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Types of connections of wooden elements. Types of wooden connections. Basic options. Selecting a rebate on a wood cutting machine. Increase the open time of your glue

Carpentry, construction and furniture products consist of various parts connected to each other in one way or another and mostly immovably. 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 an assembly - a shield, a frame, a box, which are the structural elements of the product. From interconnected parts and assemblies a simple carpentry or a separate part of it - a plant, unit.

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 way 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:

1. end to end when the elements are connected to each other with flat-cut ends at right or oblique angles;
2. overlay half a tree (Fig. 181, a);
3. round spikes, flat and oblique dovetail type (Fig. 181, b);
4. 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:

1. 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.
2. 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.
3. 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.
4. 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).
5. 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.
6. 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.
7. To the tip(Fig. 182, h, i), which consists in gluing a block onto the end edge of the shield, processed in the form of a tongue-and-groove ridge of a triangular, rectangular or other profile. 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 large area gluing. 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 look joining - connection with a trapezoidal tongue ("stitching"). Making such a connection with hand tools is extremely difficult and is rarely used. For this purpose, special stitching machines are currently used, receiving wide application in the production of furniture and packaging. 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 arranged alternately in different sides 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:

1. 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.
2. 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 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
3. . 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
4. "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
5. (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 can be connected to the miter. 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 shape with trimming the figured part into a miter or making a tenon joint according to 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

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 a tongue and groove with an 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. End-to-end 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 used in cases where it is undesirable to have protruding ends on the outside.

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 adjusted and properly glued together.

This method is used not only for joining parts into a board into a smooth fugue, but also for preparing plywood boards (gluing boards onto the face) and gluing plywood onto a frame, veneering and cladding (sticking plywood and boards of different types) to obtain from thin bars and boards thick parts (stands, legs, etc.), as well as for gluing small bars to finished products(mouldings, skirting boards, 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 frame), 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 is possible by creating a convexity on right side, compensate for the bending 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 chips are sealed with 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 shows different types of plywood sets.

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 sheets open book) or simply shift 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 subject 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 knitting wooden parts 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.

There are a myriad of joints you can use to join wood pieces together. The names and classifications of joinery and carpentry joints, as a rule, vary significantly depending on the country, region and even school of woodworking. The skill lies in the precision of execution to ensure a properly functioning connection that can withstand the loads intended for it.

Initial information

Connection categories

All connections (in carpentry they are called ties) of wooden parts according to their area of ​​application can be divided into three categories (foreign version of the classification):

• box;
• frame (frame);
• for joining/merging.

Box connections are used, for example, in the manufacture drawers and arrangement of cabinets, frames are used in window frames and doors, and joining/merging is used to obtain parts of increased width/length.

Many connections can be used in different categories, for example, butt connections are used in all three categories.

Preparation of material

Even planed lumber may need some preparation.

• Cut the material with a margin of width and thickness for further planing. Don't cut the length yet.
• Choose the best quality surface - the front side. Plane it along its entire length. Check with a straight edge.
  After final alignment, make a mark for the front side with a pencil.
• Plane the front - clean - edge. Check with a straight edge and a square against the front side. Use planing to smooth out any warping. Mark the clean edge.
• Using a thicknesser, mark the required thickness along all edges of the part contour. Plan to this risk. Check with a straight edge.
• Repeat for width.
• Now mark the length and the actual connections. Mark from the front side to the clean edge.

Lumber marking

Be careful when marking lumber. Make sufficient allowances for the width of cuts, planing thickness and connections.

Take all readings from the front side and the clean edge, on which place the appropriate marks. In frame and cabinet designs, these marks should face inward to improve manufacturing accuracy. To make sorting and assembling easier, number the parts on the front side as they are manufactured, to indicate, for example, that side 1 connects to end 1.

When marking identical parts, carefully align them and make markings on all workpieces at once. This will ensure the markup is identical. When marking profile elements, keep in mind that there may be “right” and “left” parts.

Butt joints

These are the simplest of carpentry joints. They can fall into all three categories of compounds.

Assembly

The butt joint can be strengthened with nails driven in at an angle. Drive the nails in randomly.

Trim the ends of the two pieces evenly and connect them. Secure with nails or screws. Before this, you can apply glue to the parts to strengthen the fixation. Butt joints in frame structures can be reinforced with a steel plate or a wavy key on the outside, or with a wooden block secured from the inside.

Pin/dowel connections

Wooden dowels - today they are increasingly called dowels - can be used to strengthen the connection. These insertable round tenons increase shear (shear) strength and, due to the adhesive, secure the assembly more reliably. Dowel joints can be used as frame joints (furniture), box joints (cabinets) or for joining/splicing (panels).

Assembling the dowel connection

1. Carefully cut out all components, following the exact dimensions. Mark the position of the crossbar on the face and clean edge of the post.

2. Mark center lines for the dowels on the end of the crossbar. The distance from each end should be at least half the thickness of the material. A wide crossbar may require more than two dowels.

Mark the center lines for the dowels at the end of the crossbar and use the square to transfer them to the rack.

3. Lay the rack and bar face up. Using the square, transfer the center lines to the stand. Number and label all connections if there is more than one pair of posts and crossbars.

4. Transfer these markings to the clean edge of the post and the ends of the crossbar.

5. From the front side, use a thicknesser to draw a line in the center of the material, crossing the marking lines. This will mark the centers of the holes for the dowels.

Use a thicknesser to draw a center line, crossing the marking lines, which will show the centers of the holes for the dowels.

6. Using an electric drill with a twist drill bit or a hand drill with a spade bit, drill holes in all the parts. The drill must have a center point and scorers. The hole across the fibers should have a depth of approximately 2.5 times the diameter of the dowel, and the hole in the end should have a depth equal to approximately 3 times the diameter. For each hole, make an allowance of 2 mm; the dowel should not reach the bottom by this distance.

