Methods for attaching boards to each other. Methods and methods for joining wooden parts

Timber products such as beams, boards or bars are usually produced in a specific size, but often during construction a material that has a greater length, width or thickness may be required. For this reason, to achieve the required size, several types of connections are used using notches made with specialized equipment or manually using markings.

Width connections

After fastening boards with a small width, a shield with the dimensions required for production is obtained. There are several methods for docking:

1)Docking on a smooth fugue;

In this method of joining, each board or lath is called a plot, and the formed seam is called a fugue. Jointing can be considered high-quality only when there are no gaps between the joints of the edges of adjacent boards.

2)Rail fastening;
Grooves are selected along the edges of the plot and slats are inserted into them, fastening the boards together. The thickness of the slats and the width of the groove itself cannot exceed 1/3 of the thickness of the timber used

3) Quarter fastening;

in joined plots, quarters are selected completely along the entire length. With this method, quarters cannot exceed 50% of the thickness of the plot itself.

4) Tongue and groove type docking (rectangular and triangular);
This type of joining provides for the presence of a groove on one edge of the plot and a ridge on the opposite edge, the shape of which can be either rectangular or triangular. However, the latter is used infrequently, due to its lower strength level. This kind of joining is quite in demand and is often used in the manufacture of parquet. Lack of fastening - lower economy due to the use of more boards

5) Fastening type " dovetail»;
this type of joining is somewhat similar to the previous version, but only the crest here has a trapezoidal shape, similar to the tail of swallows. Hence the name of the fastening method.

Connecting boards into panels: a - into a smooth reveal, b - into a quarter, c - into a batten, d - into a groove and a rectangular ridge, e - into a groove and a triangular ridge, f - into a dovetail.

Also, in the production of wood panels, dowels, a comb with glued into the end strip and tips in the groove are often used. The slats for gluing can be rectangular or triangular. When using dowels, it is better to prefer a dovetail groove. All this is necessary for the production of high-quality wood panels.

Boards: a - with keys, 6 - with a tip in the groove and tongue, c - with a glued strip in the end, d - with a glued triangular strip, d - with a glued triangular strip.

Length connection

The most popular methods of joining along the length are: close, tongue-and-groove type, miter-type fastening, jagged type of adhesive fastening, quarter-joint, as well as rail fastening. The gear type joining is most actively used, due to its extremely high level of strength.

Connection of bars along the length: a - end-to-end, b - in a groove and tongue, c - on a miter, d, e - on a toothed adhesive joint, f - in a quarter, g - on a rail.

Also, boards can be joined using the splicing method, when segments of timber are joined together in length. This is done in several ways. For example, in half a tree or with an oblique type of cut, an oblique and straight lock, close to each other, as well as a tension lock like direct type, and oblique. When splicing using the half-tree method, the required length must be 2-2.5 times the thickness of the bar. To increase the level of reliability, dowels are used. For example, a similar option can be observed when building cottages from timber.

When using an oblique type cut with cutting the ends, the size should be equal to 2.5-3 times the thickness of the bar. It is also secured with dowels.

Fastening using an oblique or straight type lock is used in those structures where there is a tensile force. A direct type rim lock is placed directly on the support itself, and an oblique type lock can be placed at the support.

If you have decided to use an oblique cut with cutting the ends, then the fastening must be 2.5-3 times the thickness of the bar. In such situations, dowels can also be used.

When fastening using an oblique or straight type tension lock, it is achieved high level strength. But at the same time, such a joining is difficult to manufacture, and the wedges become somewhat weakened as the wood dries out. For these reasons similar method fastenings are not suitable for structures bearing high loads.

Splicing back-to-back involves moving both ends of the beam onto a support and then fastening it together with staples.

Splicing: a - half-tree, b - oblique cut, c - straight patch lock, d - oblique patch lock, e - straight tension lock, f - oblique tension lock, g - end-to-end.

The fastening of logs or beams can be observed during the construction of walls frame houses, in the upper or lower part of the harness. The key types of fastenings are: half-wood, corner frying pan, tenon type and half-foot.

Joining half a tree - direct cutting or cutting off 50% of the thickness at the edges of the bars, as well as their subsequent fastening at right angles.

The half-foot joint is formed by cutting at the edges of the beams inclined planes, resulting in a tight connection of the beams. The amount of slope must be determined using a special formula.

Notching using a corner frying pan is extremely similar to notching using the half-tree method, but differs from it in that with this type of fastening, one of the bars loses a little in width.

Connection of beams at an angle: a - half-tree, b - half-foot, c - tenon, d - angular.

Height connection

Cross-shaped fastening of bars is often observed during the construction of bridge structures. With this option, you can use joining in half a tree, in thirds and quarters, and also in notching only one of the bars.

Cross-shaped connection of beams: a - half a tree, b - a third of a tree, c - a quarter of a tree, d - with a notch of one beam.

The method of increasing boards or bars in height is called fastening materials in height, which is very actively used in the construction of pillars or masts.

Extension is divided into the following types:

Close with a hidden type spike.
Closely with a through-type comb.
Half-wood with bolted fastening.
Half-wood with fastening on clamps.
Half-wood with fastening with a steel strip.
An oblique cut-off with fastening on clamps.
Close with overlays.
Fastening with bolts.

The length of the joints themselves, as a rule, is equal to 2/3 of the thickness of the joined bars or 2/3 of the diameter of the logs.

Connection of logs when building up: a - end-to-end with a hidden tenon, b - end-to-end with a through ridge, c - half-tree with fastening with bolts, d - half-tree with fastening with strip steel, d - half-tree with fastening with clamps, f - oblique cut with fastening with clamps, g - end-to-end with linings and fastening with bolts.

