The toughest joiners and carpenters are said to be able to build a house without a single nail. Japanese artisans, even amateurs, are just one of those.

A few years ago, a young automotive industry worker, enthusiastic, fell into the hands of a book describing traditional Japanese woodworking techniques. He was very fascinated by the descriptions of the connections of parts without the use of nails, screws and glue. He wanted to learn how to do the same. But there were no schemes for making fasteners in the book. Then the guy decided to draw them himself.

He used the free service Fusion-360 to model and animate the 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 different ways of detachable connections.

The variety of fasteners is really 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 arms and a good, preferably an electric tool.

But even if manual labor doesn't inspire you at all, you'll probably enjoy watching GIFs. The way the details interlock with each other is mesmerizing.

All photos from the article

Sometimes, when carrying out construction and other work using wood, it is required to make elements longer or wider, and very few people know how to do this correctly. That is why we will consider how to splice the board yourself and what methods and techniques exist. It is important to choose the option that is best suited in a given situation and will require minimal time and money.

Basic workflow requirements

Before we begin to consider specific options for carrying out work, it is necessary to understand what factors are observed to ensure that the result that is expected is obtained:

Material quality	Everything is simple here: it is impossible to make durable structures out of low-quality wood, especially when it comes to joints, if they have knots, damage by woodworms, mold and other problems, then there can be no question of any reliability and durability. Choose the best elements so as not to waste your energy and money in vain
Humidity	Another most important parameter that should always be taken into account. Only dry elements are suitable for work, since high humidity, firstly, reduces strength, secondly, reduces the adhesion of the adhesive composition when it is used, and thirdly, after completion of work, no one will guarantee that in a week or a month the structure will will not lead or it will not crack
Connection loads	It is on this indicator that the choice of one or another connection option largely depends, the greater the load, the higher the requirements for the quality of the pairing and the more difficult the process. Therefore, decide in advance which option will be used in order to guarantee a high result.
Using a quality tool	A lot also depends on this, especially when it comes to complex options, when the connection is cut with special tools. They must provide maximum cutting quality and maximum docking accuracy, since reliability largely depends on this.

Important!
Remember one simple rule that experts always use: to obtain the best result, it is necessary that the parameters of the elements to be joined be similar, in other words, one type of wood should be used.

Work options

All events of this kind can be divided into two large groups - rallying boards in width and length, we will consider them separately and tell you which methods are the most popular and how to implement them correctly.

Width connection

Of course, the simplest solution would be a shield splicing option, so we will start with it, first we will present a diagram of the main options, and below we will describe them in detail:

• The first method involves cutting a cavity with a milling machine, which has a trapezoidal shape and allows the use of a key as a retainer.. The advantage of this solution can be called reliability, and the disadvantage is the need for a milling machine or the availability manual router for work, you can’t get by with a hand tool;
• Rallying using an end bar, which is connected to the ends of the board using the tongue-and-groove method, is used for elements of small length, since this option provides high reliability of precisely small structures. Again, you will need to work. With his help, it will be carried out quickly and efficiently;
• You can make a cutout on the end, fit the rail under it and put it on wood glue, this is also a rather interesting option that is suitable for small structures;
• The last two options involve gluing a triangular rail, only one of them cuts into the end, and the second option involves cutting the end at an angle, you need to choose what better fit in one situation or another.

But if you want to connect the board more securely, then one of the following methods will do:

• The first option is called the connection to a smooth fugue, when it is performed, very careful grinding of the ends is required for a snug fit, after which they are lubricated with glue and connected under pressure or using special ties. This solution is suitable in cases where high bearing capacity is not needed;

• The traditional groove-ridge option is often used, here it is important to ensure the optimal connection configuration, so the width of the groove and, accordingly, the tongue should not be more than a third of the total thickness of the board, it is important to cut very accurately so that the elements match perfectly, this will significantly increase the strength of the connection;

Important!
When working, a milling cutter is most often used, but the cutters can have a different configuration, you should monitor the condition of their cutting edges and sharpen or replace them in a timely manner, since the quality of the connection largely depends on the purity of the processing.

• You can use the option of cutting at an angle, it is well suited where special strength is not required, but you need to connect elements that can be used for finishing, etc .;
• The triangular thorn-groove in many respects resembles the usual one, only the configuration of the ends differs. It is also important here that the elements fit perfectly with each other, as this will ensure both the accuracy of the pairing and its maximum reliability;
• The connection in a quarter is simple - cuts are made for half the thickness, the length of the protrusions should not greatly exceed the thickness, the elements are lubricated with glue and compressed until the composition dries, this standard procedure for almost all options;
• The last view - keyway, it does not differ from the above option when working in width, the requirements are the same.

Conclusion

Connecting the board correctly and securely means ensuring its maximum strength, it is important to follow all the recommendations and use only quality materials. The video in this article will show some of the options for carrying out the work clearly, and if you have questions or an addition, unsubscribe in the comments.

In addition to processing solid pieces of wood, it is often necessary to connect wooden parts into knots and structures. Connections of elements of wooden structures are called landings. Joints in the construction of wooden parts are defined by five types of fits: tense, tight, sliding, loose and very loose fit.

Knots - these are parts of structures at the junction of parts. Connections of wooden structures are divided into types: end, side, corner T-shaped, cross-shaped, corner L-shaped and box corner connections.

Joiner connections have more than 200 options. Only connections used in practice by joiners and carpenters are considered here.

End connection (building) - the connection of parts along the length, when one element is a continuation of another. Such joints are smooth, jagged with spikes. Additionally, they are fixed with glue, screws, overlays. Horizontal end connections withstand compressive, tensile and bending loads (fig. 1 - 5). Lumber is increased in length, forming vertical and horizontal jagged joints (wedge lock) at the ends (Fig. 6). Such joints do not need to be under pressure during the entire bonding process, since significant frictional forces act here. Gear joints of sawn timber, made by milling, meet the first class of accuracy.

Joints of wooden structures must be made carefully, in accordance with the three accuracy classes. The first class is for measuring tool High Quality, the second class - for furniture production, and the third - for building parts, agricultural implements and containers. The lateral connection of several boards or battens with an edge is called rallying (Fig. 7). Such connections are used in the construction of floors, gates, carpentry doors, etc. Plank, rack panels are additionally reinforced with crossbars and tips. When sheathing ceilings, walls, the upper boards overlap the lower ones by 1/5 - 1/4 of the width. The outer walls are sheathed with horizontally laid overlapping boards (Fig. 7, g). The upper board overlaps the lower one by 1/5 - 1/4 of the width, which ensures the removal of atmospheric precipitation. The connection of the end of the part with the middle part of the other forms a T-shaped connection of the parts. Such compounds have a large number of variants, two of which are shown in Fig. 8. These connections (knitting) are used when pairing the log of ceilings and partitions with the harness of the house. The connection of parts at a right or oblique angle is called a cruciform connection. Such a connection has one or two grooves (Fig. 3.9). Cross-shaped connections are used in the construction of roofs and trusses.

Rice. 1. End connections of the bars, resisting compression: a - with a straight half-wood overlay; b - with an oblique overlay (on the "mustache"); c - with a straight half-wood overlay with a joint in an obtuse angle; g - with an oblique overlay with a joint into a spike.

Rice. 2. End connections of the bars (extension), resisting stretching: a - in a straight overhead lock; b - in an oblique laid on lock; c - with a straight overlay half a tree with a joint in an oblique spike (in a dovetail).

Rice. 3. End connections of beams that resist bending: a - with a straight half-wood overlay with an oblique joint; b - with a straight overlay half a tree with a stepped joint; in - in an oblique laid on lock with wedges and with a joint in a thorn.

Rice. 4. Splicing with a notch reinforced with wedges and bolts.

Rice. 5. End connections of the bars, working in compression: a - end-to-end with a hidden hollowed-out spike; b - end-to-end with a hidden plug-in spike; c - with a straight overlay half a tree (the connection can be reinforced with bolts); mr. straight half-wood overlay with wire fastening; e - with a straight overlay half a tree with fastening with metal clips (clamps); e - with an oblique overlay (on the "mustache") with fastening with metal clips; g - with an oblique overlay and fastening with bolts; h - marking the oblique lining; and - end-to-end with a secret tetrahedral spike.

Rice. Fig. 6. End extensions of the milling scheme for end gluing of workpieces: a - vertical (along the width of the part), toothed (wedge-shaped) connection; b - horizontal (through the thickness of the part), gear (wedge-shaped) connection; c - gear joint milling; g - sawing out a gear connection; e - milling of a gear connection; e - end connection and gluing.

Rice. 7. Rallying boards: a - for a smooth fugue; b - on the plug-in rail; in - in a quarter; d, e, f - into a groove and a crest (with various forms of a groove and a crest); g - overlap; h - with a tip in the groove; and - with a tip in a quarter; to - with overlap.

Rice. 8. T-shaped joints of bars: a - with a hidden oblique spike (in a paw or in a dovetail); b - with a straight stepped overlay.

Rice. 9. Cross connections of bars: a - with a straight overlay half a tree; b - with a direct overlay of incomplete overlap; c - with landing in one nest

The connections of two parts with ends at a right angle are called angular. They have through and non-through spikes, open and in the dark, half-dark overlay, half-tree, etc. (Fig. 10). Corner joints (knitting) are used in window irregular blocks, in greenhouse frame joints, etc. A spike connection in the dark has a spike length of at least half the width of the connected part, and the groove depth is 2–3 mm more than the spike length. This is necessary so that the parts to be joined easily mate with each other, and after gluing, there is room for excess glue in the spike socket. For door frames, an angular tenon connection is used in the dark, and to increase the size of the connected surface, in a semi-darkness. A double or triple tenon increases the strength of the gusset. However, the strength of the connection is determined by the quality of its execution. In furniture production, a variety of corner box joints are widely used (Fig. 11). Of these, the simplest is an open end-to-end spike connection. Before making such a connection, spikes are marked with an awl at one end of the board according to the drawing. By marking the side parts of the spike with a file with fine teeth, a cut is made. Every second cut of the spike is hollowed out with a chisel. For the accuracy of the connection, they first saw through and gouge out the sockets for the spikes in one piece. It is applied to the end of another part and crushed. Then they saw through, gouge and connect the parts, cleaning the connection with a planer, as shown in fig. eleven.

When connecting the parts to the "mustache" (at an angle of 45 °), the angular knitting is fixed steel inserts, as shown in fig. 12. At the same time, make sure that one half of the insert or clamp is included in one part, and the other half is in the other. A wedge-shaped steel plate or ring is placed in the milled grooves of the parts to be joined.

The corners of frames and boxes are connected with a direct open through spike connection (Fig. 3.13, a, b, c). With increased quality requirements (with outer side the spikes are not visible), the corner knitting is performed by an oblique connection in the dark, a groove and a comb, or an oblique connection to the rail, as shown in fig. 13, d, e, f, g and in fig. fourteen.

A box structure with horizontal or vertical transverse elements (shelves, partitions) is connected using corner T-shaped joints shown in fig. fifteen.

In connecting the elements of the upper belt of wooden trusses with the lower one, corner cuts are used. When mating the truss elements at an angle of 45 ° or less, one cut is made in the lower element (puff) (Fig. 16, a), at an angle of more than 45 ° - two cuts (Fig. 16.6). In both cases, the end cut (cut) is perpendicular to the direction of the acting forces.

Additionally, the nodes are fixed with a bolt with a washer and a nut, less often with brackets. The log walls of the house (log house) from horizontally laid logs in the corners are connected with a cut “in the paw”. It can be simple or with an additional spike (shank with a pit). The marking of the cut is performed as follows: the end of the log is hewn into a square, to the length of the side of the square (along the log), so that after processing a cube is obtained. The sides of a cube are divided by 8 equal parts. Then, 4/8 part is removed from one side from below and from above, and the remaining sides are performed, as shown in Fig. 17. Templates are used to speed up the marking and the accuracy of making cuts.