7. Use a countersink to remove excess fibers from the top of the holes. This will also make it easier to install the dowel and create space for the adhesive to secure the joint.

Nageli

The dowel must have a longitudinal groove (now standard dowels are made with longitudinal ribs), along which excess glue will be removed when assembling the joint. If the dowel does not have a groove, then plane it flat on one side, which will give the same result. The ends should be chamfered to facilitate assembly and prevent damage to the hole by the dowel. And here, if the dowels do not have a chamfer, make it with a file or grind the edges of their ends.

Using centers to mark dowels

Mark and drill the crossbars. Insert special dowel centers into the holes for the dowels. Align the crossbar with the post markings and press the pieces together. The points of the centers will make marks on the stand. Drill holes through them. As an alternative, you can make a template from a wooden block, drill holes in it, fix the template on the part and drill holes for dowels through the holes in it.

Using a conductor for a dowel connection

A metal jig for dowel connections greatly facilitates marking and drilling holes for dowels. In box joints, the jig can be used at the ends, but it will not work on the faces of wide panels.

conductor for pin connections

1. Mark center lines on the front side of the material where the dowel holes should be. Select a suitable drill guide and insert it into the jig.

2. Align the alignment marks on the side of the jig and secure the movable support of the guide bushing.

3. Install the jig onto the part. Align the centering notch with the center line of the dowel hole. Tighten.

4. Install a drill depth stop on the drill in the required location.

Rally

To obtain a wider wooden part, you can use dowels to connect two parts of the same thickness along the edge. Place two boards with their wide sides together, align their ends exactly, and clamp the pair in a vice. On the clean edge, draw perpendicular lines to indicate the center lines of each dowel. In the middle of the edge of each board, use a thicknesser to score marks across each previously marked center line. The intersection points will be the centers of the holes for the dowels.

The nail joint is neat and durable.

Notch / mortise connections

A notch, mortise or groove connection is called a corner or median connection, when the end of one part is attached to the layer and another part. It is based on a butt joint with an end cut made in the face. Used in frame (house frames) or box (cabinets) connections.

Types of jack/punch connections

The main types of notch joints are the t-notch in the dark/semi-dark (often this term is replaced by the term “flush/semi-dark”), which looks like a butt joint, but is stronger, the corner notch (corner connection) in the quarter and the corner notch in the dark/semi-dark. A corner notch into a rebate and a corner notch into a rebate with darkness/semi-darkness are made in the same way, but the rebate is made deeper - two-thirds of the material is selected.

Carrying out cutting

1. Mark a groove on the front side of the material. The distance between the two lines is equal to the thickness of the second part. Continue the lines to both edges.

2. Using a thickness gauge, mark the depth of the groove between the marking lines on the edges. The depth is usually made from one quarter to one third of the thickness of the part. Mark the waste portion of the material.

3. Use a C-shaped clamp to securely fasten the part. Saw the shoulders on the outgoing side of the marking lines to the required depth. If the groove is wide, make additional cuts in the waste to make it easier to remove the material with a chisel.

Saw close to the marking line on the waste side, making intermediate cuts with a wide groove.

4. Using a chisel on both sides, remove excess material and check that the bottom is even. You can use a primer to level the bottom.

Use a chisel to remove waste, working from both sides, and level the bottom of the groove.

5. Check the fit; if the part fits too tightly, it may need to be trimmed. Check for squareness.

6. The notch connection can be strengthened in one of the following ways or a combination of them:

• gluing and clamping until the glue sets;
• screwing with screws through the face of the outer part;
• nailing at an angle through the face of the outer part;
• Nailing obliquely across a corner.

The notch connection is quite strong

Groove and side tongue joints

This is a combination of a quarter cut and a rebate cut. It is used in the manufacture of furniture and the installation of slopes for window openings.

Making a connection

1. Make the ends perpendicular to the longitudinal axes of both parts. Mark the shoulder on one part, measuring the thickness of the material from the end. Continue marking on both edges and the front side.

2. Mark the second shoulder from the end side; it should be at a distance of one third of the thickness of the material. Continue on both edges.

3. Using a thickness gauge, mark the depth of the groove (one-third of the thickness of the material) on the edges between the shoulder lines.

4. Using a hacksaw, cut through the shoulders to the thickness line. Remove waste with a chisel and check the alignment.

5. Using a thicknesser with the same setting, mark a line on the back side and on the edges of the second part.

Adviсe:

• Mortise and tongue-and-groove joints can be easily made using a router and a suitable guide - either for the groove only, or for both the groove and the tongue. Recommendations for proper operation with a router, see p. 35.
• If the comb fits into the groove too tightly, trim the face (smooth) side of the comb or sand it with sandpaper.

6. From the front side, use a thicknesser to mark the edges towards the end and at the end itself. Saw along the lines of the planer with a hacksaw. Don't cut too deep as this will weaken the joint.

7. Using a chisel from the end, remove the waste. Check fit and adjust if necessary.

Half-tree connections

Half-timber joints are frame joints that are used to join parts together face to face or along an edge. The joint is made by removing the same amount of material from each piece so that they fit flush with each other.

Types of half-tree connections

There are six main types of half-timber joints: transverse, corner, flush, miter, dovetail and splice.

Making a half-tree corner connection

1. Align the ends of both parts. On the top side of one of the parts, draw a line perpendicular to the edges, stepping back from the end to the width of the second part. Repeat on the underside of the second piece.

2. Set the thicknesser to half the thickness of the parts and draw a line on the ends and edges of both parts. Mark the waste on the top side of one piece and the bottom side of the other piece.

3. Clamp the part in a vice at an angle of 45° (faces vertical). Saw carefully along the grain, close to the thickness line on the waste side, until the saw is diagonal. Turn the piece over and continue cutting carefully, gradually lifting the saw handle until the saw is aligned with the shoulder line on both edges.

