, dovetail joints

It should be noted that over the past two centuries, furniture has been assembled using various tenon joints. Most often, a socket-thorn connection or similar hidden connections was used, in which wooden pins (rods) were used. Such connections hold the frame of many tables, armchairs, chairs, sofas and other furniture items. This position remains unchanged in the practice of restoration of structural elements made of solid wood to this day.

The socket-tenon connection is a rectangular version of the structural assembly of furniture and has two main methods of connection. The first is when the nest is stepped and the tenon is one end of the wood element is cut and adjusted to fit into the nest cut in the other element. In another method, the tenon is flush with one side of the planar strapping of a furniture piece, for example a table drawer.

Figure: 1. Dovetail joint

The dovetail joint (Fig. 1) is a complicated version of the socket-tenon joint. The thorns should fit snugly into the swallow-tailed nests, which increase the strength of the connection; they separate in only one direction.

"Dovetail", as well as "nest-thorn", are used to connect two wooden flat elements, converging at right angles, for example drawers tables, cabinets and other products.

Figure: 2. Reinforcement of the dovetail joint with inserts

Figure: 3. Strengthening the socket-tenon connection with inserts

In the case of a rod (initial) connection, one structural element (part) of furniture, with a nail glued into the socket, is inserted into the socket on the second element with pre-applied carpentry glue.

The strengthening of the dovetail and nest-tenon spike joints are shown in Fig. 2 and 3 respectively.

IN wooden chairs, armchairs, sofas, there are many connections, more than in other types of furniture. The joints discussed above must withstand significant loads, although sooner or later in any furniture they are weakened or completely destroyed. One loose connection leads to an increase in the load on good connections, so the weakened one must be strengthened - and the sooner the better.

In cases where disassembly of furniture is undesirable, and spike joints it is strongly weakened, the adhesive joints are strengthened by injecting liquid fresh carpentry glue with a medical syringe and kept until the glue is completely dry. The place of gluing is fixed with clamps.

If it is necessary to provide increased strength of the joints, then the structure of the furniture frame is strengthened with additional details: cut plates from ordinary multilayer birch plywood, glued with hot carpentry glue inside the frame and fixed screws; wooden bosses, also glued in inner corners tsarovy belt of chairs, armchairs, tables; wooden pins, which are driven with an interference fit and glue into the holes drilled in the spike joints.

During restoration work, when the spike joints are disassembled, the spikes are cleaned of old glue. To remove the glue from the surface of the thorn, use a knife, cycle, coarse sandpaper. It is necessary to hold the knife almost perpendicular to the wood of the thorn, applying force on the blade so as to remove the dried glue without pressing the knife into the wood. The nest is cleaned of old glue with a chisel by scraping, while it expands slightly to create space for an expanded tenon due to an additional spacer from a thin veneer plate. This will provide increased bond strength when re-gluing. In addition, if there is a gap in the socket-thorn joint, then a wedge is sometimes added for tight joining, and in some cases, for greater fastening, a beveled key is driven into the edge of the joint.

If the spike has a crack, then it is sawn through with a tenon saw and a low-cut wedge is inserted into the cut.

If the spike breaks, it is replaced with a new one. To do this, in place of the old thorn with a chisel, make a nest with a depth of 2-3 cm, into which a new thorn is glued.

After eliminating all defects on the parts and checking the fit of the spikes and sockets, the spike joints are again glued with wood glue. To do this, glue is applied to the spikes, dowels and gaskets, as well as to the sockets. After assembly, by placing the spike in the socket, tighten the spike joints with a clamping device and hold them until the glue is completely dry.

1.2. Reinforcement of tongue and groove joints

The tongue-and-groove connection (fig. 4) is used when the joining places of structural elements are rectangular, for example, two folding boards.

Figure: 4. Joint in "tongue and groove"

This connection is weakened as a result of the simultaneous shrinkage of the tongue of the furniture element and the thickness of the tongue. The thickness of the ridge is restored on both sides with thin veneer spacers. If the crest has cracks or is broken off, then it is cut off with a plane. In its place, a recess is made, that is, a tongue of the same width and depth as that of the board to be attached. The boards are rallied to a thorn. The plug-in spike is glued into the groove, and the direction of its fibers should be perpendicular to the direction of the fibers of the parts to be joined. The dowel can be made of plain birch plywood with a minimum thickness of 5 mm, if the ribs of the tongue to be joined are of sufficient thickness.