Rice. 10. Corner end connections of blanks at a right angle: a - with a single opening through a spike; b - with a single through hidden spike (in the dark); in-with single deaf (non-through) thorn in the dark; g - with a single through semi-secret spike (in semi-darkness); d - with a single deaf spike in semi-darkness; e - with a triple open through spike; g - in a straight overlay half a tree; h - in a through dovetail; and - in eyelets with undercutting.

Rice. 11. Box corner joints with straight through spikes: a - sawing tenon grooves; b - marking the spikes with an awl; in - connection of a thorn with a groove; g - processing by a planer of a corner joint.

Rice. 12. Corner end connections at a right angle, reinforced with metal inserts - buttons: a - 8-shaped insert; b- wedge-shaped plate; in rings.

Rice. 13. Box corner joints at a right angle: a - straight open through spikes; b - oblique open through spikes; in - open through dovetail spikes; g - groove on the plug-in rail end-to-end; d - in the groove and crest; e - on plug-in spikes; g - on spikes in a dovetail in semi-darkness.

Rice. 14. Oblique (on the "mustache") box connections at a right angle: a - oblique spikes in the dark; b - oblique connection on a plug-in rail; in - oblique connection on spikes in the dark; g - an oblique connection, reinforced with a trihedral rail on glue.

Rice. 15. Direct and oblique connections of blanks: a - on a double connection in an oblique groove and ridge; b - on a straight groove and comb; in - on a trihedral groove and a crest; g - on a straight groove and a comb in the dark; d - on straight through spikes; e - on round plug-in spikes in the dark; g - on a spike in a dovetail; h - on the groove and the crest, reinforced with nails.

Rice. 16. Nodes in farm elements.

Rice. 17. Conjugation of the logs of the walls of the log house: a - a simple paw; b - a paw with a wind spike; c - paw markings; 1 - wind spike (pit)

Chiselling and cutting wood

In the simplest connection of wooden parts, a spike and a socket are involved. Nests for spikes, as well as eyes, are made by slotting along the markings. For chiseling use a chisel and chisels. Rectangular nests are hollowed out with chisels, and nests in narrow and thin parts are selected with chisels, spikes and nests are cleaned, joints are adjusted, and chamfers are cut. In addition, chisels are used for processing curved surfaces in cases where this cannot be done with another tool, such as a planer.

Chisel (Fig. 1) are carpentry and joinery. Chisel handles are made from dry hardwood: beech, hornbeam, maple, ash, etc. The tool must be sharply sharpened; chipping on the blade is not allowed. In the case of a through nest, the workpiece is marked on both sides (Fig. 2, a), in the case of a non-through nest, on one side (Fig. 2, b). A through nest is first selected on one side of the workpiece, then on the other.

The chisel is selected according to the width of the socket. For convenience, identical nests are sometimes selected simultaneously in several parts stacked in a pile. The chisel for work is placed with a chamfer inside the nest, stepping back from the marking line by 1 ... 2 mm (Fig. 2, c). This is necessary for cleaning the nest with a chisel. During operation, the chisel is held perpendicular. After the first blow on the chisel placed across the fibers, the fibers are cut, after the second blow on the chisel placed inside the socket, the chips are separated (Fig. 2, d).

Rice. 1. Chisel: a - carpentry (blade width - 16, 20, 25 mm); b - carpentry (blade width - 6, 8, 10, 12, 16, 20 mm).

Rice. 2. Chiseling nests with a chisel: a - through nest; b - blind nest; c - bit position; g - chiseling reception.

Rice. 3. Mallets: a - round; b - prismatic.

Rice. 4. Using the stop when chiselling: 1 - clamp; 2 - detail; 3 - metal stop; 4 - chisel.

Rice. 5. Chisels: a - flat (blade width - 4, 6, 8, 10, 12, 16, 20, 25, 32, 40, 50 mm); b - semicircular (blade width - 4, 6, 8, 10, 12, 16, 20, 25, 32, 40 mm).

The chips must be cut to the entire depth of the nest - to the cut fibers, otherwise the nest will not work with smooth edges. When chiseling the lugs, when the sides of the nest are sawn, undercutting is performed, i.e., the corners of the lugs are cut for subsequent finishing chiselling.

Mallets, which are used to strike the instrument during chiselling, are round or prismatic (Fig. 3). The material for mallets is the wood of elm, hornbeam, viburnum.

When chiselling a hole in a thick workpiece, it is recommended to use a stop (Fig. 4), which is a metal strip 1–1.5 mm thick, curved at an angle of 90°. Such an emphasis is fixed on the bar with a clamp. In order not to spoil the surface of the part during clamping, a gasket must be placed under the strip.

Chisels (Fig. 5) process nests, edges, grooves and chamfers. Curved surfaces are treated with semicircular chisels, all the rest are flat. Angle of sharpening chisels - 25°.

The methods of working with a chisel are shown in fig. 6. When cutting with a chisel, the thickness of the chips to be removed and the direction of cutting are adjusted with the left hand, and the chisel is advanced with the right hand. In fine details, sockets and eyes are hollowed out with chisels using a mallet; in all other cases, hand pressure is used.

Since the tool has a sharp cutting part, any loss of attention during work inevitably leads to injury, therefore, when working with a chisel, extreme care and knowledge of the basic rules for using it are needed. It is forbidden to cut with a chisel towards yourself, with the emphasis of the part on the chest, with the location of the part on the knees, on the weight and in the direction of the supporting hand.

On sale there are forged chisels with the best cutting qualities, and stamped ones. Semicircular chisels with a small width of the cutting part, as well as cranberry chisels, are usually made by the craftsmen themselves. They are used for picking wood in round nests when performing simple carving work. Such chisels are also found in woodcarving tool kits.

To work, it is enough for a carpenter to have two chisels with a blade 6 and 12 mm wide, as well as a set of chisels with a blade width from 2 to 16 and 25, 40 mm.

A chisel cutting wood meets its resistance. The amount of resistance that the cutter encounters on an area of ​​1 m2 of the cross section of the chip is called specific cutting resistance. When cutting wood, the angles formed by the front and rear faces of the cutter with the processing surface are distinguished (Fig. 8).

The angle between the front and back faces of the cutter is called the sharpening angle. For planer knives and chisels, it is 20 ... 30 ° and depends on the hardness of the material being processed.

The angle between the front face of the cutter and the cutting surface is called the cutting angle. For planing knives of hand tools, it is 45 ... 50 °, and for machine tools - 45 ... 65 °. The surface finish depends on the cutting angle - the larger it is, the smoother the surface. Increasing the cutting angle increases the cutting force. Surface finish depends on tool rotation speed and material feed. In other words, the higher the tool rotation speed and the lower the feed rate, the higher the surface finish. The angle between the back face of the cutter and the cutting surface is called the clearance angle. The value of this angle depends on the angle of sharpening and the angle of cutting.

There are three main cutting options (Fig. 9): across the fibers, along the fibers and cutting to the end. End cutting requires the most effort. Cutting obliquely (at an angle to the direction of the grain) is performed with slanting or curly wood. Cutting along the fibers is 2…2.5 times less than cutting across the fibers.

The cutting force depends not only on the sharpening angle and the cutting angle, but also on the hardness of the wood, the width of the cutter blade, the moisture content of the wood, the cutting direction, the sharpening of the cutter and the friction forces against sawdust and shavings.

Hard wood (oak, beech, ash, pear, etc.), as well as wood with knots, graininess, slant, require a lot of effort during processing. The heterogeneity of the wood structure predetermines the unequal resistance value, depending on the direction of cutting.

The chip shape depends on the cutting direction. When cutting at the end, the chips will turn out in the form of sawdust. When cutting along the fibers, a ribbon-like chip is formed. When cutting wood across the fibers, chips are obtained in the form of small chips, and the treated surface becomes rough.

The dulling of the cutter requires an increase in cutting force. A blunt cutter does not cut, but presses and tears the wood. Due to the blunting of the cutter after 4 hours of work, the cutting force increases by 1.5 times. A dull cutter increases the friction between the cutter and the chips, requiring extra effort and overheating of the cutter.

Wet wood is easier to process than dry wood due to the hardness of the latter. However, the cleanliness of wet wood is lower due to hairiness.

The cleanliness of wood processing depends on the direction of cutting. Cutting along the fibers gives smooth surface. When cutting across the grain, cleanliness is possible with a sharp cutter and very thin chips. The cutter that processes the wood goes deep into it, the chips are separated due to elasticity before the cutter touches, and the surface to be machined has a roughness. This is typical when cutting across the die (Fig. 10, a). To obtain a clean surface treatment, a retaining ruler is placed in front of the cutter. A clean surface can be obtained if the cutter of a planing tool (manual, electrified or machine tool) is supplemented with a chipbreaker (Fig. 10, c, d). It increases the cutting angle, breaks the chips, turning them into a spiral. The thinner the chip thickness, the better the surface finish.

Rice. 9. Cutting wood: a - cutter in open cutting; b - cutter in closed cutting; c - cutting directions; 1 - across the fibers - at the end; 2 - along the fibers; 3 - in the tangential direction; 4 - in the transverse-end direction; 5 - in the longitudinal-end direction; 6 - in the longitudinal-transverse direction.

Rice. 10. Cutting techniques: a - chipping off chips before they are cut; b - cutting with a retaining ruler; c - the use of a chip breaker; d - with increasing cutting angle.

Enlargement of incisors (teeth circular saw, knives on the shaft planer etc.) reduces the thickness of the chips and increases the cleanliness of processing. The quality of processing wood of any species, including the presence of defects (knots, oblique, tortuosity, etc.), is affected by the speed of the cutter. With increasing rotation speed cutting tool chip formation waviness becomes finer, which increases the surface finish. The purity of the processing of individual sections is affected by defects, wood properties, sharpness of cutters, inaccuracies in marking, violation of technology. Deformations of wood caused by its moisture exceed the dimensional deviations allowed in woodworking. Before processing lumber for carpentry and joinery, the moisture content of the wood is checked.

Additional fasteners for carpentry joints

Wooden structures during operation are deformed, their connections become fragile. In such cases, the joints are fixed with wooden dowels, spikes (dowels), wedges and dowels (Fig. 1) from very hard and dry wood (moisture content 4 - 6%).

Wooden nails (pins) made of oak, maple, ash or birch. Before driving the dowel, a hole (through or non-through) of the required diameter is drilled and the dowel edges are rounded. This protects the wood from cracking at the joints (in the corners of window and greenhouse frames, etc.). Wooden spikes (dowels), for example, secure the joints of the rafters to the roof ridge. They are cylindrical, rectangular and square. The lower end of the spike is somewhat pointed. Before driving the stud, a hole is drilled slightly smaller in diameter than the diameter of the stud. Wooden wedges are made from coniferous wood (pine, spruce), one- or two-sided. One-sided wedges have one wide side obliquely hewn, while two-sided wedges have both sides. The sides have a slope of 1:6, 1:7 and 1:8°. With such wedges they strengthen and stretch wooden structures, level the floor logs, raise the settled parts of the walls and roofs. Wedges are used to jam the handles of hand tools (axes and hammers), although metal wedges should be preferred.