Tenon connection

When fastening beams with tenons, a direct tenon is cut on one of them, and an eye or a socket is made on the other. Knitting beams using the tenon method is actively used in the production of joinery products such as doors, windows or transoms. Each fastening is based on glue. It is allowed to use not only one spike, but also several. How larger number spikes are planned to be made, the correspondingly larger the gluing area will be.

This type of joining is divided into: corner end type, corner middle type and corner box type.

When corner fastening of the end type, unclosed through tenons (no more than three), tenons with darkness of the through and non-through type, as well as an insert dowel are used. A mid-type corner connection is quite common on doors. For corner fastenings of the middle and end type, you can additionally use screws, nails or bolts.

Angular middle connections to the tenon: a - non-through type US-1, b through US-2, c - through double US-3, d - non-through in the groove and tongue US-4, e - non-through in the groove US-5, f - non-through on round dowels US-6.

That's all the key information about existing types connections. This does not include connections made with nails, screws or bolts. Pure wood and a little glue. 🙂

Models, core boxes and other parts of model kits are usually made not from a whole piece of wood, but from individual pieces. The main types of connections between parts of wood blanks in model production are bonding, knitting and partially splicing.

Joining is the connection of boards or bars in width and thickness, in which the grain fibers of the wood are arranged in parallel. Rallying is used mainly to obtain shields and massive blanks. When joining whole workpieces from individual parts, glue, nails, screws, dowels are used, and joining of split workpieces is done on tires, wedges, etc. The most common method of joining is joining by butt gluing with layers or edges (Fig. 92, a, b) . The narrower the boards (plots) being welded together, the less warping there will be.

When consolidating, the location of the annual layers of wood is taken into account. Blanks made by butting together with seams are quite strong and are almost not deformed compared to blanks joined by edges. For the most critical work, bonding with layers is used according to the method shown in Fig. 92, v. The planed board is sawn into bars of a certain width and joined together in layers into a whole workpiece, but this method of joining is much more expensive than the methods shown in Fig. 92, a, b.

The boards for split models are joined so that the growth rings are directed with the convex side towards the split plane (Fig. 92, d), and for split core boxes of small sizes - vice versa (Fig. 92, e).

Rice. 92. Examples of rallying:

a - butt with seams, b - butt with edges, c - butt with sheets of sawn boards (pieces), d - for a detachable model, d - for a detachable core box, f - in a rebate, g - in a tongue and groove, h - on round tenons, and - into the tongue and groove onto the rail

Joining can be done by connecting boards and bars into a fold (Fig. 92, e) and into a tongue (Fig. 92, g), but these methods of joining do not provide a tight seam. They are used in the manufacture of products without gluing, operating under conditions of significant changes in humidity.

When making wide and long boards, in order to increase their strength, at least two round (Fig. 92, h) or rectangular wooden spikes with glue are placed at the edges of the boards. The diameter or thickness of each of them should be equal to 1/3 of the thickness of the shield, and the height should be double the thickness. It is advisable to set the distance between them up to 500 mm in a checkerboard pattern. The marking of the sockets for the spikes is done accurately, the spikes are fitted tightly to the sockets, the depth of which should be 3-5 mm greater than the length of the spikes.

Racking into a tongue and groove onto a lath (Fig. 92, i) is one of the simple and convenient ways to connect boards with edges. The glued-on lath ensures strength as well as precision of the boards being joined, since the edges can be well aligned to each other. This method of joining is more economical than joining in the fold and in the tongue, since part of the board is not wasted on the lath, which is usually made from waste.

To increase strength and prevent transverse warping, the panels are fastened with dowels and lugs. A dowel is a wooden block of trapezoidal shape in cross section, which is fitted to the surface of the panel.

In the manufacture of model kits, overhead keys are widely used (Fig. 93,a). The dowels are tightly fitted to the plane of the shield and glued. When the adhesive layer has dried, screw in the screws. This method is simple, reliable and the most common.

Gluing the shield with dowels into a groove is shown in Fig. 93, b in two versions. According to the first option, key 1 is driven in the form of a wedge into a through groove cut across the shield (may not be through), having a depth equal to 1/4 of the thickness of the shield and tapering along the length towards one end at an angle of 2-3°. The groove is sawed through with a sand file, the cut layer is first chopped off with a chisel, and then cleaned with a zenzubel or primer. According to the second option, key 2 is made with shoulders. Its protruding part has the same width along its entire length. These dowels are driven into the groove of the shield with glue. This method is used for more critical parts of the model and core boxes.

An example of fastening a shield with a tip mounted with a tongue on a ridge made at the end of the shield is shown in Fig. 93, v. To make the fastening stronger, the tip is attached to the end of the shield with one, sometimes two hidden screws.

In Fig. 93, d shows a method of fastening the shield with tip 3 into a plate using glue and screws. On the other side, the shield is fastened with a strip 4, which is driven with glue into a groove made in the end of the shield. Thick panels are fastened in this way. The thickness of the rail 4 should be approximately 0.4-0.5 of the thickness of the shield. It is convenient to make the groove for the rack on a milling machine.

There is also a way to fasten boxes with a frame into a frame. Framing is considered the best measure to protect the shield from warping. IN carpentry production that part of the shield that is located inside the frame is called a panel, and the whole shield with a frame is called paneled (Fig. 93, e). To strengthen the shield in the frame, tongues or folds are made on the inner edges of the frame bars, and the shield has ridges or folds, respectively.