4. Remove the part from the vice and place it on the surface. Press it tightly to the tsulaga and clamp it with a clamp.

5. Saw the shoulder to the previously made cut and remove the waste. Use a chisel to smooth out any unevenness in the sample. Check that the cut is neat.

6. Repeat the process on the second piece.

7. Check the fit of the parts and, if necessary, level them with a chisel. The connection must be rectangular, flush, without gaps or backlash.

8. The connection can be strengthened with nails, screws, and glue.

Miter corner connections

Miter corner joints are made by bevelling the ends and hide the end grain and are aesthetically more consistent with the angular rotation of the decorative trim.

Types of miter corner joints

To bevel the ends in a miter joint, the angle at which the parts meet is divided in half. In a traditional connection, this angle is 90°, so each end is cut at 45°, but the angle can be either obtuse or acute. In uneven miter corner joints, parts with different widths are connected.

Performing miter joints

1. Mark the length of the pieces, keeping in mind that it should be measured along the long side, since the bevel will reduce the length inside the corner.

2. Having decided on the length, mark a line at 45° - on the edge or on the face, depending on where the bevel will be cut.

3. Using a combination square, transfer the markings to all sides of the part.

4. When cutting by hand, use a miter box and a hacksaw or hand miter saw. Press the piece firmly against the back of the miter box - if it moves, the bevel will be uneven and the joint will not fit well. If you are simply sawing by hand, watch the process so as not to deviate from the marking lines on all sides of the part. A power miter saw, if you have one, will make a very clean bevel.

5. Place the two pieces together and check the fit. You can correct it by trimming the bevel surface with a plane. Firmly fix the part and work with a sharp plane, setting the knife overhang to a small extent.

6. The connection should be nailed through both parts. To do this, first place the parts on the surface and drive nails into the outer side of the bevel so that their tips slightly appear from the bevels.

Place nails in both parts so that the tips protrude slightly from the surface of the bevel.

7. Apply glue and press the joint tightly so that one part protrudes slightly and overlaps the other. First, drive nails into the protruding part. Under the blows of the hammer when hammering nails, the part will move slightly. The surfaces must be level. Nail the other side of the joint and countersink the nail heads. Check for squareness.

Drive the nails into the protruding part first and the hammer will move the joint into position.

8. If due to unevenness of the workmanship there is a small gap, smooth the connection on both sides with the round blade of a screwdriver. This will move the fibers, which will close the gap. If the gap is too large, you will either have to redo the connection or seal the gap with putty.

9. To strengthen the corner joint, you can glue a wooden block inside the corner if it is not visible. If appearance is important, the connection can be made using a tenon or secured with veneer dowels. Dowels or lamellas (standard flat plug-in tenons) can be used inside flat joints.

Miter splicing and cutting connection

A miter splice connects the ends of parts that are located on the same straight line, and a rip splice is used when it is necessary to connect two profile parts at an angle to each other.

Miter splicing

When miter splicing, the parts are connected with identical bevels at the ends in such a way that the same thickness of the parts remains unchanged.

Connection with cutter

A connection with a cut (with a cut, with a fit) is used when it is necessary to connect two parts with a profile in a corner, for example, two plinths or cornices. If the part moves during the process of fastening it, the gap will be less noticeable than with a miter joint.

1. Secure the first baseboard in place. Move the second plinth located along the wall close to it.

Clamp the first baseboard in place and press the second baseboard against it, lining it up with the wall.

2. Run a small wooden block with a pencil pressed to it along the profile surface of the fixed baseboard. The pencil will leave a marking line on the plinth being marked.

Using a block with a pencil pressed to it, with the tip pointed at the second plinth, draw along the relief of the first plinth, and the pencil will mark the cut line.

3. Cut along the marking line. Check the fit and adjust if necessary.

Complex profiles

Place the first plinth in place and, placing the second plinth in the miter box, make a bevel on it. The line formed by the profile side and the bevel will show the required shape. Cut along this line with a jigsaw.

Lug connections

Lug joints are used when there is a need to connect intersecting parts located “On Edge”, either at the corner or in the middle (for example, the corner of a window sash or where a table leg meets a crossbar).

Types of lug connections

The most common types of eyelet connections are corner and T-shaped (T-shaped). For strength, the connection must be glued, but it can be strengthened with a dowel.

Making an eyelet connection

1. Mark the same as for, but divide the thickness of the material by three to determine one third. Mark the waste on both parts. On one part you will need to select the middle. This groove is called an eye. On the second part, both side parts of the material are removed, and the remaining middle part is called a tenon.

2. Saw along the grain to the shoulder line along the marking lines on the waste side. Use a hacksaw to cut out the shoulders, and you will get a tenon.

3. Working from both sides, remove material from the eye with a chisel/mortise chisel or jigsaw.

4. Check the fit and adjust with a chisel if necessary. Apply glue to the joint surfaces. Check for squareness. Using a C-clamp, clamp the joint while the glue hardens.

Tenon to socket connection

Tenon-to-socket joints, or simply tenon joints, are used when two parts are joined at an angle or intersection. It is probably the strongest of all frame joints in joinery and is used in the making of doors, window frames and furniture.

Types of tenon-to-socket connections

The two main types of tenon joints are the usual tenon-to-socket joint and the stepped tenon-to-socket joint (semi-dark). The tenon and socket make up approximately two-thirds of the width of the material. The socket is widened on one side of the groove (semi-dark), and a tenon step is inserted into it from its corresponding side. Semi-darkness helps prevent the thorn from being turned out of the socket.

Conventional tenon-to-socket connection

1. Determine the joint position on both pieces and mark all sides of the material. The marking shows the width of the intersecting part. The tenon will be at the end of the crossbar, and the socket will go through the post. The tenon should have a small allowance in length for further stripping of the joint.