Dowels. Composite beams of two or three beams with wooden dowels. The shearing forces between them are perceived by the keys. The elements of the beam are additionally tightened together with steel bolts. Oak dowels are inserted into the slots between the elements of the composite beam. Sockets for dowels are selected with an electric slotter simultaneously in two bars, then the dowels are hammered into the sockets with blows of a wooden hammer. The protruding ends of the dowels are cleaned with a planer. The dowels in the middle of the span of the composite beams are not installed due to the weak load.
Keys in relation to the connected elements are distinguished: longitudinal, transverse, oblique longitudinal and stretched keys (Fig. 2). Transverse dowels (compared to longitudinal dowels) provide a less durable connection, since wood across the grain has less resistance than along the grain.

Composite beams on dowels are made from well-dried wood. If a key is installed in a slot with a gap, then it will not absorb shear forces and the transmitted load will be transferred to other keys. Mechanized production of keys and sockets guarantees the appearance of gaps. The cross section of composite beams should not be weakened by sockets by more than 1/3 of the height of the element. With a symmetrical arrangement on opposite sides of the nests, their depth should not exceed more than 1/6 of the thickness of the element, but not less than 2 cm. Longitudinal dowels and bolts are used to connect the bars (Fig. 2, e). A strong and tight connection is obtained by using two wedge-shaped keys with an interference fit (Fig. 2, d), acting as wedges. The advantages of such keys are that during operation with wedges it is possible to restore the tightness. Doweled joints are used to reinforce floor beams and Derevyagin beams (Fig. 3).

Rice. 1. Installation of plug-in spikes: a - installation of a cylindrical wooden pinch (dowel) on glue; b - tense corner joint on two cylindrical spikes; c - tense corner joint on three rectangular wooden spikes.

Rice. 2. Tightening with bolts of two bars connected by dowels: a - longitudinal dowels; 5 - transverse dowels; h - transverse keys located diagonally; g - wedge-shaped dowels; d - bolts passed through the keys.

Fig 3. Composite beam of the Derevyagin structure: a - front view and cross section; b - a fragment of the location of the dowels in the composite beam.

Making boards from wood

To minimize or prevent warping of panels intended for the manufacture of furniture and for other purposes, the following measures are taken: for the manufacture of shields, only dry wood is used (moisture content - 8-10%); wide boards are sawn into narrower ones, and shields are made with a width of no more than 100 mm; adjacent sections in the shields are arranged so that the annual layers at the ends of the welded blanks are at different angles when connected (it is better if they are directed in opposite directions).

To reduce the warpage of solid wood carpentry panels, constructive measures are also used (Fig. 1): rallying on dowels with tips and tying the shields with a frame with grooves. Best effect gives a way to tie the shields with a frame.

Knitting of solid wood shields is carried out on a comb, dovetail spikes and plug-in round spikes. The easiest way to mark up and perform is knitting on a comb. The dimensions of the spikes are equal to the dimensions of the nest eyes. Knitting on a dovetail spike is used mainly in the manufacture of caskets, caskets, etc. It is complex both in marking and in manufacturing.

The tee knitting of carpentry shields is widespread (Fig. 2). Perform it mainly in the groove and crest. At the same time, the edges are carefully processed, since their exact fit is required. The grooves are arranged by manual rallying; their depth is from 1/3 to 1/2 of the thickness of the shield. The easiest to perform is the connection in a wide groove. The use of shoulders increases the stability of knitting. The greatest rigidity of the structure will be when connected to the award with two shoulders. Perform it mainly without the use of glue. It should be noted that the reward method is used only for knitting shields from an array.

In addition to the basic methods of knitting into knots, parts are also connected with nails, screws and bolts, using metal and wooden squares and an additional bar (Fig. 3).

The wedge-thorn joint on glue is considered very strong. How to make such a connection is shown in Fig. 4. When the spike with the wedge inserted into it reaches the stop at the bottom of the nest, it will wedged and will be firmly held in the nest. The wedge can be made from durable and dry wood (oak, beech, etc.).

How to hammer a nail correctly: First, mark the points and prick them with an awl, keeping an eye on the tilt of the awl, as the nail will go in the direction of the prick. If possible, nail the nail not perpendicular to the plane, but at a slight slope. The connection from this will be more reliable. If the nail is nailed perpendicular to the plane, then it will serve as the axis of rotation and the connection will soon weaken. It is necessary to nail a thin part to a thick one. The diameter of the nail should be no more than 1/4 of the thickness of the part to be punched, and its length should be 2...4 times this thickness. When punching the parts to be joined, bend the tip of the nail. To do this, firmly press a trihedral file against it and bend the hook with hammer blows on the end of the nail. After removing the file, drive the hook into the wood.

To prevent the board from splitting when driving a nail, blunt its tip (or bite off with wire cutters). Such a nail will crush the fibers of the wood, but will not split it.

Rice. one. : a - rallying on the key; b - strapping with a frame with a groove; 1 - shield; 2 - nest; 3 - key; 4 - frame with a groove; 5 - comb.

Rice. 2. : a - in a wide groove; b- in a narrow groove with one shoulder; in - in a narrow groove with two shoulders; g - as a reward with one shoulder; d - as a reward with two shoulders; e - as a reward with flat spikes; g - as a reward with plug-in round spikes.

Rice. 3. : a - a metal square; b - plywood square; in - a wooden bar; g - a coupling bolt.

Rice. 4. : 1 - socket; 2 - wedge; 3 - spike.

When nailing woodwork, remember that a nail hammered along the fibers holds less strength than a nail hammered across them. Several hammered nails placed close together along the same layer can split the board. This will also happen if a thick nail is hammered near the edge. Therefore, for the strength of the connection, hammer in several not very thick nails in two rows, placing them in a checkerboard pattern. If, based on the design of the part, you need to drive a nail at the edge of the edge, then pre-drill a hole for it. The diameter of the hole in this case should be 1/5 - 1/7 less than the diameter of the nail.

To drive a nail at the right angle, especially a small one, stick a piece of plasticine or wax on the place where it should be hammered and stick a nail into it at this angle. After one or two blows with a hammer, the plasticine can be removed.

When nailing a board, hammer nails not parallel to each other, but at a certain angle, and each of them is in different sides. Fastening in this case will be more reliable.
You can hammer a nail in a hard-to-reach place using a metal tube and a rod that freely enters this tube. To do this, put the tube in the place where the nail should be hammered, lower the nail into it, then the rod and hit the rod several times with a hammer. The nail will go into the tree, but unevenly. After removing the rod, align the position of the nail with a tube and then hammer it in according to the “nail - rod - hammer” system. The rod should be 10-15 mm longer than the tube.

If the screw connecting the parts is loose and turns when screwing, it can be strengthened by first inserting a match into the socket; the screw itself must be lubricated with petroleum jelly. It is difficult to screw a screw into chipboard. But you can do it without special efforts if you pre-drill a hole with an electric drill. Fill this hole with glue, put a piece of soft plastic tube into it and screw in the screw. Glue that has penetrated inside the tube will facilitate the screwing process; after drying, it will firmly hold the tube and screw in the socket.

When unscrewing a "stubborn" screw, lightly tap with a hammer on the handle of the screwdriver inserted into its slot. In this case, the screwdriver must be turned with a certain force.

To properly screw a screw into hardwood, prick the screwing point with an awl and sprinkle some soap crumbs there; the screw will be easier to screw. Also, when driving a thick screw, drill a hole with a diameter 1/5 smaller than the diameter of the screw; the depth of the hole must be greater than the length of the screw. With a screw diameter of 2 mm or less, there is no need to drill: it is enough to prick sharp object(awl, scriber, etc.).

How to choose a wooden blank

Wooden blanks, commonly referred to as "linen", come in many different shapes and sizes. They are made mainly from affordable cheap wood species - linden, birch, aspen. The main rule when choosing a blank is the quality of the material and assembly (for glued products). Wood for harvesting (except for solid turned blanks) must be aged - dried, so that after processing and drying the tree does not “drive”, it does not crack or dry out, there should also be no visible severe damage, pronounced burrs, burrs and through holes from knots . The surface must be smooth, not loose or porous.

The assembly quality of glued blanks (caskets, icon boards, complex shapes) affects how the product behaves after processing. If the arrangement of the layers is incorrectly chosen and the parts are poorly fitted, then then gaps may appear at the joints. Do not expect that the crooked box will then “dry out” and level out, as unscrupulous sellers promise, rather the opposite.

For the manufacture of jewelry, wooden buttons, beads, bracelets are needed. For painting, decoupage and decoration - frames, plates, trays, spoons, nesting dolls, dolls, glass holders, cutting boards, caskets, dishes, vases, caskets, mugs, whistles, toys. Ordinary boards are not suitable for icon painting; special boards are needed - icon boards with special inserts against warping.

For carving “Trekhgranka”, “Kudrinka”, “Tatyanka”, all workpieces made of linden are suitable (birch and aspen are more difficult to process with cutters) without knots with a wall thickness of 7-10 mm for low relief and 10-15 mm for high relief. And it is better if the blank is made from wood of 2-3 year old trees, because. it is more homogeneous and dense in its structure. There are blanks only for carving, these are gingerbread boards, forms for Easter.

For light decoupage and light-tinted carving, the workpieces must be without darkening. For painting and decorating, blanks with darkening are primed, so dark knots and “marble” wood coloring will not interfere, as well as shallow dents that can be hidden - they are filled with a mixture of sawdust with PVA before priming (in several layers with intermediate drying) or a mixture for papier -mache (mass is best made from pieces of napkins with glue). In the same way, you can correct a defect in collapsible turned forms (nesting dolls, apples, eggs, pears) when the upper part does not fit tightly and falls off when turned over - to do this, coat the inner edge of the upper half with the mixture and dry it well (if done on the bottom, it will be noticeable and ugly). If the hollow collapsible "tochenka" has dried up unevenly and does not close, then grind upper part from the inside and the outer border of the bottom.

It is necessary to store the blanks before processing in a tightly closed plastic bag in order to maintain their stabilized moisture and prevent drying out, warping or dampness.

Saws and Sawing

Saws and sawing. Saw blades are made of high quality steel with cut teeth. For carpentry and joinery use a wide hacksaw, a hacksaw with a butt, a narrow hacksaw; a saw with a sawing depth limiter (award), a bow saw, as well as a plywood saw (knife) (Fig. 1).

A wide hacksaw is made from steel tape 0.7 m long, 11 cm wide at the handle and 2 ... 7 cm at the narrow end. The handle can be wooden, metal or plastic. A narrow hacksaw is used for cutting curved through holes in large-width parts. The jigsaw (Fig. 2) has a narrow and thin (0.3 mm thick, 1 ... 2 mm wide) file with fine teeth. The file is fixed in an arched frame and can be easily removed. A jigsaw cuts out thin parts (plywood) of a curvilinear shape. Before starting work, the end of the file is inserted into a pre-made hole, and the other end is fixed in the frame. Sawing is carried out according to the markup. At the end of the work, the end of the file is released and removed from the hole in the part.

Hacksaws with a butt are used for shallow sawing, for example, sawing grooves in wide workpieces, for fitting parts during their assembly. The top of the blade is reinforced with a steel butt, which increases the rigidity of the blade. Small teeth have the shape of an isosceles triangle. A hacksaw is sawn in both directions (Fig. 1, c).

According to the shape of the teeth, saws are distinguished for longitudinal, mixed and transverse sawing (Fig. 3).

For sawing along the fibers, saws with oblique teeth are used. They cut wood in one direction - away from themselves. The cavity between the teeth is called the sinus. The pitch of a tooth is the distance between the tops of adjacent teeth. The height of the tooth is equal to the perpendicular drawn from the top of the tooth to its base. There are three edges in the saw tooth (Fig. 3, a). In rip saws, the cutting is performed by the short cutting part - the leading edge, and the side edge only separates the wood fibers.