Due to the limited size of wood, creating building structures of large spans or heights from it is impossible without connecting individual elements. Connections of wooden elements to increase the cross-section of the structure are called rallying, and to increase their longitudinal length - splicing, at an angle and attached to the supports by anchoring.

Increasing the length of workpieces is called splicing. Increasing the cross-section of blanks is called joining. Connections of wooden structures are classified according to various criteria. For example, by the type of operation of the element and the operation of the connection itself (connections on tensile connections, connections on flexible connections).

According to the nature of the work, all main connections are divided into:

without special connections (front rests, notches);
with connections working in compression (block keys);
with bending connections (bolts, rods, nails, screws, plates);
with tensile connections (bolts, screws, clamps);
with shear-chip bonds (adhesive joints).

According to the nature of the joints in wooden structures, they are divided into flexible and rigid. Pliable ones are made without the use of adhesives. Deformations in them are formed as a result of leaks.

It is customary to distinguish three groups of connections of wooden structures:

Contact connections (without the use of working mechanical connections: notches and other “butt” connections)
Connections using mechanical connections (dowels: bolted, nailed; keyed, connections on washers, dowel plates, etc.)
Adhesive and combined type joints

Connection requirements

1. Reliability. In particular, it is recommended to minimize unfavorable (unreliable) types of wood work in joints (wood chipping, crushing across the grain, stretching across the grain). The so-called principle of fragmentation is closely related to the concept of reliability: “the smaller the connections and the more of them, the higher the reliability of the connection.” In other words, ten bolts of small diameter are preferable to one bolt with the same metal costs, since in the first case the wood works mainly in compression (the “reliable” type of wood work), and in the second case - in shear (the “unreliable” type of wood work)

2. Strength. In particular, the desire for equal strength with the main part of the structure, for the absence of weakening (holes) in the section.

3. Reduced labor intensity in the manufacture and installation of structures (manufacturability)

4. Deformability. For example, in contact joints the magnitude of the ultimate bearing strain is limited

The work of wood in joints. Types of wood work that involve bending across and at an angle to the grain, as well as chipping, are considered unfavorable. It is these types of wood work that accompany the work of connections and they are most often the direct or indirect cause of structural failure.

Crumpling. The work of wood in compression across and at an angle to the fibers is characterized by increased deformability and low strength. The force-deformation diagram when wood is crushed across fibers reflects the effect of flattening the tubular cells of wood. There are three types of crushing:

n collapse over the entire surface (R cm = 1.8 MPa, the most unfavorable type of collapse)
n crushing along part of the length
n crushing on part of the surface (under the washers) (R cm = 4 MPa)

The increase in strength in the latter case is explained by the reinforcing influence of wood fibers surrounding the crushing area.

Basic empirical dependencies for crushing.

Dependence of resistance on the angle between the direction of force and the direction of wood fibers

R cm,a = R cm,0 / (1 + (R cm,0 /R cm,90 - 1) sin 3 a

Dependence of resistance on the length of the crushing area

R cm,L = R cm (1 + 8 / (L cm + 1.2);[cm]

Chipping. The work of wood on chipping (shear) is characterized by low strength and brittle nature of destruction. In its “pure” form, chipping practically does not occur. Usually this type of stress state is combined with others (tension and compression across the fibers).

There are two types of chipping: one-sided chipping and two-sided chipping. In the first case, the strength is lower, since the degree of uneven stress distribution is higher. In the calculations, a uniform distribution of stresses along the length of the shear area is conventionally assumed. Therefore, the concept of “average shear strength” is introduced

R sk,av = R sk,av / (1+ bL/e)

The formula reflects the physical essence of the shearing phenomenon: coefficient b takes into account the type of shearing, and the L/e ratio takes into account the influence of normal stresses accompanying shearing. R sk, avg— resistance to shearing with uniform distribution of tangential stresses.

The dependence of the chipping resistance on the angle between the direction of the force and the direction of the wood fibers has the form:

R sk,a = R sk,0 / (1 + (R sk,0 /R sk,90 - 1) sin 3 a

Purpose of connections	In factory-manufactured structures	In structures manufactured using lightweight mechanization means.
Purpose of connections	from dried lumber	from beams and boards	from local roundwood
*Rally*	On waterproof glue	On oak or birch plates Derevyagin; on nails and thick dowels made of round steel, made of plastic	On pads, bolts, brackets
*Building up*
In a compressed joint	Frontal support
At a stretched joint	Serrated joint with waterproof glue	Wooden plates and gaskets on round steel dowels, bolts, nails	Wooden plates on round steel dowels, bolted
At a stretched joint	Overlays with cleestal washers	Overlays with washers on blind dowels and screws	Steel plates with washers on blind pins and capercaillie
*Nodal connections*
Compressed rods	Frontal and three-frontal emphasis	Frontal cut; frontal and three-frontal emphasis
Stretched rods	With steel ties or clamps through linings and gaskets on glue or dowels and bolts	With steel ties or clamps through linings and gaskets on nails or dowels and bolts	Steel ties or clamps through linings on dowels and bolts; cross profile brackets
Rods that perceive alternating forces	Center bolt through cleestal washers	Dowels, cross profile pins, nails	Dowels, cross profile pins
Rods that perceive alternating forces	Center bolt through cleestal washers	With a center bolt, through claw washers, washers on blind dowels, screws, cross profile pins or on nails	With a center bolt through washers on blind dowels, capercaillies or on cross-profile pins

Main types of connections (when rallying)

1. Connections to cuttings working without special work connections. The connections are non-expansion; only auxiliary cross braces are required (outdated type of bonding)