2. Select a chisel that is as close in size as possible to a third of the thickness of the material. Set the thicknesser to the size of the chisel and mark the socket in the middle of the post between the previously marked marking lines. Work from the front side. If desired, you can set the thicknesser solution to a third of the thickness of the material and work with it on both sides.

H. In the same way, mark the tenon on the end and both sides until you mark the shoulders on the crossbar.

4. In a vice, clamp an auxiliary support in the form of a piece of wood high enough so that you can attach the stand to it, turned “on edge.” Secure the stand to the support, placing the clamp next to the socket markings.

5. Cut out a nest with a chisel, making an allowance inwards of about 3 mm from each end so as not to damage the edges when removing waste. Hold the chisel straight, maintaining parallelism
its edges are the plane of the rack. Make the first cut strictly vertically, placing the sharpening bevel towards the middle of the socket. Repeat from the other end.

6. Make several intermediate cuts, holding the chisel at a slight angle and with the sharpening bevel down. Select a retreat, using the chisel as a lever. Having gone deeper by 5 mm, make more cuts and select a waste. Continue until about halfway thick. Turn the piece over and work the same way on the other side.

7. After removing the main part of the waste, clean out the nest and cut off the previously left allowance to the marking lines on each side.

8. Cut a tenon along the fibers, running a hacksaw along the marking line on the waste side, and cut out the shoulders.

9. Check fit and adjust if necessary. The shoulders of the tenon should fit neatly into the post, the connection should be perpendicular and have no play.

10. To secure, you can insert wedges on both sides of the tenon. The gap for this is made in the socket. Working with a chisel from the outside of the socket, widen it to about two-thirds of the depth with a 1:8 slope. The wedges are made with the same bias.

11. Apply glue and squeeze tightly. Check for squareness. Apply glue to the wedges and drive them into place. Saw off the tenon allowance and remove excess glue.

Other tenon joints

Tenon joints for window frames and doors are somewhat different from tenon joints in semi-darkness, although the technique is the same. Inside there is a fold and/or lining for glass or panel (panel). When making a tenon-to-socket connection on a part with a rebate, make the plane of the tenon in line with the edge of the rebate. One of the shoulders of the crossbar is made longer (to the depth of the fold), and the second is made shorter so as not to block the fold.

Tenon joints for parts with overlays have a shoulder that is cut to match the profile of the overlay. An alternative is to remove the trim from the edge of the socket and make a bevel or cut to match the mating piece.
Other types of tenon-to-socket connections:

• Side tenon - in the manufacture of doors.
• A hidden beveled tenon in semi-darkness (with a beveled step) - to hide the tenon.
• Tenon in the dark (tenon steps on both sides) - for relatively wide parts, such as bottom harness(bar) door.

All these connections can be through, or they can be blind, when the end of the tenon is not visible from reverse side racks. They can be strengthened with wedges or dowels.

Rally

Wide, high-quality timber is becoming increasingly difficult to find and very expensive. In addition, such wide boards are subject to very large shrinkage deformations, which makes working with them difficult. To join narrow boards along the edges into wide panels for tabletops or workbench covers, they use bonding.

Preparation

Before starting the bonding itself, you must do the following:

• If possible, select radial sawn boards. They are less susceptible to shrinkage deformations than tangential sawn timber. If tangentially sawn boards are used, then place their core side alternately in one direction and the other.
• Try not to combine materials with different ways cutting into one panel.
• Never join boards of different types of wood unless they have been properly dried. They will shrink and crack differently.
• If possible, place the boards with the grain in the same direction.
• Be sure to cut the material to size before joining.
• Use only good quality glue.
• If the wood will be polished, select the texture or color.

Rallying on a smooth fugue

1. Lay out all the boards face up. To facilitate subsequent assembly, mark the edges with a continuous pencil line drawn along the joints at an angle.

2. Plane straight edges and check fit to appropriate adjacent boards. Align the ends or pencil lines each time.

3. Make sure there are no gaps and that the entire surface is flat. If you squeeze the gap with a clamp or fill it with putty, the connection will subsequently crack.

4. When planing short pieces, clamp two in a vise, right sides together, and plane both edges at the same time. There is no need to maintain the squareness of the edges, since when joining they will mutually compensate for their possible tilt.

5. Prepare as for a butt joint and apply glue. Using squeezing and rubbing, connect the two surfaces, squeezing out excess glue and helping the surfaces “suck” to each other.

Other ways to rally

Other bonding connections with different strengths are prepared in the same way. These include:

• with dowels (dowels);
• in tongue and groove;
• at a quarter.

Gluing and fixing with clamps

Gluing and fixing glued parts is an important part of woodworking, without which many products will lose strength.

Adhesives

The glue strengthens the connection, holding the parts together so that they cannot be easily pulled apart. When working with adhesives, be sure to wear protective gloves and follow the safety recommendations on the packaging. Clean the product from excess glue before it sets, as it can dull the plane knife and clog the abrasive sandpaper.

PVA (polyvinyl acetate)

PVA glue is a universal wood glue. While still wet, it can be wiped off with a cloth dampened with water. It perfectly glues loose surfaces, does not require long-term fixation for setting and sets in about an hour. PVA gives a fairly strong connection and sticks to almost any porous surface. Provides a permanent connection but is not heat or moisture resistant. Apply with a brush, or for large surfaces, dilute with water and apply with a paint roller. Since PVA glue has water base, then shrinks when setting.

Contact glue

Contact adhesive bonds immediately after application and joining of parts. Apply it to both surfaces and when the glue is dry to the touch, press them together. It is used for laminate or veneer to chipboard. No fixation required. Can be cleaned with solvent. Contact adhesive is flammable. Handle it in a well-ventilated area to reduce fumes. Not recommended for outdoor use as it is not moisture or heat resistant.