Rice. one. : a - wide hacksaw: b - the same, narrow; c - backing hacksaw; g - award; d - plywood file.
Rice. 2. Jigsaw.	Rice. 3. : a - saw elements; b - saw tooth angles; I - for longitudinal sawing; II - for mixed sawing; III - for cross sawing: 1 - side cutting edges; 2 - front face; 3 - front cutting edge; 4 - step; 5 - top; 6 - sinus; 7 - height; 8 - line of the base of the teeth.

For longitudinal and transverse sawing, a bow saw is used. It consists of a beam frame with a stretched saw blade. The latter is made of a steel tape about 1 m long, 45 ... 60 wide and 0.4 ... 0.7 mm thick. Tooth pitch 4…5 mm, tooth height 5…6 mm. The ends of the saw blade are fixed at the bottom of the racks of the beam frame. The canvas is stretched with a bowstring made of twine, fixed between the upper ends of the uprights and the twist. The rotation of the saw blade is carried out with the help of handles. This saw can be operated by one person. The cut is smooth and even. The teeth of crosscut saws cut the fibers, the side edges of the teeth, and the leading edge only separates them. In rip saws, the leading edge of the tooth cuts the wood. This is taken into account when determining the sharpening angles of the teeth of saws for transverse and longitudinal sawing.

Rice. 4. Sawing along the fibers with a bow saw if the material is in a horizontal position: to the right - the position of the feet of the worker during sawing.
Rice. 5. Stands: a - wooden with a movable support: b - metal with a roller; in - wooden with a roller.	Rice. Fig. 6. Sawing with a bow saw along the fibers with vertical fixing of the material: a - the position of the worker's hands during sawing; b - the same, feet.	Rice. 7. Cross sawing: a - sawing techniques; b - hand support of the sawn off part at the end of sawing.

For saws for longitudinal sawing of soft wood, the sharpening angle is 40 ... 45 °, for saws for hard wood - up to 70 °, in saws for transverse sawing, the angle between the cutting edges of the teeth is 60 ... 70 °, and the sharpening angle is 45 ... 80 °. For saws for mixed sawing, the sharpening angle is 50 ... 60 °. The saw tooth angles are as follows: for longitudinal sawing - 60 ... 80 °, for transverse sawing - 90 -120 °, for mixed sawing - 90 °. To regulate the depth of cut, it has a movable stop. Saw blade thickness 0.4 ... 0.7 mm, length -100 ... 120 mm.

Types and methods of sawing. According to the type of fastening of the part in the workbench, there are: horizontal sawing along the fibers, vertical sawing along the fibers, horizontal sawing across the fibers and sawing at an angle. When sawing horizontally along the fibers, the workpiece is fixed by pressing it to the table with clamps (Fig. 4) so ​​that the sawn off part protrudes beyond the edge of the workbench. In this case, the worker's body should be slightly tilted forward, the saw should be held vertically. First, they make a drink by moving the saw several times up, after the drink becomes deep, they start sawing by moving the saw up and down. A wedge inserted into the kerf prevents the saw blade from pinching.

When sawing vertically along the fibers, the workpiece is fixed in the workbench with a front or rear clamp (Fig. 6). The figure shows the position of the worker's legs during the sawing process. When sawing a thin board, it is clamped so that it does not bend, lifting it up as it cuts. Sawing begins with a gash, after which they work at the full swing of the saw blade without pressing it. Short workpieces are sawn starting from one end, and then, turning the workpiece over, from the other. Sawing long boards (along the fibers) is performed by resting their ends on stands (see Fig. 5).

Rice. eight. : a - correct; b - incorrect (cutting angle is too large); c - splintered cut, due to improper sawing, flakes and damage to the edges are possible; g - sawing along the fibers with a hacksaw; e - sawing with a bow saw using a template (miter box); e - sawing with a narrow hacksaw through drilled holes; g - a template for trimming the ends of boards stacked in packages; 1 and 2 - side racks - guides for the saw; 3 - board attached to the racks; 4 - fixing the nail of the auxiliary device; detail A - the position of the hand on the frame of the bow saw during sawing.

Sawing the workpiece across the fibers, the end to be sawn off is extended beyond the edge of the workbench (Fig. 7). Before sawing, a saw is made, while sawing, the position and inclination of the saw blade is monitored so that the cut is straight and the sawn surface is even.

To avoid flaking, the sawn off part of the workpiece (Fig. 7, b) at the end of sawing should be supported by hand. For spiked joints or other parts that require mating at an angle of 45 or 90 °, use a template (miter box) (Fig. 8, e). With repeated use, the cuts on the wall of the miter box can become excessively wide and it will not give an accurate angle size. To extend the durability of the miter box, its side walls are made of hardwood boards. For trimming boards (of the same width), a special template is used (Fig. 8, jar). The side posts of the template serve as guides for the saw, they are made of solid wood. For boards of a certain width, an individual template is required. Sawing wood by hand is acceptable for small amounts of work.

Preparing the saw for work

Saw preparation includes jointing, breeding and sharpening of teeth. The nature of the saw blade is affected by the shape, size and inclination of the teeth. Saws with isosceles teeth are recommended to be used only for transverse sawing, rectangular saws - for longitudinal and transverse saws, with inclined teeth - only for longitudinal sawing.

Jointing saw (Fig. 1) is to align the tops of the teeth so that they are at the same height. To do this, a file is fixed in a vice and the tops of the teeth are moved along it. The quality of jointing is checked by attaching a ruler to the tops; at the same time, there should be no gaps between the tops of the teeth and the edges of the ruler.

Setting . So that the saw blade is not clamped in the cut, the saw teeth are bred, that is, they are bent: even - in one direction, odd - in the other. In this case, not the entire tooth is bent, but only its upper part (1/3 from the top of the tooth). When breeding teeth, it is necessary to observe the symmetry of the limbs on both sides. For sawing hard rock the teeth are bred by 0.25 ... 0.5 mm per side, soft rocks - by 0.5 ... 0.7 mm.

Rice. 2. Universal wiring: 1 - plate; 2 - adjusting screws; 3 - a scale showing the magnitude of the divorce; 4 - screw with stop, adjusting the height of the bent tooth; 5 - spring; 6 - lever for bending the tooth from the saw.	Rice. 3. A template for checking the correctness of the saw teeth setting: 1 - saw; 2 - template.

When sawing raw wood, the divorce should be maximum, and when sawing dry wood, it should be 1.5 times the thickness of the saw blade. The width of the cut should not exceed twice the thickness of the blade.

For dilution of the saw, it is recommended for a novice carpenter to use a special wiring (Fig. 2). The correctness of the saw's divorce is checked with a template (Fig. 3), moving it along the blade. The saw is bred evenly, without applying much effort, otherwise you can break the tooth.

The teeth are sharpened with files having the shape of a rhombus or a triangle, with a double or single notch. Before sharpening, the saw is securely fixed in a vise on a workbench. The file is pressed against the tooth when moving away from you; when returning, it is slightly raised so that it does not touch the saw. The file should not be pressed too hard against the tooth, as this will heat up the file, which will lead to a decrease in the strength of the teeth.

The teeth of saws for longitudinal cutting are sharpened on one side and the file is held perpendicular to the blade. For transverse cutting, the teeth are sharpened through one and the file is held at an angle of 60 ... 70 °. Bow saws are sharpened with a trihedral file.

Saws with a large tooth are bred and sharpened, and with a small one they are mainly sharpened, but not bred. This is explained by the fact that in carpentry work completely dry material is used, the blade of bow saws is thin (0.5 ... 3 mm is very difficult to breed. The cleanliness of work of sharpened, but not divorced saws with a stretched blade is much higher than one-handed hacksaws with a divorce, which is especially important when sawing spikes and eyes.

Bow saw work

To work with a bow saw, it is necessary to correctly install the blade in relation to the machine. Its angle of inclination should be 30 °; the correctness of rotation is adjusted by the handle. The saw blade must be straight, not skewed and well taut. They saw slowly, but with confident movements; in a hurry, the cut is uneven.

A quality bow saw in working condition should be difficult to turn the handles. After work, it is recommended to loosen the twist so as not to subject the rack to loads and not to stretch the canvas.

When ripping, the material to be sawn must hang outwards. With transverse sawing (Fig. 1, a), the workpiece lies horizontally, with longitudinal sawing (Fig. 1, b), it can be in horizontal and vertical positions. Usually start sawing from the nail thumb left hand (Fig. 2), so this technique is called "on the nail." When sawing, the marking line must be visible at all times. For accurate transverse cutting of the board, a miter box (shtosslad) is used, which is a box in the side walls of which there are cuts made at a certain angle (Fig. 3).

Rice. 1. Cutting the boards with a bow saw: a - transverse; b - longitudinal.

Sawing along the fibers with a bow saw if the material is in a horizontal position: to the right - the position of the feet of the worker during sawing

For sawing wood with cross-layer, knots and other defects, a bow saw with a thickened and wider (up to 50 mm) blade is used. A circle saw that has a narrow blade (up to 8 mm), rectangular teeth and a large divorce (2 - 2.5 thicknesses blades), as well as high machine stands, it is possible to perform curved sawing without much effort, since a large blade spread gives a wide cut in which the blade can easily be turned in the required direction.

When sharpening a bow saw in a vise, the file may slip and injure your hand. Yes, and holding on to the sharp edge of the file is not very convenient. To insure yourself against possible injury, put on the file head a tip made of a rubber tube (length - 3 ... 4 cm), cut along the length on one side.

After buying a bow saw, carpenters sometimes shorten the mullion, change the bowstring, make wider bow stands, since shortened machines are easy to use, wider stands reduce their deflection when the bowstring is pulled, and with a bowstring thickness of 10 mm, an even and strong tension is obtained and it is eliminated gap. The bowstring at the junction with the uprights is usually wrapped with fishing line at a distance of 25 ... 30 mm from the uprights. At the same time, in the event of a breakage of the twist, the bowstring does not fall off the machine.

For convenience, additionally clean the handles in the bow saw with fine-grained sandpaper and cover the entire machine with oil varnish.

To tension the bow saw, it is advisable to use a lever bowstring instead of a twisting one (Fig. 4). It is easy to make such a bowstring from two pieces of cable with a diameter of 2 ... 3 mm. The device uses a metal lever, the end of which is bent and inserted into the hole in the mullion. The degree of tension depends on the position of the hole into which the lever enters. It takes seconds to loosen or tighten the tension on the saw blade. In addition, the cable is an "eternal" bowstring. The mullion can be made of wood, for which you need to choose a hard rock (for example, beech).

To reduce the friction of the bow saw blade against the walls of the cut, its thickness should be reduced. To do this, attach the canvas horizontally with a clamp to a metal base. At a distance 4 ... 1 times the width of the blade, fix a metal plate on the base with a thickness 5 times the thickness of the saw (Fig. 5). Then with a file with a large notch, resting its end on a metal plate, remove a layer of metal from the saw. Do the same operation on the other side of the saw. After removing the metal, sand the canvas with fine-grained sandpaper.

Rice. 4. Tension device for bow saw: 1 - rack; 2 - cable; 3 - lever; 4 - middle.

Rice. 5. Reducing the thickness of the bow saw: 1 - saw blade; 2- metal base; 3 - a plate placed to form a thinning angle; 4 - file; 5 - clamp.

Modern bow saw It is a metal tube (or rod) bent by an arc, between the ends of which a cutting blade is stretched. A rigid arc allows you to make the cutting blade thin, long, narrow. Depending on the size of the arc, a blade with a large tooth (4 - 5 mm high) can be from 30 to 90 cm long. The cutting blade is attached with bolts, pins or an eccentric bracket, which makes it easy to adjust the degree of its tension.