Connection diagram for notches
The main area of application of notches are joint connections in block and log trusses, including in the support joints of the compressed upper chord to the stretched lower chord. Elements of wooden structures connected by a notch (d.k.) must be fastened with auxiliary connections - bolts, clamps, staples, etc., which should be calculated mainly for installation loads

2. Connections on dowels working mainly for compression(c), similar to the compressed truss braces (c). The thrust Q sp is perceived by working transverse connections (p) - bolts, clamps, etc., working on stretching similar to stretched truss posts (r)


Keyed connection diagram

3. Connections to dowels working mainly for bend(and), similar to the racks (and) of a braceless truss. The connections are non-thrust, only auxiliary cross braces are required

4. Connections on glue, working mainly on shift(τ), similarly weld seam in metal beams. The cross-link is usually provided by the adhesive seam itself

Width connections

When joining narrow boards, boards of the required size are obtained.
There are several ways to connect.

1)Connection to a smooth fugue;
With this joining method, each strip or board is called a plot, and the seam that is formed as a result of the connection is called a fugue. The quality of jointing is indicated by the absence of gaps between the joints of the edges of adjacent plots.

2)Rail connection;
Grooves are selected along the edges of the plots and inserted into their slats, which fasten the plots together. The thickness of the slats and the width of the groove should not exceed 1/3 of the thickness of the board.

3) Quarter connection;
In plots that are fastened, quarters are selected along the entire length. In this case, the dimensions of the quarter, as a rule, do not exceed half the thickness of the plot.

3) Tongue and groove connection (rectangular and triangular);
This type of connection provides the plot with a groove on one side and a ridge on the other. The comb can be either rectangular or triangular, but the latter is rarely used as its strength is slightly inferior. The tongue and groove joint is quite popular and is often used by parquet manufacturers. The disadvantage of this connection is considered to be lower efficiency, since more boards are used.

4) Dovetail connection;
This type of fastening is a little similar to the previous one, only the comb has a trapezoidal shape. Well, hence the name.

Connecting boards into panels: a - into a smooth reveal, b - into a quarter, c - into a batten, d - into a groove and a rectangular ridge, e - into a groove and a triangular ridge, f - into a dovetail

Also, when assembling panels, dowels, tips in a groove and a comb are used with a lath glued into the end. Among the glued slats, there are triangular, rectangular and glued ones, and when using dowels, the dovetail groove is mainly chosen. All this is needed to securely fasten the shield.

Boards: a - with keys, 6 - with a tip in the groove and tongue, c - with a glued strip in the end, d - with a glued triangular strip, d - with a glued triangular strip.

Length connection

Popular types of joints along the length include: end-to-end, tongue-and-groove, tongue-and-groove, toothed adhesive joints, quarter joints, and rail joints. The toothed connection is the most popular because it has better strength.

Connecting bars along the length: a - end-to-end, b - in a groove and tongue, c - on a miter, d, e - on a toothed adhesive joint, f - in a quarter, g - on a rail

There is also splicing, where longer sections are joined together. This can happen in several ways. For example, half a tree, with an oblique cut, oblique and straight patch lock, oblique and straight tension lock and end-to-end. When choosing a half-tree splice required length connections should be 2 or 2.5 times the thickness of the timber. For greater reliability, dowels are used, for example, this can be found in the construction of cobblestone houses.

When using an oblique cut with trimming the end, the dimensions are 2.5 - 3 times the thickness of the beam and are also secured with dowels.

A connection with a straight or oblique patch lock is used in structures in which tensile forces are present. A straight rim lock is located on a support, and an oblique lock can be placed near the supports.

If you decide to use an oblique cut with an end trim, then the connection should have 2.5 or 3 times the thickness of the timber. In this case, dowels are also used.

When joining with a straight or oblique tension lock, you don’t have to worry about strength, but such a connection is difficult to manufacture, and when the wood dries out, the wedges weaken, so this joining method is not suitable for serious structures.

Butt splicing is when the two ends of the timber are placed on a support and securely connected with staples.

Splicing: a - half-tree, b - oblique cut, c - straight patch lock, d - oblique patch lock, e - straight tension lock, f - oblique tension lock, g - end-to-end

The connection of beams or logs can be found during the construction of walls either in the upper or bottom harness V frame houses. The main types of connections include half a tree, half-footed, thorny And corner frying pan.

Half-tree cutting is cutting down or cutting off half the thickness at the ends of the beams, after which they are connected at an angle of 90 degrees.

A half-foot joint is formed by cutting inclined planes at the ends of the beams, thanks to which the beams are tightly connected. The size of the slope is determined by the formula.

Notching with a corner frying pan is very similar to notching half a tree, but the distinguishing feature is that with such a connection, one of the beams loses a small part in width.

Building up

Building up beams and logs is the connection of elements in height, which is often used in the construction of pillars or matches.

There are several types of extensions:
1) end-to-end with a hidden spike;
2) end-to-end with a through ridge;
3) half-tree with bolt fastening;
4)half-tree with fastening with clamps;
5) half-wood with strip steel fastening;
6) oblique cut with fastening with clamps;
7) end-to-end with overlays;
8) bolting;

The length of the joints is usually 2-3 times the thickness of the beams being connected or 2-3 times the diameter of the logs.

Tenon connection

When tenoning bars, a tenon is cut on one, and an eye or socket is made on the other. Tenon joints are often used to create joinery, doors, windows or transoms. All connections are made with glue. You can use not only one, but also two or more spikes. The more tenons, the larger the gluing area. This type of connection can be divided into corner end, corner middle and corner box.