1.3. Strengthening the connections on the dowel

Round pins are widely used to connect individual elements (Fig. 5). So, for example, a dowel is used to connect two broken parts of a chair or chair leg. The nests for the dowel are drilled with a drill required diameter... The head is not necessarily made of the same material as the furniture. The best pins are made from beech, which is less brittle than oak. The dowel should penetrate deeply (up to 5-6 cm) into the parts to be joined.

Figure: 5. Connection on the dowel

1.4. Strengthening the joints for a "smooth joint"

The connection of the boards to a smooth joint (Fig. 6), weakened as a result of warping of the boards and shrinkage, is reinforced with transverse dowels of a trapezoidal or rectangular cross section.

Figure: 6. Joint for "smooth fugue"

They are inserted into the grooves made on the inner (non-front) side of the part. The dimensions of the keyway for thin boards must be at least half of their thickness. Glue the boards along the edges and glue the dowels at the same time. To do this, after applying glue, the rallying boards are placed face down on a dense and even backing board, the dowels are inserted and placed under a press. At the same time, using a clamp, the boards are squeezed from the edges. This eliminates minor warpage of the overall surface.

Strengthening the joints on a smooth joint can be done with dovetail inserts (fig. 7) - this is a traditional method.

Figure: 7. Reinforcements with a dovetail spike

"Dovetail", sometimes called "butterflies" by restorers, is an insert in the form of double thorns. After the parts of the boards are connected, grooves are cut in the tree about a third of its thickness in the shape of the insert, into which they must fit tightly. Inserts are made of the same type of wood as the exhibit, or of durable wood (oak, beech); their fibers should be perpendicular to the direction of the fibers of the edges to be joined. The dovetail should be wide enough in the middle (center). Due to its shape, this insert provides a strong connection, but some restorers consider it insufficient.

1.5. Strengthening the connections on the "mustache"

Restorers quite often meet with joints of furniture elements on the "mustache" (Fig. 8), which consist in the imposition of one element on another with an inclined cut. The parts to be joined should, if possible, have the maximum contact surface, then the reliability of gluing will be the greatest. The glued place is strengthened with dowels or plug-in spikes.

Figure: 8. Strengthening the connections on the "mustache"

1.6. Strengthening the joints with "breadcrumbs"

This method of strengthening the elements of the furniture structure and their connections is used when the furniture cannot be dismantled. Strengthening can be done with connecting straps of any shape (Fig. 9).

To seal the crack from the inside and prevent it from spreading, you can use a lining to secure the joint vertically and horizontally. The plates are made of wood of the same species as the exhibit itself. When sticking them on a crack, it is necessary that the fibers of the linings be perpendicular to the fibers of the parts to be joined. Frequently glued cracks are not straight, then it is preferable to make not one patch, but several smaller sizes next to each other. After covering with good wood glue, if possible, they are tightened with screws. The advantage of this reinforcement of the joints is that the linings can be removed as needed.

One of the types of overlays is "crackers", which strengthen the connections of the tsarg with the leg. Some restorers object to the use of "rusks", considering them irrational. They prefer to dismantle furniture, redo the drawer side with a new internal connection. This violates the principle of maximum preservation of the original. In addition, it is sometimes harmful to remove the upholstery and then dismantle the exhibit. "Crackers" compensate for the "fatigue" of the drawer side wood, caused by numerous renewed upholstery. "Crackers" are especially useful when the bars of the seat drawer are bent and have longitudinal cracks.

Crackers are made from soft, well-glued wood species (linden, poplar). Their height should be equal to the height of the sidebar. From the inside, they are given a concave line, because this shape facilitates the upholstery and the final fastening at the corners of the side bar and leg connection. "Crackers" are installed after the legs are fixed. If they fit well and are glued, then there is little need to screw them on. But some restorers, nevertheless, during gluing press the "crackers" with clamps, and after gluing they screw in the screws. It is unacceptable to use nails.

Figure: 9. Strengthening the joints with "breadcrumbs"