The fastening of the cutting blade in some bow saws is carried out by means of swivel couplings. They make it possible to rotate the plane of the blade relative to the plane of the saw itself. At the beginning of the cut, the saw should be held so firmly that the force of the brush is significantly greater than the weight of the saw. At the same time, the hand quickly gets tired, but the cut will turn out to be even.

Another simple rule: the teeth of a bow saw should cut into the wood due to the weight of the saw itself. If you try to apply force, a thin and narrow cutting blade will begin to “play”, which will greatly complicate the process itself. All bow saws, the arc of which is made of a metal tube, have plastic, metal or wooden handles of various configurations and are intended only for work directly by hand.

Lumber marking

Wood is marked out so that as little waste as possible is obtained from the lumber used for blanks for parts. In other words, marking is necessary to obtain a workpiece with a minimum allowance for processing with a hand or electrified tool. To mark and check the accuracy of processing workpieces and parts, many special and universal devices are used. For a novice carpenter, at the beginning of mastering carpentry skills, the following tool is needed (Fig. 1):

• 5-meter tape measure - for linear measurements and rough marking of lumber;
• square - to check the angle of 90 °;
• folding rule - for any measurements in width and thickness;
• malka - for measuring and measuring angles; level - to check the horizontal and vertical arrangement of surfaces;
• compasses - for transferring dimensions to workpieces and for marking circles;
• thickness gauge - for drawing risks parallel to one of the sides of the bar or part;
• plumb line - to check the verticality of wooden structures.

Marking lines are applied with a pencil, and on a clean planed surface with an awl. On boards and other long materials, the lines are applied with a cord-chopping, and on light details it should be beaten off with charcoal, on dark ones - with chalk.

Rice. one. 1 - tape measure, 2 - square; 3 - folding rule; 4 - small; 5 - level; 6 - compass; 7 - thickness gauge; 8 - plumb; 9 - awl.

Rice. 2. a - for marking spikes; b - for marking in the "dovetail"; 1 - scriber; 2 - blank; 3 - template.

Rice. 3. 1 - handle; 2 - roulette; 3 - window for setting the required radius; 4 - body; 5 - scriber (knife); 6 - clamping bar; 7 - fastening screw; 8 - installation needle.

Marking lines are recommended to be applied with a simple pencil with a hardness of T or TM. Colored pencils have a soft lead and break quickly; the lines applied with an indelible pencil, when the surface is wetted, are inevitably blurred, as a result of which the material is contaminated.

On a metal ruler, the division scale is often erased. To avoid this, paint the acetone-treated canvas of the ruler with white or red nitro paint, then wipe the ruler with a cloth. The paint will be removed from the canvas of the ruler, and the numbers and marks will remain in the recesses. So you get a clear scale of divisions. For faster and more accurate marking, it is recommended to use templates (Fig. 2), which are metal or metal of various sizes and shapes. wooden blanks with the exact dimensions printed on them. You can make these templates yourself.

There are cases when it is necessary to mark a large circle. This is usually associated with certain inconveniences. The fixture shown in fig. 3, simple in design and easy to handle. Its main advantage is the ability to mark a circle of any diameter. It can be seen from the figure that the longer the metal sheet of the tape measure, the greater the radius of the structure to be marked. When replacing the scriber (or pencil) with a cutter, you will get a compass cutter.

AT carpentry wooden and metal squares are used for marking. Before marking, a new wooden square is checked for accuracy by attaching its outer corner to the outer corner of a metal square. The protrusions found at the wooden square are rubbed with cloth-based sandpaper. To check the inner corner, the wooden square is applied with this corner to the outer corner of the metal square, and carbon paper is placed between the contacting surfaces, which will paint the protruding irregularities of the inner corner. Then these irregularities are rubbed with a medium grit sandpaper.

Manual planing

Manual planing tool. The main tool for hand planing is a planer. All modifications of the planer (sherhebel, planer with a single and double knife, jointer) have a fundamentally the same device (Fig. 1); they differ mainly in the thickness of the removed layer of wood and the cleanliness of the surface treatment of the workpiece. So, if the planer is rough planing (the thickness of the layer being removed is 2 ... 3 mm), then the jointer completes the leveling of the surface (chip thickness is up to 1 mm).

Scherhebel is used for roughing wood across, along the fibers and at an angle to them (the chips are narrow and thick - up to 3 mm). With a planer with a single knife, the surface is leveled after sawing and applying a sherhebel. More convenient in terms of surface frequency is a planer with a double knife, which has a chipbreaker that eliminates surface defects - scuffs and chips. In addition to wooden tools, metal shearhebels and planers with a single and double knife are used mainly for repair work in an apartment setting. Jointer performs surface finishing. It has a long block, which, when planing long parts, has a positive effect on the quality of the surface to be treated. A jointer is planed until a clean and even chip goes.

A tool with a wooden block is used for basic work, and with a metal sole and body - in cases where the wooden surface of the tool can be damaged (planing of hard ends, chipboard and non-wood materials - plastic, plexiglass, ebonite, hardboard, etc.). In the process of work, a wooden tool gives less stress on the hands, which means less fatigue. In addition, the friction of such a tool is low, its sliding on the surface is better than that of a metal one.

In carpentry, sometimes it becomes necessary to plan small and narrow parts. Ordinary carpentry tools are too large for this, and small planers are suitable for such work.

In addition to tools that make it possible to process products by plane planing, special tools are also used for shaped processing of recesses and edges (Fig. 2).

The selector serves for selecting quarters in rectangular parts and processing edges. Falzgebel is similar to a selector, but its sole has a stepped structure. It serves to select quarters, which are then cleaned with a zenzubel.

Zenzubel is used to select longitudinal recesses in the form of right angles (folds) on the edges of parts. The blade of such a zenzubel is straight and forms a right angle with the side edge of the piece of iron. A zenzubel with an oblique piece of iron is used for stripping folds planed with another tool. Such a zentub should not be confused with a helical zentub, which is used to process dovetail profiles.

The grooving tool is used for selecting narrow grooves (tongues) and quarters in a rectangular part, and the grooving tool is used for ridges and grooves on the edges of parts.

With a stamp, roundings are arranged on the edges of the parts; its block and knife have a concave rounded surface. Kalevka perform curly processing of the front edges of the parts. The fillet serves to select grooves in the details. Humpback handle concave and convex surfaces.

When buying wooden blocks, pay attention to a sufficient allowance on the shoulders, to which the wedge is pressed from below, and the distance from the edge of the gap to the end of the knife (in assembled it should not exceed 2 mm). Usually after purchase, wooden blocks are kept in room temperature about three months. In addition, wooden blocks are adjusted “under the arm”, removing scuffs, dulling the ribs, grinding the walls and covering the sides and top with oil varnish. The notch of any tool should not have chips and scuffs.

Tool setting. The set-up work includes disassembly and assembly of the tool, as well as replacement and fastening of the knife. To disassemble the planer, it is enough to hit the tail end lightly with a hammer, and to assemble it, you need to lay the knife and hit the front end. Consequently, the overhang of the knife will increase when hitting the front end and decrease when hitting the tail end. To the horizontal plane, the knife is set at a certain angle. For the main planing operations for a sherhebel, planers with a single and double knife, this angle is 45 ° for a zenzubel, and 80 ° for a tsinubel. The jointer knife is taken out by hitting its cork.

The blade of the plane iron should protrude from the plane of the sole by the thickness of the chip being removed. First, the blade of the piece of iron is installed, then its angles are adjusted. With proper installation, the chips should be the same width in all areas. They fix the piece of iron like this: the block is placed with the sole on a flat surface of the board and, pressing it with the left hand to the board, with the right hand, insert the piece of iron into place. The piece of iron is set so that it protrudes from the plane of the sole to the required length: for a planer with a single knife - up to 1 mm, for a sherhebel - up to 3 mm, etc. For metal planers, the knife is adjusted using a screw. After each adjustment it is necessary to make a trial planing.

For double knives, the second knife, which is also called a chipbreaker, is installed with a minimum gap in relation to the first knife. When setting up planers, you often have to sharpen the blade. Its cutting edge is sharpened at a right angle to the side edge.

Manual planing. Before proceeding with the planing work, it is necessary to select wood, that is, to establish its suitability for the manufacture of any part. At the same time, convexities and concavities are revealed that must be removed by planing, as well as wood defects and determine whether they are acceptable for this part. For planing, it is necessary to fix the workpiece so that the direction of the wood fibers coincides with the planing direction. The deflection of the workpiece indicates that the fastening should be slightly loosened. At the beginning of planing, the tool is pressed with the left hand, towards the middle the efforts of both hands are leveled, and at the end they are pressed right hand so as not to overwhelm the end of the part. They cut calmly, slowly, but confidently, in full swing, with a uniform feed of the tool in all areas. The body of the worker should be slightly tilted forward, left leg pushed forward, and the right one is at an angle of 70 ° with respect to the left. The quality of planing is controlled by a ruler, well-adjusted bars and a square. If there are no gaps between the ruler and the planed workpiece, the tool is finished working.

When planing, the cleanliness of the surface depends on the distance from the place of the chip cleavage to the knife blade (the closer the cleave is from the taphole slot, the cleaner the planing), as well as on the steepness of the chip crease when entering the taphole slot (a steep crease is cut faster by the knife, resulting in a shorter length). chip). In a planer with a double knife, the second knife performs the function of breaking the chips, and the closer it is to the blade of the first knife, the cleaner the surface is. Typically, the width of the chipbreaker (second knife) is no larger than the width of the first knife. You can learn about the state of the gap and the cutting part of the knives by the type of chips coming out of the tap hole. If the chipbreaker is blunt, the chips come out straight and the planing surface is clean; if it is very sharp, the chips come out in rings, so the sharpened edge of the chipbreaker is slightly dulled.

In carpentry, drilling is used to make holes for round spikes, screws and other metal elements when connecting parts, under corks when removing knots, under grooves when processing wood with a chisel and a chisel. The principle of operation of any drill is that, going deep into the wood, with its cutting edges selects the material, forming a hole.

Types of drills and their preparation for work

Drills are feather, center, spiral, screw (Fig. 1). The drill distinguishes the shank, the rod itself, the cutting part and the elements for chip removal.

Spade drills spoon-type perks have the form of an elongated trough with sharp edges (see Fig. 1, a). They serve for drilling holes for pins with a diameter of 3 ... 16 mm (with a drill length of up to 170 mm). During the drilling process, the perk is periodically removed from the wood to remove chips. The disadvantage of the feather drill is the lack of a guide center. Used to drill larger holes spade drills other structures (see Fig. 1, b).

Center drills(see Fig. 1, c) through, but shallow holes are drilled across the wood fibers, since the exit of chips in them is difficult. Such drills work only in one direction and when pressed from above. Their diameter is up to 50, length - up to 150 mm.

Twist drills(see Fig. 1, d) are more perfect in their design. They provide for the removal of chips, as a result of which the hole does not clog when drilling with chips and has clean, even walls. Like centers, these drills have a center and a cutter or a conical sharpening of the cutting part. The diameter of drills with conical sharpening is 2…6 mm (short series) and 5…10 mm (long series), and with a center and cutter - 4…32 mm. Drills with conical sharpening are used for drilling along the fibers, with a center and cutter - across. Twist drills can be equipped with tungsten carbide blades for particularly hard woods.

Screw drills(see Fig. 1, e) are used mainly for drilling deep holes across the grain of the wood. After passing through this drill, the walls of the hole are clean. Drill diameter t - up to 50, length - up to 1100 mm.