With an angular end connection, an open through tenon (one, two or three), a tenon with a through and non-through darkening, and insert dowels are used. Corner middle connections can be found on doors. Corner middle and end joints can additionally use nails, screws, dowels or bolts.

Corner tenon connections: a - open end-to-end single tenon UK-1, b - open end-to-end double tenon UK-2, c - open end-to-end triple tenon UK-3, d - non-through tenon with semi-darkness UK-4, d - end-to-end tenon with semi-darkness UK-5; non-through on the miter with a plug-in flat tenon UK-10, l - through on the miter with a plug-in flat tenon UK-11

Carpentry and construction furniture products consist of various parts, connected to each other in one way or another and mostly motionless. In some parts of collapsible and folding furniture, detachable connections are also used.

A part - a block, a board (plot), a shield - as the primary element of the product can be made from one piece of wood, from two or several pieces pre-glued together, and can also be veneered.

The connection of two or more parts forms a unit - a shield, a frame, a box, which are the structural elements of the product. From interconnected parts and assemblies, a simple carpentry product or a separate part of it is obtained - a plant, an assembly.

The parts are connected to each other by carpentry, glue or metal fasteners.

According to GOST 9330-60 "Wooden parts. Basic connections", the following groups of connections are distinguished:

by lenght- parts adjacent to each other at their ends; this connection is carried out by splicing or building up parts;
along the edges(coalescing) - two or more elements to obtain a wide detail;
corner end- parts converging at one angle or another to form the majority structural elements construction and furniture products;
angular median- a connection of elements, of which one either adjoins its end to the middle of the other (adjacency), or intersects it at one angle or another (intersection) to form basically shields;
box corner(box knitting) - wide elements; such connections are used when assembling boxes, boxes, etc. They can be end and middle (adjacent).

From the associated elements, a simple product or part of a complex product (unit) is formed, depending on the purpose of which the product is selected and method of connecting elements.

Splicing and extension. Due to the relatively short length of joinery parts, not exceeding the usual length of the boards and bars used, splicing and building up in joinery work is used mainly only in the manufacture of joinery and construction products (handrails, cornices, plinths, etc.), as well as when replacing unusable parts parts are new.

Splicing and extension is performed:

end to end when the elements are connected to each other with flat-cut ends at right or oblique angles;
overlay half a tree (Fig. 181, a);
round spikes, flat and oblique dovetail type (Fig. 181, b);
wedge lock(Fig. 181.c).

Bonding is used mainly for connecting narrow elements in order to obtain a part of greater width; much less often, bonding serves to increase thickness. The front sides of the product are veneered - covered with valuable wood. When bonding, the following methods of connecting elements are used:

Into a smooth puffer on glue(Fig. 182, a), which consists in the fact that the parts are tightly jointed with edges one to another and then glued together. After this, the parts are placed in special devices (workbenches, clamps, presses), compressed using screws, wedges, etc. and left in a compressed position until the glue dries. When compressed, excess adhesive is squeezed out along the joint line.
On spikes and dowels(Fig. 182, b, c), when sockets are cut out or holes are drilled in the edges of tightly jointed parts. into which rectangular spikes or round dowels are inserted. The thickness of the tenons should not exceed 1/3 of the thickness of the parts being connected.
At a quarter(Fig. 182, d), when in the edges of the parts to be joined up to half their thickness and the same width are selected, longitudinal recesses - quarters.
To the tongue(Fig. 182, d), in which a groove is selected in the middle in the edge of one part - a tongue of 1/3 thickness, and a ridge corresponding to the groove is selected in the edge of the other. The tongue and groove can be rectangular or trapezoidal (dovetail).
On the rail(Fig. 182, e), which differs from a tongue-and-groove connection in that grooves are selected in the edges of the parts to be connected into which the lath is inserted.
On dowels(Fig. 182, g), consisting in the fact that trapezoidal grooves tapering upward and along the length with a depth of 1/3 of the thickness of the board are selected in the parts to be connected. Dowel bars with a beveled edge corresponding to the profile of the selected groove are hammered into the grooves. In addition to holding the elements together, such a connection also serves as a means of protecting the shields from warping.
To the tip(Fig. 182, h, i), which consists in the fact that on end edge of the shield, processed in the form of a tongue-and-groove of a triangular, rectangular or other profile, a block is glued. This connection is used to protect panels from warping and to cover the end, which is difficult to clean and finish.

Joining into a smooth fugue using glue can be done with both parallel and non-parallel edges of the boards being joined. The latter connection is more economical in terms of material consumption, since boards with edges sawn along the rung of the tree are used, but it is less beautiful and more difficult to implement.

Joining on tenons and dowels is usually performed without gluing, mainly to connect parts or parts of a product lying on top of each other in order to prevent their displacement. Performing this type of rallying, especially on spikes, presents some difficulties.

Joining in a quarter, in a tongue and groove and on a lath with glue is stronger, joining in a smooth fugue, as it gives a larger gluing area. Racking on a batten is more profitable than in a quarter or tongue, because the wood is not spent on forming a quarter or tongue, and the batten itself is usually made from waste.

The best and most durable type of joining is a connection with a trapezoidal tongue ("stitching"). Making such a connection hand tools extremely difficult and rarely used. For this purpose, special stitching machines are currently used, which are widely used in the production of furniture and containers. A connection with a trapezoidal tongue can be made when the edges are not parallel in both the longitudinal and transverse directions, which makes it possible to fully use unedged boards with a rung, which give significant waste with other joining methods. The boards are positioned alternately in different directions with the core side and the butt end, which prevents warping of the shield as a whole.