Epoxy adhesive

Epoxy glue is the strongest of the adhesives used in woodworking, and the most expensive. This is a two-component resin-based adhesive that does not shrink when set and softens when heated and does not creep under load. It is water-resistant and bonds to almost all materials, both porous and smooth, with the exception of thermoplastics, such as polyvinyl chloride (PVC) or plexiglass (plexiglass). Suitable for outdoor use. In an uncured form, it can be removed with a solvent.

Hot melt adhesive

Hot melt, solventless adhesive will stick to almost anything, including many plastics. Typically sold in the form of glue sticks that are inserted into a special electric glue gun. Apply glue, connect the surfaces and compress for 30 seconds. No fixation required. Can be cleaned with solvents.

Fixation clips

Clamps come in a variety of designs and sizes, most of which are called clamps, but usually only a couple of varieties are needed. Be sure to place a spacer between the clamp and the workpiece. wood waste to avoid indentations from the applied pressure.

Gluing and fixation technique

Before gluing, be sure to assemble the product “dry” - without glue. Lock as necessary to check connections and dimensions. If everything is fine, disassemble the product, arranging the parts in a convenient order. Mark the areas to be glued and prepare clamps with jaws/stops set at the required distance.

Frame assembly

Using a brush, spread the glue evenly onto all surfaces to be glued and quickly assemble the product. Remove excess glue and secure the assembly with clamps. Apply even pressure to compress the joints. The clamps must be perpendicular and parallel to the surfaces of the product.

Place the clamps as close to the connection as possible. Check the parallelism of the crossbars and align if necessary. Measure the diagonals - if they are the same, then the rectangularity of the product is maintained. If not, then a light but sharp blow to one end of the post can straighten the shape. Adjust the clamps if necessary.

If the frame does not lie flat on flat surface, then tap the protruding areas with a mallet through a wooden block as a spacer. If this does not help, you may need to loosen the clamps or use clamps to secure a piece of wood across the frame.

It will be useful for novice home craftsmen to learn about methods for joining wooden parts. We are devoting a short educational program to this topic, 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 an obtuse angle is cut at the end of each cut, or a stepped cut is made, 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.

To glue the parts together, casein glue or high concentration PVA is used; to give strength, sifted wood flour is added to the adhesive. 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 cut with a hacksaw to half the thickness on 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 with 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 with a through bolted connection, clamps, staples and capercaillie, or it can simply be wrapped with cold-rolled wire. It is enough to fasten the spliced ​​vertical supports 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.

They say about the coolest joiners and carpenters that they are able to build a house without a single nail. Japanese artisans, even amateurs, are one of those.

Several years ago, a young automotive industry worker, passionate about woodworking, came across a book describing traditional Japanese woodworking techniques. He was very fascinated by the descriptions of connecting parts without using nails, screws or glue. He wanted to learn how to do the same. But there were no diagrams for making fasteners in the book. Then the guy decided to draw them himself.

He used the free Fusion-360 service to model and animate parts. The Japanese translated the resulting result into gifs and posted it on a Twitter account called The Joinery. In almost a year, the young carpenter visualized 85 in various ways detachable connections.

The variety of mounts is truly amazing. With their help, you can make basically anything - a stool, a sofa, a table, and so on. The main thing is to have straight hands and a good, preferably electric, tool.

But even if manual labor you're not at all inspired, you'll probably enjoy watching GIFs. The grace with which the details fit together is mesmerizing.

Connections of wooden elements have the task of connecting mating Construction Materials, For example edged beams, so that they do not move relative to each other. Based on the position and direction of the wooden elements being connected, a distinction is made between longitudinal connections and corner connections, as well as connections at branches and crosses. Spatial connecting elements from steel sheet and plate steel plates with pre-drilled holes often replace carpenter joints.

Connections that must transmit forces of a certain magnitude and direction, such as compressive forces, are also called joints of connected wooden elements as rods, for example compressed rods. Compressed rods connected at an acute angle can be connected using notches. Other connections of wooden structures are made by joining wooden elements using connecting means.

Based on the type of connecting means, such connections are called nail or bolt, dowel or dowel connections. In wood construction, laminated veneers are also used. building construction. Because they have special advantages, the use of laminated timber structures is of increasing importance.

Longitudinal connections

There are longitudinal connections on supports and longitudinal connections in the span. Above the supports, perpendicular trunnions, a “toe-to-foot” joint and a partially “to-toe” trunnion joint are used (Fig. 1). To reinforce these joints, flat or round steel construction staples can be driven into the top or sides. Often wooden elements are butted head-on and secured only with construction staples. If, however, there are large tensile forces at the joint, for example, at purlins on the roof rafters, then both elements are butted head-on on a support and connected by side plates made of boards or perforated strips of corrosion-protected steel.

Rice. 1. Longitudinal connections

Purlins can also be made in the form cantilever-suspended(Gerber runs) or hinged purlins. Their joint is located in a place determined by calculation, not far from the support, in which the bending moments are equal to zero and where there are no bending forces (Fig. 2). There, the purlins are connected with a straight or oblique overlay. The incoming purlin is held in place by a screw bolt, also called a hinge bolt. The hinge bolt with washers must take the load from the suspended purlin.

Rice. 2. Longitudinal connections of Gerber purlins

Gerber purlins with a joint lying on top are impractical, since there is a danger that the purlins at the edge of the joint will come off. If the joint is suspended, if damaged, there is no danger of tearing off.

To connect Gerber purlins, spatial elements made of steel sheet are also used, which are also called Gerber connecting elements. They are attached with nails to the frontal butt ends of the purlins (see Fig. 2).