Used for drilling large holes cork drills, and to expand the holes for the heads of screws or nuts - countersinks (Fig. 2). When drilling wood, metal drills are also used, reducing their sharpening angle.

The drill must be properly sharpened, otherwise it will tear, not cut the wood, and the hole will become clogged with chips. When sharpening, it is necessary to maintain the straightness of the cutting edges. Since the cutting head has a limited supply of metal, the drill should be sharpened carefully and economically. It is sharpened on an abrasive stone (Fig. 4, a) or manually with a thin square file, and finished with a special whetstone. Typically, the sharpening angle of the drill is 12°.

Center drills begin to sharpen from the inside of the cutting edge, the rest - from the outside. The correctness of sharpening is checked with a template (Fig. 4, b). The ends of the lateral incisors must protrude at least 3 mm above the cutting edges of the horizontal incisors. This allows the ridges to start cutting before the horizontal cutters start to cut the chips.

The cleanliness of the hole processing and the accuracy of drilling depend primarily on how the drill is sharpened. The transverse cutting edge must pass through the axis of the drill. When it is displaced from the axis, the drill will go to the side, as a result of which there will be uneven wear of the cutting edges and the beat of the drill, and, consequently, an increase in the diameter of the hole.

Rice. 1. Drills for working with wood: a, b - feather; in - center; g - spiral; d - screw.	Rice. 2. Cork drill (a) and countersink (b).
Rice. 3. Device for drilling holes of large diameter: 1 - drill chuck; 2 - metal rods; 3 - wooden circle; 4 - saw blade; 5 - centering drill.	Rice. 4. Sharpening the drill on the sharpener (a) and checking the correctness of sharpening according to the template (b).
Rice. 5. Manual screw drill (a) and brace (b): 1 - pressure head; 2 - handle; 3 - steel rod with thread; 4 - clamping chuck; 5 - ring, switch; 6 - ratchet mechanism.	Rice. 6. Additional tool for drilling: a - drill; b - gimlet; c - spoon drill.

For drilling in solid a large number identical holes, it is necessary to have several drills of the same diameter in stock. Periodic change of drills will increase their service life.

Manual drilling of wood. Wood is drilled with a drill and a brace. To fix drills in them, clamping chucks of various designs are used.

Hand screw drill(Fig. 5, a) serves mainly for drilling holes with a diameter of up to 5 mm. On its core there is a screw thread for moving the handle. The force from the hand squeezing the handle is transferred to the rod, and the ok begins to rotate. The second hand acts on the pressure head. From the combination of these two efforts, the drill is introduced into the wood, i.e., the cutting process.

At brace(Fig. 5, b) the cutting process comes from the force that the worker's hand creates when rotating the crankshaft rod with a handle in the middle. At the bottom of the rod there is a chuck with a ratchet, which makes it possible to set the rotation to the right and left. Drills with a diameter of up to 10 mm can be attached to the brace.

To drill holes, their centers must be marked. When marking, the hardness of the wood, the degree of its splitting, the location of cracks and knots, the direction and depth of drilling, the presence of nails, metal staples, etc. are taken into account. Usually, the centers of the holes are pierced with a scriber or a trihedral awl to the depth of the drill diameter. When drilling holes of large diameters, their centers are pre-drilled with thin drills so that the drill does not go to the side. The centers of deep through holes are drilled on both sides; at the same time, the drilling process itself is also performed (i.e., from both sides). The diameter of the drill for drilling under the screws must be 0.5 mm smaller than the diameter of the middle part of the screw. In brittle wood and at the ends for the screw heads, it is recommended to make a lowering (counterboring) so that during further operations (priming, puttying and painting) the screw heads are flush with the surface of the part.

When making through holes, it is necessary to put an obstacle at the exit of the drill (for this you can use a piece of wood), otherwise chips or cracks will inevitably form in the workpiece. When drilling, the tool must not be turned towards you. It is not recommended to work with unsharpened drills and drills with chipped cutting parts and cracks. You should pay attention to the centering of the drill in the chuck, since the correct drilling depends on this. From a strong beat, the drill will inevitably go to the side. Correct sharpening drills will avoid the application of excessive force and getting a torn surface. An increase in the applied force leads to damage to the part and breakage of the drill, and also creates a traumatic situation.

For drilling deep holes in solid wood borer(Fig. 6, a), and shallow holes in hardwood for screws - gimlet(Fig. 6b). A drill is a metal rod with an eye for a handle at the top and a helical surface with a guide center at the bottom. The gimlet has difficulty removing chips from the hole, so it is periodically removed from the hole and cleaned of chips. A drill and a gimlet do not give the cleanliness of processing that can be obtained when drilling with drills. Carpentry craftsmen have spoon gimlets (Fig. 6, c). In fact, these are the same perks, only with a sharp tip and a conical screw.

The method of working with a drill is as follows: first, it is installed in the intended place with a point, and then, with a certain effort, it is pressed against the tree. When the tip goes deep into the tree, then further pressure is no longer needed, it is only necessary to turn the tool by the handles. Unfortunately, the drill does not cut, but tears the wood, and sometimes cracks and splits appear in the workpiece, especially near the end. Drills are used for non-responsible carpentry work and in carpentry.

Splicing and rallying wood

Splice widely used for producing long beams, in the construction of furniture frames, connecting skirting boards, making drawers for table tops, etc. The most widely used gear connection (as the most durable), forming large area gluing. One and a half parts are spliced ​​at baseboards when tying panels, i.e., for parts that do not experience significant load. Cutting is carried out in a marking box (miter box) at an angle of 45 °. A sharper angle is used for increased load, especially for bending.

Parts that are under tensile stress are spliced ​​with an open dovetail spike. Details with a support at the bottom, which experience forces that tend to move them in different directions, are spliced ​​onto a plug-in round spike. When replacing parts in a product, they are refinished, which is performed by splicing or building up, depending on the shape of the part in section (Fig. 2).

Rice. one. : a - end; b - on the "mustache"; c - serrated.

Rice. 2. : a - in half a tree; b - oblique cut; in - in the direct laid on lock; d - in an oblique laid on lock, d - in a straight tension lock; e - in an oblique tension lock; g - back to back; h - back to back with a hidden spike; and - end-to-end with the end comb; to - end-to-end with a plug-in spike (pin); l - in half a tree with bolting; m - half a tree with fastening with strip iron; n - in half a tree with fastening with clamps; o - with an oblique cut and fastening with clamps; p - back to back with overlays.

Rice. 3. Joining wood by the method of rallying along the width of the edge: a - on a smooth fugue; b - in a quarter; in - in rectangular groove and a comb along the edge; g - in a trapezoidal groove and a ridge along the edge; d - in the groove and rail.

Rallying used in cases where it is necessary to connect carpentry material along the width of the edge into shields or blocks (Fig. 3). The most common rallying method is riveting into a smooth reveal. In this case, the edges of the joined sections are tightly jointed along the entire length and compressed with glue. In addition to this simple method, puffer jointing and plug-in round or flat studs are also used. The rallying into a quarter is performed dry, without glue, and the sponge of the quarter facing the non-front side should be 0.5 mm narrower than the sponge facing the front side. Rallying into a groove and a crest is performed with and without glue. Rallying into a groove on a rail with precise jointing of the joined sections and high-quality gluing is the most durable and economical, since the material for the comb is taken from wood waste.

Joinery wood bending technology

In the manufacture of furniture, you can not do without curvilinear parts. You can get them in two ways - sawing and bending. Technologically, it would seem that it is easier to cut a curved part than to steam, bend and then withstand it for a certain time until it is fully ready. But sawing has a number of negative consequences.

Firstly, there is a high probability of cutting the fibers when working with a circular saw (it is used in this technology). The result of cutting the fibers will be the loss of strength of the part, and, as a result, of the entire product as a whole. Secondly, sawing technology involves a greater consumption of material than bending technology. This is obvious and no comment is required. Thirdly, all curved surfaces of sawn parts have end and half-end cut surfaces. This significantly affects the conditions for their further processing and finishing.

Bending avoids all these disadvantages. Of course, bending involves the presence of special equipment and fixtures, and this is not always possible. However, bending is possible in the home workshop. So, what is the technology of the bending process?

The technological process of manufacturing bent parts includes hydrothermal treatment, bending of blanks and their drying after bending.

Hydrothermal treatment improves the plastic properties of wood. Plasticity is understood as the property of a material to change its shape without destruction under the action of external forces and retain it after the action of forces is eliminated. Wood acquires the best plastic properties at a moisture content of 25 - 30% and a temperature in the center of the workpiece by the time of bending of about 100 ° C.

Hydrothermal treatment of wood is carried out by steaming in boilers with saturated steam. low pressure 0.02 - 0.05 MPa at a temperature of 102 - 105°C.

Since the duration of steaming is determined by the time it takes to reach the set temperature in the center of the steamed workpiece, the steaming time increases with increasing thickness of the workpiece. For example, for steaming a workpiece (with an initial humidity of 30% and an initial temperature of 25°C) with a thickness of 25 mm to reach a temperature in the center of the workpiece of 100°C, 1 hour is required, and a thickness of 35 mm - 1 hour and 50 minutes.

When bending, the workpiece is placed on a tire with stops (Fig. 1), then in a mechanical or hydraulic press, the workpiece together with the tire is bent to a given contour; in presses, as a rule, several workpieces are bent simultaneously. At the end of bending, the ends of the tires are pulled together with a coupler. The bent blanks are sent for drying along with the tires.

The workpieces are dried for 6-8 hours. During drying, the shape of the workpieces stabilizes. After drying, the blanks are freed from templates and tires and kept for at least 24 hours. After holding, the deviation of the dimensions of the bent blanks from the original ones is usually ± 3 mm. Next, the blanks are processed.

For bent blanks, peeled veneer, urea-formaldehyde resins KF-BZh, KF-Zh, KF-MG, M-70, particle boards P-1 and P-2 are used. The thickness of the workpiece can be from 4 to 30 mm. Blanks can have a wide variety of profiles: angular, arc-shaped, spherical, U-shaped, trapezoidal and trough-shaped (see Fig. 2). Such blanks are obtained by simultaneous bending and gluing together veneer sheets lubricated with glue, which are formed into packages (Fig. 3). This technology makes it possible to obtain products of a wide variety of architectural forms. In addition, the production of bent glued parts from veneer is economically feasible due to the low consumption of timber and relatively low labor costs.

Layers of plots are smeared with glue, laid in a template and pressed in (Fig. 4). After exposure under the press until the glue has completely set, the knot retains the shape given to it. Bent glued knots are made from veneer, from hardwood and coniferous plates, from plywood. In curved glued veneer elements, the direction of the fibers in the veneer layers can be either mutually perpendicular or the same. The bend in the veneer, in which the grain of the wood remains straight, is called a bend across the grain, and in which the grain is bent, it is called a bend along the grain.

When constructing bent glued veneer assemblies that carry significant loads during operation (legs of chairs, cabinet products), the most rational designs are those with a bend along the fibers in all layers. The rigidity of such knots is much higher than knots with mutually perpendicular direction of wood fibers. With a mutually perpendicular direction of the veneer fibers in the layers, bent glued knots up to 10 mm thick are designed that do not carry heavy loads during operation (walls of boxes, etc.). In this case, they are less susceptible to form change. The outer layer of such knots should have a fractional direction of the fibers (bending along the fibers), since when bent across the fibers, small fractional cracks appear at the bending points, which exclude a good finish of the product.

Permissible (curvature radii of curved veneer elements depend on the following design parameters: veneer thickness, number of veneer layers in a package, package design, billet bending angle, mold design.

In the manufacture of bent profile units with longitudinal cuts, it is necessary to take into account the dependence of the thickness of the bent elements on the type of wood and the thickness of the bent part.