Corner connections. Connecting parts at an angle, i.e. knitting corners, is the most common type of connection in carpentry. The forms of these compounds are very diverse; they can be divided into two main groups: frame and box.

There are the following methods of corner connections:

Overlay(Fig. 183, a), which is the simplest, but at the same time the least durable of all corner joints. At the end of each part to be joined, wood is selected up to half its thickness.
Straight frame tenon(Fig. 183, b, c, d), which is the main type of corner connection of various parts in carpentry. Thorn- part of a bar or part is included in nest, selected in another bar or part. Shish is usually obtained by processing the end of a block. In accordance with the required joint strength, which depends on the total area of the surfaces to be glued, the frame tenon is made single, double or triple. The socket into which the spike is inserted is open on one side (blind socket) and on both sides (through socket). A hole open on three sides is called eyelet or eyelet. The nest is in the middle part of the bar, and the eye is at its end. A through socket is usually made in cases where the product is painted with opaque paint, while a blind socket is made when the outer front side must be clean. If it is undesirable to have the end end of the tenon open, then instead of an eye they make a blind nest with darkness, that is, with a narrowed tenon. This hides defects when making a socket and increases the strength of the corner joint, since the tenon is clamped on four sides, and not on two sides, as in an eyelet.
Oblique thorn"dovetail" (Fig. 183, e) - the connection is more durable than with a straight tenon. The tenon and eye are not sawed parallel to the edges of the bars; The base of the tenon is made equal to 1/3, and the end - 3/5 of the thickness of the bar.
On the dowels(Fig. 183, e), sometimes called knitting on round insert dowels or dowels. This connection is less durable than a tenon connection; at the same time, it is more economical, since it does not require an allowance for the tenon.
On the nose(Fig. 183, g, h, i), when the ends of the bars are cut at an oblique angle. Bars of both the same and different widths and converging at any angle. To increase the strength of the connection, it is made halfway across the tree with a slotted or blind tenon (on a mustache with a hidden tenon), and sometimes with an inserted open or hidden tenon.

Trimming corner joints in bars with figured processed edges (mouldings) are made in two ways: processed finger joint rectangular in shape with the shaped part being trimmed to a miter or a tenon joint is made in accordance with the profile of the bars being connected. The first method, which is simpler (but produces a less durable connection), is applicable when manual processing, the second is used for machine processing of parts, ensuring the necessary accuracy of execution.

Nodal connections in products painted with opaque paint are strengthened with wooden nails (pins) driven into drilled holes.

Adjacent connections(Fig. 184) are a type of corner joint: the end of one bar is adjacent to the middle part of the other. They are made with an overlay (half-tree), with a straight and oblique tenon, through or semi-secret. Sometimes connections are made on inserted round tenons (dowels).

Rice. 185. Box corner joints: a - straight open tenon; b - oblique open spike; c - open dovetail spike; g - into the tongue on the insert rail; d - into the tongue and groove with open and closed end; e - on insertable flat and round tenons; g - with a dovetail spike; h - with a hidden dovetail tenon; and - on the mustache with an insert strip; k - on a mustache with a comb; l - with glued boss

Box corner joints(Fig. 185) boards or panels are widely used in carpentry and furniture. They are made with straight and oblique tenons of the “dovetail” or “frying pan” type. The number of spikes depends on the width and thickness of the parts or shields being connected. There are tenons at the ends of both connected parts, and the shield - the part with the eyelet on the edge of the edge - has one more tenon than the corresponding adjacent part.

Box connections They can be through, deaf, semi-recessed and deaf with a clear mustache. Through connections are used for parts located inside the product, also on its front sides if they are covered with plywood or opaque paint. Parts that are open on only one side are connected in a semi-flush manner, and parts that are open on all sides are connected in a hidden manner. Box corner joints are also made with plug-in tenons, but such joints are the least durable.

Box connections(Fig. 186) are made with straight through tenons and grooves with a ridge: triangular, rectangular, trapezoidal (reward). Groove connections are used in cases where outside It is undesirable to have protruding ends.

Glue connection. In carpentry and furniture production, adhesive joints are used relatively widely. A connection using only glue is strong enough, provided that the parts are properly fitted and properly glued together.

This method is used not only for joining parts into a board with a smooth fugue, but also for preparing plywood boards (gluing boards onto the face) and gluing plywood onto a frame, veneering and cladding (gluing plywood and boards different breeds) for producing thick parts (stands, legs, etc.) from thin bars and planks, as well as for gluing small bars to finished products (mouldings, baseboards, cornices, glazing beads, etc.).

Veneering. Pasting plain wood with thin planks (cladding) and veneering - pasting sheets (plywood) of more valuable wood is a special type of adhesive connection to improve the appearance of the product and increase its strength.

Depending on the production method, sawn, planed (knife) and peeled plywood are distinguished.

The parts are veneered on one or both sides; double-sided veneering significantly increases the strength of the product. Plywood is glued in one or two or more layers.

With one-sided veneering, the plywood is glued with fibers parallel to the fibers of the base (frame, frame or trim), and with double-sided veneering - mutually perpendicular.

Due to shrinkage or drying of the glue and warping of the plywood that dries out after moistening, the base - a board or shield - warps (Fig. 187, a) and a concavity is formed on the surface covered with plywood. This warping is greater, the smaller the ratio of the thickness of the base to its width. Veneering a well-dried block, the thickness of which is at least half the width, does not at all entail its warping.