Corner connections

Corner joints are necessary when two logs or beams in a corner are joined at right or approximately right angles in the same plane. The most commonly used types of joints are cut-out trunnions, smooth corner foot and compressed foot (Fig. 3). With the help of cut-out trunnions and smooth corner paws, the ends of the thresholds, purlins and rafter legs lying on supports or protruding in a cantilever are connected. Nails or screws can be used to secure connections. The compressed paw has planes that enter each other obliquely. It is particularly suitable for connecting loaded, fully supported thresholds.

Rice. 3. Corner joints

Branches

When branching, a timber suitable at a right or oblique angle is in most cases superficially joined to another timber. In ordinary cases, a joint on axles is used, and in secondary structures a “claw” connection is also used. In addition, timber beams can be joined using metal spatial connecting elements. In trunnion joints, the thickness of the trunnion is approximately one third of the thickness of the beam. The axles have a length in most cases from 4 to 5 cm. The groove for the axle is made 1 cm deeper so that the compression force is transmitted not through the axle section, but through the large area of ​​the remaining cross-section of the beams.

When arranging axles, a distinction is made between normal axles that extend across the entire width of the beam, and protruding(hemp) axles, which are used for connections at the ends of beams (Fig. 4). If the beams in the connection do not approach each other at right angles, for example, with corner struts, then the axle at the strut should be made at right angles to the horizontal (or vertical) structural element (see Fig. 4).

Rice. 4. Trunnion connections

When installing trunnions in wooden beams and purlins, the trunnion must bear the entire load. It is more advantageous to carry out such connections using beam shoes made of corrosion-protected steel (Fig. 9). These shoes are secured with special nails in such a way as to prevent them from buckling and turning relative to the joint. In addition, the cross section of the beam is not weakened by the holes for the trunnions.

Cross connections

Wooden beams can intersect in one plane or with offset planes and be overhead or supporting. Beams intersecting in the same plane can intersect “IN THE PAW” if the weakening of the section does not play any role (Fig. 5). It is advisable to connect the intersecting overhead thresholds on the support beams with round dowels (pins) made of hard wood or steel with a length of 10 to 12 cm (Fig. 6).

Rice. 5. “claw” connection

Rice. 6. Connection using round keys (pins)

Side-joining beams receive good support on the pole if their connection is made “IN THE GROOT” (Fig. 7). To do this, the intersection planes of both elements are cut to a depth of 1.5 to 2.0 cm. This results in a non-shifting connection, which is secured with a screw bolt.

Rice. 7. “Groove” connection

When joining inclined and horizontal beams, as is usually the case when joining rafter legs with purlins - thresholds, a cutout is made in the rafter leg corresponding to the slope, which is called sidebar(Fig. 8).

Rice. 8. Inset of rafter leg

The depth of the cut in the rafter legs with a normal section height of 16 to 20 cm is from 2.5 to 3.5 cm. For fastening, use one nail that penetrates the threshold for a length of at least 12 cm, or a special anchor for attaching the rafters to the purlins.

Rice. 9. Connection with steel shoe

Cuttings

When cutting, a compressed rod entering at an acute angle is connected to another beam using one or more force-transmitting planes on its front side. Based on the number and position of force-transmitting planes, a distinction is made between a frontal notch, a notch with a tooth, and a double frontal notch with a tooth.

At frontal cut(also called the front stop) the receiving beam has a wedge-shaped cutout corresponding in shape to the end of the compressed rod (Fig. 10). The frontal plane should pass at an angle dividing the obtuse outer corner of the notch in half. The fastening bolt must have the same direction, guaranteeing the joint against lateral displacement. To mark the notches, parallels are drawn at the same distance from the sides of the angle, which must be divided in half. The connecting line between the point of their intersection and the vertex of an obtuse angle will be the bisector of this angle (see Fig. 10). The position of the fastening bolt is obtained if the distance between the bisector and the end of the notch is divided into three parts parallel to the bisector (see Fig. 10).

Rice. 10. Frontal cut

Under the action of a compressive force, the wood lying in front of the frontal part of the compressed rod works to slice(see Fig. 10). Since the permissible stress for cutting wood along the fibers is relatively small (0.9 MN/m2), the plane of the wood in front of the cut edge (cut plane) must be quite large. Since, in addition, cracking due to shrinkage should be taken into account, then, with rare exceptions, the length of the cut plane should not be less than 20 cm.

At reverse or gear notch the notch plane is cut at a right angle to the underside of the compressed rod (Fig. 11). Due to the fact that due to the eccentric connection in a gear notch there may be a risk of splitting of the compressed rod, it is necessary that the free end of the notch does not fit tightly to the support rod and a seam is provided between them.

Rice. 11. Tooth cutting

Double cut consists, as a rule, of a frontal notch in combination with a gear notch (Fig. 12). The direction of the notch planes is the same as is customary for each of the notches of this combination. However, the serrated notch in this case must be at least 1 cm deeper so that its cut plane is lower than the cut plane of the frontal notch. The fastening bolt should run parallel to the frontal part of the notch approximately halfway between the bisector and the top of the acute joint angle.

Rice. 12. Double cut

Cutting depth t v is limited according to DIN 1052. The determining factors for this are the contact angle (a) and the height h of the cut rod (Table 1).

Pin and bolt connections

In case of pin and bolt connections wooden beams or boards touching their sides are connected by cylindrical connecting elements, such as rod dowels, bolts with recessed heads and nuts, ordinary bolts and nuts. These rod dowels and bolts must prevent the wood members from moving in the joint plane, also called the shear plane. In this case, forces act perpendicular to the axis of the rod dowel or bolt. Dowels and bolts work in bending. In connecting wooden elements, all efforts are concentrated on the inner surface of the holes for dowels or bolts.

The number of rod dowels and bolts installed at the junction depends on the magnitude of the transmitted force. In this case, as a rule, at least two such elements should be installed (Fig. 13).