In the tables, the elements remaining after the cuts are called extreme, the rest - intermediate. The minimum distance between cuts that can be obtained is about 1.5 mm.

With an increase in the bending radius of the plate, the distance between the cuts decreases (Fig. 5). The width of the cut depends on the bending radius of the board and the number of cuts. To obtain rounded nodes, in the slab, after veneering and grinding, a groove is selected in the place where the bend will be. The groove can be rectangular or dovetail. The thickness of the remaining plywood bridge (the bottom of the groove) should be equal to the thickness of the facing plywood with an allowance of 1-1.5 mm. A rounded bar is inserted into the rectangular groove with glue, and a strip of veneer is inserted into the dovetail groove. Then the plate is bent and kept in the template until the glue sets. To give the corner greater strength, a wooden square can be placed in it from the inside.

Spike connections

The simplest carpentry connection can be represented as a connection of a spike into a socket or into an eye (Fig. 1). A spike is a protrusion at the end of the bar (Fig. 2), a nest is a hole into which the spike enters. Spike joints are divided into corner end, corner middle and corner box.

In the practice of amateur carpenters, corner end connections are very common. To calculate the elements of such compounds are fig. 3 and table.

Suppose it is necessary to calculate the connection on the "mustache" with a plug-in through flat spike (UK-11). The thickness of the joined bar is known (let s0 = 25 mm). Then, taking this size as a basis, we determine the size s1. According to the table, s1 = 0.4 mm, s0 = 10 mm.

Let's take the UK-8 connection. Let the dowel diameter be 6 mm, then l (we choose the average value - 4d) is 24 mm, and l1 = 27 mm. Pin connections are made symmetrically to each other and with respect to the plane of the part, therefore, according to Fig. 3 h, the distance from the center of the hole for the lower pin to the center of the hole for the upper pin will be at least 2d, or 12 mm; the same distance from the center of the dowel hole to the end of the part to be joined.

On fig. 4 shown schemes of angular middle (tee) joints , for which the following basic dimensions of studs and other elements must be observed in the calculation: in US-1 and US-2 joints, the use of a double stud is allowed, while s1 = 0.2s0, l1 = (0.3 ... 0.8) B, l2 = (0.2…0.3) В1; in US-3 compound s1 = 0.4s0, s2 = 0.5 (s0 - s1); in US-4 compound s1 = s3 = 0.2s0, s2 = 0.5 X [s0 - (2s1 + s3)]; in US-5 connection s1 = (0.4…0.5)s0, l = (0.3…0.8)s0, s2 = 0.5 (s0-s1), b ≥ 2 mm; in connection US-6 l = (0.3… 0.5)s0, b ≥ 1 mm; in connection US-7 d = 0.4 at l1 > l by 2…3 mm; in connection US-8 l = (0.3…0.5) B1, s1 = 0.85s0.

Dimensions of spikes and other elements of angled end connections

Connections	s 1	s2	s3	l	l 1	h	b	d
UK-1	0.4s0	0.5 (s0 - s1)	-	-	-	-	-	-
UK-2	0.2s0	0,5	0.2s0	-	-	-	-	-
UK-3	0.1s0	0,5	0.14s0	-	-	-	-	-
UK-4	0.4s0	0.5 (s0 - s1)	-	(0.5…0.8)V	(0.6…0.3)l	0.7B 1	≥ 2 mm	-
UK-5	0.4s0	0.5 (s0 - s1)	-	0.5V	-	0.6B 1	-	-
UK-6	0.4s0	0.5 (s0 - s1)	-	(0.5…0.8)B	-	0.7B 1	≥ 2 mm	-
UK-7	-	0.5 (s0 - s1)	-	-	-	0.6B 1	-	-
UK-8	-	-	-	(2.5…6)d	l 1 > l by 2…3 mm	-	-	-
UK-9	-	-	-	(2.5…6)d	l 1 > l by 2…3 mm	-	-	-
UK-10	0.4s0	-	-	(1…1.2)B	-	-	0.75B	-
UK-11	0.4s0	-	-	-	-	-	-	-

Note. The dimensions s0, B and B1 are known in each particular case.

Rice. one. : a - in the nest; b - in the eye; 1 - spike; 2 - socket, eyelet.

In the corner box joints, the spikes are repeated many times. Basically, three types of such connections are used: on a straight open spike (see Fig. 3, a); open “dovetail” on the spike (see Fig. 2, e); on an open round plug-in spike - dowel (see Fig. 3, h).

Often use the method of connecting to a dowel (nagel). A dowel is a cylindrical stick made of birch, oak, etc. It is evenly machined and hammered into pre-drilled holes - channels pre-lubricated with glue. Holes for dowels are made in both parts at once. The dowel should enter the hole tightly, with the help of mallet blows. The drill for preparing the holes must match the size of the dowel. To reduce the diameter of the dowel, grinding with sandpaper or a bastard file is used (risks are made not across, but along the dowel).

When choosing a connection, it is necessary to consider first of all the nature and magnitude of the load, as well as how the connection will resist the load. For example, when connecting a cabinet shelf close to the wall, the entire load will fall on the screws or dowels. The force with which the product (shelf) presses on them causes them to resist shearing and breaking. Therefore, the load here is made small. In this case, it is more expedient to install a wooden rail under the shelf, screwing it tightly to the cabinet wall. The load will increase, but the resistance to it will also increase due to not only screws, but also friction between the rail and the cabinet wall. A significantly greater load can be tolerated if the shelf is cut at least to a small depth into the wall array; in this case, the furniture wall itself will take the load.

Rice. 3. : a - open through single spike - UK-1; b - open end-to-end double spike - UK-2; c - on the spike open through triple - UK-3; g - on a thorn with a half-dark blindness - UK-4; d - on a spike with a half-dark end-to-end UK-5; e - on a spike with blind darkness - UK-6; g - on a spike with a dark through - UK-7; h - on spikes round plug-in, non-through and through - UK-8; and - on the "mustache" with a plug-in non-through round spike - UK-9; to - on the "mustache" with a plug-in non-through flat spike - UK-10; l - on the "mustache" with a plug-in through flat spike - UK-11.

Rice. 4. : a - single non-through spike - US-1; b - sewed single blind into the groove - US-2; c - on a single through spike - US-3; g - on a double through spike - US-4; d - into the groove and non-through crest - US-5; c - into the non-through groove - US-6; g - on spikes round plug-in non-through - US-7; h - on the spike "dovetail" blind - US-8.

From a comparison of the resistances of two connections (half-wood with a screw and a dovetail), it can be seen that the connection in the dovetail can withstand a load three times greater than the connection in half-wood with a screw. Based on this and a number of other examples, we can draw the following conclusions about the appropriateness of using certain joints: joinery knitting should be selected in accordance with the magnitude and direction of the load on the joint; the load must be taken directly by the design of the product ( additional fasteners there may be a screw, a metal square, a dowel, etc.); knitting with gaps is not allowed.

Gluing should be done only with prepared surfaces: the rougher, for example, the surface of the dowel, the more reliably it will stick to the array.

A myriad of connections can be used to connect wooden parts. The names and classifications of joinery-carpentry joints tend to vary considerably by country, region, and even school of woodworking. The craftsmanship lies in the fact that the precision of execution provides a correctly functioning connection that is able to withstand the loads intended for it.

Initial information

Connection categories

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

• box;
• frame (frame);
• for splicing/splicing.

Drawer connections are used, for example, in the manufacture of drawers and cabinets, frame connections are used in window frames and doors, and rallying / splicing is used to obtain parts with an increased width / length.

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

Material preparation

Even planed lumber may need some preparation.

• Trim the material with a margin in width and thickness for further planing. Don't cut to length yet.
• Choose the best quality layer - the front side. Plane it along the entire length. Check with a straightedge.
  After final alignment make a mark on the front side with a pencil.
• Plane the front - clean - edge. Check with a straightedge, as well as a square against the front side. Smooth out warp by planing. Mark a clean edge.
• Use a thickness gauge to mark the required thickness along all edges of the part contour. Plan up to this risk. Check with a straightedge.
• Repeat the operation for the width.
• Now mark up the length and actual connections. Mark from the front side and a clean edge.

Lumber marking

Be careful when marking lumber. Make sufficient allowances for kerf width, planing thickness and joining.

All readings are taken from the front side and the clean edge, on which put the appropriate marks. In frame and cabinet designs, these marks should face inward to improve manufacturing accuracy. For ease of sorting and assembly, number the parts as they are manufactured on the front side so that, for example, it indicates that side 1 is connected to end 1.

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

Butt joints

These are the simplest of joinery and carpentry joints. They can be included in all three categories of compounds.

Assembly

The butt joint can be reinforced with nails hammered at an angle. Drive the nails in randomly.

Trim the ends of the two pieces evenly and join them. Secure with nails or screws. Before this, glue can be applied to the parts to enhance fixation. Butt joints in frame structures can be reinforced with a steel plate or a corrugated key on the outside, or with a wooden block fixed on the inside.

Nail / dowel connections

Wooden dowels - today they are increasingly called dowels - can be used to strengthen the connection. These plug-in round spikes increase shear (shear) strength and, with adhesive, hold the assembly in place more securely. Dowel connections can be used as frame connections (furniture), drawer connections (cabinets) or for splicing (panels).

Assembling the dowel joint

1. Carefully cut out all the components to exactly the right dimensions. Mark the position of the crossbar on the face and clean edge of the upright.

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

Mark the center lines for the pins on the end of the crossbar and transfer them to the rack using the square.

3. Lay the upright and bar face up. On the square, transfer the center lines to the rack. Number and label all connections if there are more than one pair of uprights and crossbars.

4. Transfer this marking to the clean edge of the post and the ends of the crossbar.

5. From the front side with a thickness gauge, draw a risk in the center of the material, crossing the marking lines. This will mark the centers of the holes for the dowels.

With a thickness gauge, draw a center line, crossing the marking lines, which will show the centers of the dowel holes.

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

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

Nagels

The pin should have a longitudinal groove (now standard pins are made with longitudinal ribs), through which excess glue will be removed when assembling the joint. If the dowel does not have a groove, then cut 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.

Use of pins for marking dowels

Mark and drill the crossbars. Insert special dowel pins into the pin holes. Align the crossbar with the markings of the rack and squeeze the parts together. The tips of the teats will make marks on the rack. Drill holes through them. Alternatively, you can make a template out of a wooden block, drill holes in it, fix the template on the part and drill holes for the dowels through the holes in it.

Using a jig for a dowel connection

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

conductor for nail joints

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

2. Align the alignment marks on the side of the jig and secure the slide bearing of the guide bush.

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

4. Install the drilling depth gauge on the drill at the desired location.

Rallying

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 the wide sides together, line up the ends exactly, and clamp the pair in a vise. On a clean edge, draw perpendicular lines indicating the center lines of each dowel. In the middle of the edge of each board, with a thickness gauge, make risks across each previously marked center line. The intersection points will be the centers of the dowel holes.

The pin connection is neat and strong.

Flange / mortise connections

A notch, tie-in or groove connection is called a corner or middle 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. It is used in frame (house frames) or box (cabinets) connections.

Types of mortise / mortise connections

The main types of butt joints are the dark/semi-dark T-joint (often this term is replaced by the term "flush/semi-flush"), which looks like a butt joint, but is stronger, a quarter corner (corner joint) and a dark/semi-dark corner joint. A corner cut into a rebate and a corner cut 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.

Making a cut

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

2. Use a thickness gauge to 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 part of the material.

3. C-clamp the workpiece securely. Saw through the shoulders on the waste side of the marking lines to the desired 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 return side, making intermediate cuts with a wide groove.