Gluing plywood to the right (core) side of the block reduces warping of the base and, by creating a convexity on the right side, it is possible to compensate for the arching resulting from shrinkage of the glue and warping of the plywood.

Double-sided veneering (Fig. 187, b) does not cause warping of the part. In this case, the internal, non-front sides of the part can be covered with plywood of simple species, and the front sides with plywood of more valuable species.

It is often necessary to cover timber parts on three or four sides. In this case, plywood is glued to the wide edges, and plywood or solid wood lining to the narrow edges (Fig. 187, c, d).

The veneered surface is prepared accordingly: knots are drilled out and the holes are filled with wooden plugs; cracks and pins are sealed wooden inserts or putty; the surface is precisely leveled. The ends, which are usually difficult to veneer, are either glued and then (after the glue has dried) lined with zinubel, or pasted over with longitudinal blocks.

Plywood for the front and inner layers is cut into pieces of the required length, its edges are jointed and joined (pulled) into a sheet (set) according to the dimensions of the surface to be glued.

Plywood screed made on the table. The sheets are laid out with jointed edges one to the other, attached to the table with small nails, the seams and the surface of the plywood at the seams are wide 15 mm lubricate with glue and apply strips of paper the width of 15 mm. After the gluing has dried, the nails are pulled out, the set is removed and glued to the board.

Using the wood texture and using the appropriate arrangement (set) of plywood sheets, you can get a beautiful pattern and give the plywood product an artistic look.

In Fig. 188 shown different kinds set of plywood.

According to the specified veneering and set, plywood sheets are prepared.

Face plywood is selected after it has been cut to size (with allowance) and its edges have been smoothed. The selection is made in one of the following two ways: the sheets cut from the trunk are laid out, turning over every second sheet (as if unfolding the leaves of an open book) or simply shifted without turning over. In the first case, one sheet will turn out to be facing upward with the core (right) side, and the other sheet - with the sapwood (left). In the second case, all the sheets will turn out to be facing upward with one side - the core or sapwood - side.

The first method (unrolling) is used for plywood with tough wood that is less susceptible to cracking. Spiky wood (for example, oak) cannot be placed on the face with the left (sapwood) side up, since when drying, the plywood sheet will warp, bending upward, while the sheets facing left side down will be pressed tightly against the base when warped, and in this case the cracks will be barely noticeable. Therefore, when picking up the plywood, they move the plywood, turning all the sheets with the left side towards the base.

Connection of elements from different materials. For the production of furniture, currently used, in addition to solid wood, are chipboards and fibreboards, wood and other plastics, non-ferrous metals, etc. The connections of such materials with solid wood differ from the above connections.

Elements made of particle boards and fibreboards, which have a higher sensitivity to moisture, lower strength and an unsightly surface, are usually combined with valuable wood. The following connections are used (Fig. 189): gluing the front surfaces with veneer and planed plywood, a width connection with a smooth reveal and with an insert strip, miter corner joints with insert strips and dowels, with an insert pilaster made of wood with a smooth reveal and with an insert strip , median joints on a smooth reveal and in tongue and groove, sealing edges with wood. The connections are secured using resin adhesives, screws and special clamps.

Laminates are attached to wood using carbinol glue or screws and clamps.

Connections with screws, staples and nails.Screw connection used in dismountable products, as well as in products exposed to moisture, in which the adhesive connection is unreliable. Screw connections are sometimes used to simplify work when gluing or knitting parts is difficult.

Almost all fittings are fastened with screws: hinges, hinges, handles, locks and various decorations, as well as some wooden parts: glazing beads, trims, etc.

Fastening with dowels(Fig. 190) is used mainly for fastening tenon joints. To fasten parts made of soft wood, dowels are made wedge-shaped, with a pointed end, and are made from hardwood; To fasten hardwood, round dowels made of soft wood are used. Pin thickness from 3 to 12 mm.

The dowels are driven into the holes in a glued and pressed joint. Their ends are smeared with glue and hammered in with hammer blows, while the hard dowel is pressed into the wood of the joint, and the soft dowel is pressed into the hole. With one pin, it is placed in the center of the connection, and with two, each of them is placed at a distance of 1/4 diagonally from the inner and outer corners.

Connections with metal clamps are becoming more widespread. The clamps used are very diverse.

Stitching parts using wavy plates (Fig. 191, a) consists of driving (deepening) half of the plate lengthwise into one part, and the second half into another. This is most applicable when assembling bars into a frame for subsequent gluing with plywood (hollow panel) or when assembling a massive board panel for the same purpose.

Mustache connection made using a steel plate driven into the parts to be connected (Fig. 191, b).

Rallying on the rings(Fig. 191, c) consists in choosing a groove for the ring in the parts being connected, into which a special ring is placed that tightens the parts being connected.

Metal fasteners to strengthen the binding of wooden parts, it is most often used in the form of a metal square placed on top (Fig. 191, d).

Along with metal fasteners, they use wooden squares, bosses or crackers (Fig. 191, e), secured with glue and screws.

It will be useful for novice home craftsmen to learn about methods for joining wooden parts. We dedicate to this topic brief educational program, which will describe the main types of carpentry joints and joints using glue, nails, screws or dowels, or without them at all.

Rules for selecting a connection depending on the type of load

End connections are the simplest; they are used when it is necessary to extend a part. Such connections best withstand compression loads, however, when cutting locks of a special shape, good resistance to twisting, stretching and bending can be achieved. The standard version of the end connection is with trimming to half the thickness of both parts. The cut can be straight or oblique; if necessary, to prevent bending, stretching or twisting, a spike or a spike is cut at the end of each cut. obtuse angle, or make a stepped cut, forming a kind of “lock”.