Rice. 13. Connection using rod dowels

In a single joint, many shear planes may be located adjacent to each other. Based on the number of cut planes that are connected by identical connecting elements, single-cut, double-cut and multi-cut dowel and bolt connections are distinguished (Fig. 14). According to DIN 1052, single-cut load-bearing connections using dowel rods must have at least four dowel rods.

Rice. 14. Bolted connections

For bolted connections, bolts and nuts made of steel with standardized diameters of 12, 16, 20 and 24 mm are mainly used. To prevent the head and nut of the bolt from cutting into the wood, strong steel washers should be placed under them. Minimum dimensions These washers are given for various bolt diameters in DIN 1052 (Table 2).

To prevent splintering of the connected wooden elements by the core dowels and bolts, these connecting means must be installed minimum distances between themselves, as well as from the loaded and unloaded ends. The minimum distances depend on the direction of the force, on the direction of the wood grain and on the diameter of the dowel rod or bolt db and do (Fig. 15 and 16). For load-bearing bolts and nuts, greater distances must be maintained between each other and from the loaded end than for rod dowels and bolts with hidden heads. But dowel rods or bolts with hidden heads located close to each other in the direction of the wood fibers should be spaced apart relative to the cut line so that the joints do not crack (see Fig. 15).

Rice. 15. Minimum distances for dowel rods and hidden head bolts

Rice. 16. Minimum distances in case of load-bearing bolts

Holes for pins and bolts are pre-drilled perpendicular to the cutting plane. For this purpose, electric drills with a frame with parallel movement are used. For pins, when drilling holes in wood, as well as when simultaneously drilling holes in wood and metal connecting elements, the diameter of the hole must correspond to the diameter of the pin.

Also, the holes for the bolts should be well suited to the diameter of the bolts. The diameter of the hole cannot be increased compared to the diameter of the bolt by more than 1 mm. With bolted connections, it is bad when the bolt sits loosely in the hole. It is also bad if, due to shrinkage of the wood, the clamp of the bolt in the hole gradually weakens. In this case, a backlash appears in the cut plane, which leads to even greater pressure from the bolt rod on the boundary planes of the hole walls (Fig. 17). Due to the associated flexibility, bolted connections cannot be used indefinitely. For simple buildings, such as sheds and sheds, as well as scaffolding, they can, however, be used. In any case, in the finished structure, the bolts must be tightened many times during operation.

Rice. 17. Backlash in bolted connections

Dowel connections

Dowels are fasteners made of solid wood or metal that are used together with bolts to connect smoothly joined wooden elements (Fig. 18). They are positioned in such a way that they act evenly on the surface of the elements being connected. In this case, the transmission of forces occurs only through the dowels, while the bolts provide a clamping effect in the connection so that the dowels cannot tip over. Slats made of flat or profile steel are also attached to wooden elements using dowels. To do this, use single-sided dowels or flat steel dowels. There are dowels various forms and types.

Rice. 18. Connecting wooden elements using dowels and bolts

When making dowel connections with pressed-in dowels, holes for bolts are first drilled in the elements being connected. After this, the wooden elements are again separated, and a groove is cut, if necessary, for the main plate. Depending on the construction technology, the dowel is completely or partially driven into the groove of one of the elements being connected using a mallet. For final clamping of a precisely aligned connection, special clamping bolts with a large washer are used. Connections with many or large pressed-in dowels are clamped using hydraulic press. When making connections with a large number of dowels, as is the case when making corner connections in frames made of laminated board elements, it is more preferable to use round plug-in dowels, since with pressed-in dowels the press-in pressure may be too high (Fig. 19).

Rice. 19. Dowel connection in the corner of the frame

Each dowel, as a rule, must correspond to one bolt and nut, the diameter of which depends on the size of the dowel (Table 3). The size of the washer is the same as for bolted connections. Depending on the magnitude of the force acting on the connection, larger or smaller dowels can be used. The most common diameters are from 50 to 165 mm. In the drawings, the size of the dowels is indicated by symbols (Table 4).

Table 3. Minimum dimensions for dowel connections
Outer diameter d d in mm	Bolt diameter d b in mm	Distance between dowels/distance from dowel to the end of the element, e db, in mm
50	M12	120
65	M16	140
85	M20	170
95	M24	200
115	M24	230
The values ​​are valid for the family of round press-in dowels type D.

Table 4. Drawing symbols for special types of dowels
Symbol	Dowel size
	from 40 to 55 mm
	from 56 to 70 mm
	from 71 to 85 mm
	from 86 to 100 mm
	Nominal dimensions > 100 mm

At placement of dowels You should maintain certain distances between the dowels and from the edges of the wooden elements. These minimum distances according to DIN 1052 depend on the type of dowel and its diameter (see Table 3).

The bolts and nuts of dowel joints are almost always passed through the center of the dowel. Only with rectangular and flat steel dowels do they lie outside the plane of the dowel. When tightening the nuts on the bolts, the washers should cut approximately 1mm into the wood. For dowel joints, the nuts on the bolts must be tightened again several months after installation, so that their tightening effect remains even after the wood shrinks. They talk about a connection with constant force transmission.

Load-bearing dowel connections

Load-bearing dowel (nail) connections have the task of transmitting tensile and compressive forces. With the help of dowel connections, load-bearing parts can be fastened, for example, for simply supported trusses, as well as structures made of boards and beams. Dowel connections can be made single-cut, double-cut and multi-cut. In this case, the size of the nails must correspond to the thickness of the lumber and the driving depth. In addition, when placing nails, certain distances between them must be maintained. In load-bearing dowel connections, holes should be drilled in advance. The drilled hole should be slightly smaller in diameter than the diameter of the nail. Since this does not cause the wood to crack as much, the nails can be placed closer together in this way. In addition, the load-bearing capacity of the nail joint will be increased, and the thickness of the wood can be reduced.