1 - straight half-wood overlay; 2 — oblique pad; 3 - straight overlay with a stepped joint; 4 — half-timber overlay with an oblique joint; 5 — oblique patch lock; 6 - half-tree connection with an oblique tenon

Corner and side joints are used to connect straight parts into a truss or frame. Usually this part of the structure is supporting, so the main loads occur in displacement and compression. If the structure is experiencing a static intended load, a rectangular tenon is cut on one of the parts, and a groove or eye of appropriate dimensions is cut on the other. If action on breaking the structure is possible, the tenon and groove are cut in the shape of a trapezoid.

Corner connections: 1 - with an open through tenon; 2 - with a blind closed tenon; 3 - with a through oblique tenon

Overhead cross and T-shaped connections are used, as a rule, for additional connections between critical structural parts. The main load in them is compression, displacement and rupture. The first two types of load are eliminated by cutting half a tree or less, followed by combining the parts. The shoulders of the notches take the main load; all that remains is to secure the connection with screws or overhead staples. In some cases, to strengthen the connection, a dowel is used or a tenon with a wedge is cut out.

1 - cross connection with a half-wood overlay; 2 — cross connection with fit into one socket; 3 - T-shaped connection with a hidden oblique tenon; 4 - T-shaped connection with a straight stepped overlay

A separate type of connection is box connection. They are intended for connecting boards at right angles. Typically, for a box joint, teeth are cut on each board, the width of which is equal to the distance between them. On different boards, the teeth are cut with an offset, so when connected, the corner of the boards looks like one whole. The teeth can also be wedge-shaped, preventing the corner from breaking in one direction, or they can be additionally secured with glue or nails.

Box corner joints: 1 - with straight through tenons; 2 - with oblique through spikes

How to make a tenon joint

To make a tenon joint, you need to outline both parts with a marking line along all edges at a distance from the end equal to the width of the joint. On two opposite sides and the end, the body of the tenon is marked with lines; the markings on both parts are completely identical.

The tenon is cut from the sides with a hacksaw for a cross cut and the wood is chopped using a chisel. The width of the tenon is made 2-3 mm larger for subsequent precise processing with a knife or chisel. The groove is cut with a hacksaw for a longitudinal cut and chipped with a chisel, also leaving a small allowance for processing. Next comes the fitting, during which the parts are combined and the tightest fit is achieved.

With a T-shaped tenon joint, a central tenon or groove is cut on one of the parts, and an eye is hollowed out on the other, or two side cuts are made, depending on the type of the first part. To make an eye, use a chisel, turning the inclined part of the blade into the hole. If the eye is not solid, I make the tenon 8-10 mm deeper and cut off its end in the shape of an expanded wedge. This way, when driving, the tenon will open itself and the part will be firmly seated.

To connect wide parts, you can use a box connection by cutting several tenons and grooves. The easiest way to secure a tenon joint is to drill through it across the tenons and drive a wooden dowel (window corner joint) into the hole.

How to join boards with glue

A very popular method of joining boards and bars is longitudinal and transverse gluing. When connecting boards with the wide side, the end can be smooth, although in most cases a tongue-and-groove profile is used. It is very important to tightly fit the parts so that the glue layer is as thin as possible, this is the only way to achieve maximum strength. Sometimes a small amount of cotton fiber is applied to the end, lubricated with glue, this improves the quality of the coupling.

The boards can also be joined in profile, but this will require wedge-shaped gear cutting of both ends with the teeth offset to the floor for different parts. At home, this operation can be performed using a hand router.

Used for gluing parts casein glue or high concentration PVA, sifted wood flour is added to the adhesive to add strength. The surfaces are covered with glue and kept in air for 3-5 minutes, after which they are placed under pressure or squeezed with clamps. This connection is stronger than the wood itself and never breaks along the joint.

How to join elements of load-bearing structures

For load-bearing structures Two types of connections are used - extension and articulation. The easiest way to join two parts is to make a half-thick cut with a hacksaw at the same distance from the ends, and then chop off the excess wood with an ax. Once the two pieces are aligned, the joint is usually secured by two flashing strips nailed to the side of the cut. Gluing is also possible, but only if the parts fit tightly.

The ends cut into half a tree can be brought together at almost any angle; this is the main method of joining roof trusses. To fasten the parts, an additional tightening tie is required: the timber is applied to the connected parts from the side at a distance of 30-50 cm from the corner and cut to half the thickness at the points of contact, and then the structure is fastened with nails.

Often vertical and inclined structures need support, for example when connecting a rafter system to floor beams. In this case, the landing slots are cut on the horizontal beam into which the racks will be inserted. It is very important to maintain the angle of inclination and cut no more than a third of the thickness of the timber.

Connections with special connections

Almost all carpentry joints are made with additional reinforcing ties. In the very simple example the role of these is played by nails or screws.

When building up parts, the assembly can be strengthened through bolted connection, clamps, staples and capercaillie, or it is simply wrapped with cold-rolled wire. Spliced vertical supports It is enough to fasten it with two overhead strips - wooden or metal.

Corner joints are most often secured with staples, overlay plates or angles. In cases where it is necessary to maintain a slight mobility of the connection, use one through bolt, which either stitches across the place where the parts are overlayed, or tightens them in the longitudinal direction with a minimum distance from the overlay.

The place where the special connection is attached must be removed from the edge by at least 10 diameters of the fastening element and have no defects. It is important to remember that often ties do not provide the overall strength of the connection, but only compensate for the unaccounted load.