Single shear dowel connections are used when compressed and stretched rods from boards or beams must be attached to the beams (Fig. 20). In this case, the nails pass through only one connecting seam. They are loaded there perpendicular to the hole shaft and can bend if too much force is applied. Since shear forces also arise in the connecting seam in the body of the nail, this section plane is called the shear plane. In the case of paired connection of plank rods on the planes of the main beam, there are two single-cut dowel connections opposite each other.

Rice. 20. Single-cut dowel connection

At double shear dowel connections the nails pass through the three wooden elements being connected (Fig. 21). The nails have two cutting planes, since they are loaded with the same directional force in both connecting seams. Therefore, the load-bearing capacity of a double-shear loaded nail is twice that of a single-shear nail. To prevent double-cut dowel joints from coming apart, half the nails are driven in on one side and the other half on the other. Double-shear dowel connections are mainly used if simply supported trusses consist entirely or predominantly of boards or beams.

Rice. 21. Double-cut dowel connection

Minimum thicknesses of wooden elements and minimum nailing depth

Since thin wooden elements easily split when hammering nails, the boards for load-bearing rods, belts and planks must be at least 24 mm thick. When using nails from size 42/110, use even larger ones minimum thicknessA(Fig. 22). They depend on the diameter of the nail. With dowel joints with pre-drilled holes, the minimum thickness of wood will be less than with simple nailing, since there is less risk of cracking.

Rice. 22. Minimum thickness and driving depth

The distance of the nail tip from the closest cutting plane is called the driving depth. s(see Fig. 22). It depends on the diameter of the nail dn and has a different value for single-cut and double-cut nail connections. Single shear loaded nails must have a driving depth of at least 12dn. However, for certain special nails, due to the greater holding force due to the special profiling, a driving depth of 8d n is sufficient. For double-shear connections, a driving depth of 8d n is also sufficient. With a shallower driving depth, the load-bearing capacity of the nails decreases. If nails have a driving depth of less than half the required, then they cannot be taken into account for the transmission of forces.

Minimum distances between nails

Fastening of formwork, slats and fillies, as well as rafters, lathing, etc. acceptable using less than four nails. However, in general, a minimum of four nails are required for each seam or multiple nail joint intended to transmit forces.

The uniform arrangement of these nails on the connection plane is done using nail marks(Fig. 23). To ensure that two nails located one behind the other do not sit on the same fiber, they are shifted relative to the point of intersection of mutually perpendicular nail marks by the thickness of the nail in both directions. In addition, minimum distances must be maintained. They depend on whether the direction of force is parallel or across the fibers. Next, it is necessary to monitor whether the ends of the rods or the edges of the wood will be loaded by the force acting in the connection or not. Since there is a danger of cracking when the ends of the rods or edges are loaded, it is necessary to maintain large distances from the edges to the nails.

Rice. 23. Minimum distances between nails for a single-cut connection

At single shear nail connection vertical or diagonal stretched rod with nails with a diameter d n ≤ 4.2 mm, the minimum distances shown in Fig. 23. When using nails with a diameter d n > 4.2 mm, these distances should be increased slightly. If nail holes are pre-drilled, shorter distances are required in most cases.

At double shear nail connections the nails are arranged in ledges. Between the risks of a single-shear nail connection, additional risks are drawn with a minimum distance of 10d n (Fig. 24).

Rice. 24. Minimum distances between nails for a double-cut connection

Installation of nail connections

When making nail connections, the nails must be driven vertically into the wood. In this case, the nail head should only be slightly pressed into the wood so that the wood fibers at the joint are not damaged. For the same reason, the protruding ends of the nails can only be bent in a special way. This should only occur perpendicular to the grain. To apply the location of nails, as a rule, appropriately drilled templates made of thin plywood or tin are used. In the case of plywood templates, the holes are made of such a diameter that the nail heads can pass through them. In the case of templates made of tin, the locations of the nails are marked with a brush and paint.

Nail connections with steel plates

Nail connections with steel plates can be divided into three types, namely connections with embedded or externally lying plates with a thickness of at least 2 mm and connections with embedded plates with a thickness of less than 2 mm.

Externally lying pads, as a rule, have pre-drilled holes (Fig. 25). They are placed over the joint of beams or boards at the end and nailed with the appropriate number of wire or special nails. At embedded overlays with a thickness of at least 2 mm nail holes must be drilled simultaneously in the wood members and in the trims. In this case, the diameter of the holes must correspond to the diameter of the nail. Embedded overlays with thickness less than 2 mm, of which there may be several at the joint, can be pierced with nails without pre-drilling (Fig. 26). Such connections can only be made using specially designed spline tools and only with special approval from the authorities.

Rice. 25. Connection using a perforated steel plate-plate

Rice. 26. Nail connection with embedded steel plates (Greim)

Connections using nail gussets

Nail molds are used for rational production wooden half-timbered trusses made from single-row sections of wood (Fig. 27). To do this, wooden rods of equal thickness are cut to length, impregnated and adjusted exactly to each other.

Rice. 27. Connection using a nail gusset

The moisture content of the wood should not exceed 20%, and the difference in thickness should not be more than 1 mm. In addition, the rods should not have any cuts or edges.

The nail gussets must be positioned symmetrically on both sides and, using a suitable press, pressed into the wood so that the nails sit in the wood to their full length. Driving nail heads using a hammer or the like is not permitted.

Fastening with nail gussets creates a connection or joints that are strong in compression, tension and shear at nodal points without weakening the load-bearing section of the wood. For the transmission of forces, the main importance is the working area of ​​the connection of the nail gusset (Fig. 28). It corresponds to the area of ​​contact of the nail gusset with the wood, with the exception of the edge strip with a width of at least 10 mm.

Rice. 28. Working area of ​​the connection at the nail gusset

Trusses with gusseted rods are industrially manufactured only by licensed enterprises, delivered ready-made to the construction site and installed there.