4. Working with a chisel on both sides, remove excess material and check the flatness of the bottom. To level the bottom, you can use a primer.

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

5. Check the fit, if the piece is too tight it may need to be trimmed. Check for perpendicularity.

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

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

The notch connection is strong enough

Tongue and groove connections

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 of window openings.

Making a connection

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

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

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

4. With a hacksaw with a butt, saw through the shoulders to the risks of the thicknesser. Remove waste with a chisel and check for evenness.

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

Adviсe:

• Tongue and groove type joints can be easily made with a router and an appropriate guide, either for the groove only or for both the groove and rebate. See p. 35.
• If the comb is too tight in the groove, trim the front (smooth) side of the comb or sand with sandpaper.

6. From the front side with a thickness gauge, make markings on the edges towards the end and on the end itself. Saw along the lines of the thickness gauge with a hacksaw with a butt. Do not cut too deep as this will weaken the connection.

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

Half tree connections

Half-timber connections refer to frame connections, which are used to connect parts in layers or along an edge. The connection is made by taking the same amount of material from each part so that they are joined flush with each other.

Types of joins in half-tree

There are six main types of connections in the half-tree: transverse, angular, flush, angular mustache, dovetail and splicing.

Making a half-tree gusset

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 at 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 and the bottom side of the other part.

3. Clamp the part in a vise at an angle of 45° (face vertically). Carefully cut along the grain close to the thicknesser line on the back side until the saw is diagonal. Flip the piece over and continue sawing gently, gradually raising the saw handle until the saw lines up with the shoulder line on both edges.

4. Remove the part from the vise and place it on the face. Press it firmly against the hutch and clamp it with a clamp.

5. Saw through the shoulder to the previous cut and remove the waste. Align all irregularities in the sample with a chisel. Check the accuracy of the cut.

6. Repeat the process on the second piece.

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

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

Corner joints on the mustache

Corner joints on the mustache are made using the bevel of the ends and hide the end grain, and also aesthetically correspond more to the angular rotation of the decorative overlay.

Types of corner connections on the mustache

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

Making a corner connection

1. Mark the length of the parts, keeping in mind that it should be measured on the long side, as the bevel will reduce the length inside the corner.

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

3. With a combination square, transfer the markup to all sides of the part.

4. When hand cutting, use a miter box and a backed hacksaw or hand miter saw. Press the part firmly against the back of the miter box - if it moves, the bevel will turn out uneven and the joint will not fit well. If you are sawing freehand, be careful not to deviate from the marking lines on all sides of the part. A miter saw, if you have one, will make a very neat bevel.

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

6. The connection should be knocked down with nails through both parts. To do this, first lay the parts on the face and drive nails into the outer side of the bevel so that their tips slightly show out of the bevels.

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

7. Apply glue and squeeze the joint tightly so that one part protrudes slightly - overlaps the other. First, drive nails into the protruding part. Under hammer blows when driving nails, the part will move slightly. Surfaces must be level. Nail the other side of the connection and sink the nail heads. Check squareness.

Drive the nails into the protruding piece first, and the impact of the hammer will move the joint into position.

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

9. To reinforce the corner joint on the mustache, you can glue a wooden block inside the corner if it is not visible. If appearance is important, then the connection can be made on a plug-in spike or secured with veneer dowels. Pins or lamellas (standard flat studs) can be used inside the flat joints.

Splicing on a mustache and connection with cutting

Splicing on a mustache connects the ends of parts located on the same straight line, and a connection with a cut is used when it is necessary to connect two profile parts at an angle to each other.

Mustache splicing

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

Cutting connection

Connection with cutting (cutting, fitting) is used when it is necessary to connect two parts with a profile in the corner, for example, two skirting boards or cornices. If the part moves during its fastening, then the gap will be less noticeable than with a corner joint.

1. Fix the first skirting board in place. Move the second plinth close to it, located along the wall.

Fasten the first skirting board in place and press the second skirting board against it, aligning it with the wall.

2. Swipe along the profiled surface of the fixed plinth with a small wooden block with a pencil pressed against it. The pencil will leave a marking line on the plinth to be marked.

With a bar with a pencil pressed against it, attached with a tip to the second plinth, draw along the relief of the first plinth, and the pencil will mark the line of the cut.

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

Complex profiles

Lay 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 desired shape. Cut along this line with a jigsaw.

Eyelet connections

Eyelet connections are used when it is required to join intersecting parts located "on the edge", either in the corner or in the middle (for example, the corner of the window frame or where the leg of the table connects to the crossbar).

Eyelet connection types

The most common types of eye connections are angle and tee (T-shaped). For strength, the connection must be glued, but you can strengthen it with a dowel.

Making an eyelet connection

1. Mark out in the same way 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 choose the middle. This groove is called an eyelet. On the second part, both side parts of the material are removed, and the remaining middle part is called a spike.

2. Saw along the fibers to the line of the shoulders along the marking lines on the side of the waste. Cut out the shoulders with a hacksaw with a butt, and you get a spike.

3. Working on both sides, select the material from the eyelet with a chisel/grooving chisel or jigsaw.

4. Check the fit and fine-tune with a chisel if necessary. Apply adhesive to the joint surfaces. Check squareness. Use a C-clamp to clamp the joint while the adhesive cures.

Spike-to-socket connection

Spike-to-socket connections, or just spike connections, are used when two parts are connected at an angle or at an intersection. It is probably the strongest of all frame joints in carpentry and is used in the manufacture of doors, window frames and furniture.

Types of spike-to-socket connections

The two main types of stud joints are the usual stud-in-socket connection and the stepped stud-in-socket connection (semi-dark). The spike and socket are approximately two-thirds of the width of the material. The expansion of the nest is made on one side of the groove (semi-darkness), and a spike step is inserted into it from its corresponding side. Semi-darkness helps to prevent the thorn from turning out of the nest.

Standard spike-to-socket connection

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

2. Pick up a chisel as close as possible in size to a third of the thickness of the material. Set the thickness gauge to the size of the chisel and mark the nest in the middle of the rack between the previously marked marking lines. Work from the front. If desired, you can set the thickness solution to a third of the thickness of the material and work with it on both sides.

3. In the same way, mark the spike on the butt and both sides to mark the shoulders on the crossbar.

4. Clamp a piece of wood secondary support in a vise high enough to attach the edge-on stand to it. Fasten the post to the support by placing the clamp next to the marking of the nest.

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

6. Make a few intermediate cuts, holding the chisel at a slight angle and bevel down. Select the waste by using the chisel as a lever. Going deeper by 5 mm, make more cuts and select a waste. Continue until about half the thickness. Flip the part over and work the same way on the other side.

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

8. Cut the spike along the fibers, leading a hacksaw with a butt along the marking line from the side of the waste, and cut out the shoulders.

9. Check fit and adjust if necessary. The shoulders of the cleat must fit snugly against the post, and the joint must be perpendicular and free from play.

10. Wedges can be inserted on both sides of the spike to secure. A gap for this is made in the nest. Working with a chisel from the outside of the nest, widen about two thirds of the depth with a 1:8 slope. Wedges are made with the same slope.

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

Other spike connections

Stud joints for window frames and doors are somewhat different from half-dark stud joints, although the technique is the same. Inside there is a fold and / or an overlay for glass or a panel (panel). When making a connection with a spike into a socket on a part with a seam, make the plane of the spike in line with the edge of the seam. One of the shoulders of the crossbar is made longer (to the depth of the fold), and the second is shorter so as not to block the fold.

Studded joints for parts with overlays have a cut-off shoulder to match the profile of the overlay. Alternatively, you can remove the trim from the edge of the socket and make a bevel or cut to match the counterpart.
Other types of spike-to-socket connections:

• Side spike - in the manufacture of doors.
• A hidden beveled spike in semi-darkness (with a beveled step) - to hide the spike.
• Spike in the dark (steps of the stud on its two sides) - for relatively wide details, such as the lower trim (bar) of the door.

All these connections can be through, or they can be deaf, when the end of the spike is not visible from the back of the rack. They can be reinforced with wedges or dowels.

Rallying

Wide, high-quality wood is becoming increasingly difficult to find and very expensive. In addition, such wide boards are subject to very large shrinkage deformations, which makes it difficult to work with them. To connect narrow boards along the edge into wide panels for worktops or workbench covers, rallying is used.

Training

Before starting the actual rallying, you must do the following:

• If possible, select radial sawn boards. They are less susceptible to shrinkage than tangential sawn timber. If boards of tangential sawing are used, then lay their sound side alternately in one and the other side.
• Try not to bundle materials with different sawing methods into one panel.
• Never join boards of different types of wood unless they are properly dried. They will shrink and crack.
• If possible, arrange the boards with the fibers in one direction.
• Be sure to cut the material to size before stapling.
• Use only good quality glue.
• If the wood will be polished, adjust the texture or color.

Rallying for a smooth fugue

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

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

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

4. When planing short parts, clamp two in a vise front sides together and plan both edges at the same time. It is not necessary to maintain the squareness of the edges, since when docking they will mutually compensate for their possible inclination.

5. Prepare as for a butt joint and apply adhesive. Squeeze with lapping to connect the two surfaces, squeezing out excess glue and helping the surfaces to “stick” to each other.

Other payment methods

Other fusion joints with different amplifications are prepared in the same way. These include:

• with pins (dowels);
• in a groove and a comb;
• in a quarter.

Bonding and clamping

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

Adhesives

The adhesive reinforces the connection, holding the parts together so that they cannot be easily pulled apart. Be sure to wear protective gloves when handling adhesives and follow the safety instructions on the packaging. Clean the product of excess glue before it sets, as it can dull the planer knife and clog the abrasive of the skin.

PVA (polyvinyl acetate)

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

contact adhesive

Contact adhesive sticks together immediately after application and connection of parts. Apply it to both surfaces and when the glue is dry to the touch, join them. It is used for laminate (laminate) or veneer to chipboard. Fixing is not required. Cleaned with solvent. Contact adhesive is flammable. Work with it in a well ventilated area to reduce the concentration of fumes. Not recommended for outdoor use, as it is not moisture and heat resistant.

Epoxy adhesive

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

hot glue

Hot melt adhesive bonds almost everything, including many plastics. Usually sold in the form of glue sticks that are inserted into a special electric glue gun for gluing. Apply glue, join surfaces and squeeze for 30 seconds. Fixing is not required. Cleaned with solvents.

Clips for fixation

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 piece of wood waste between the clamp and the product to avoid denting from applied pressure.

Gluing and fixing technique

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

Frame assembly

Spread the adhesive evenly with a brush on all surfaces to be glued and quickly assemble the product. Remove excess adhesive and secure assembly with clips. Compress the connections with even pressure. The clamps must be perpendicular and parallel to the surfaces of the product.

Position the clamps as close as possible to the connection. 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 slight but sharp blow to one end of the rack can even out the shape. Adjust clamps if necessary.

If the frame does not lie flat on a flat surface, use a mallet to tap the protruding sections through a piece of wood as a spacer. If that doesn't work, you may need to loosen the clamps or clamp the wood block across the frame.

Connections of wooden elements have the task of connecting mating Construction Materials, such as edged beams, so that they do not move relative to each other. According to the position and direction of the connected wooden elements, longitudinal joints and corner joints, as well as joints on branches and crosses, are distinguished. Spatial connectors from steel sheet and pre-drilled steel plate escutcheons often replace carpentry 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, such as compressed rods. Compressed rods connected at an acute angle can be connected at notches. Other connections of wooden structures are arranged at the expense of joints of wooden elements using connecting means.

According to the type of connecting means, such connections are called nail or bolt, dowel or dowel connections. In the construction of wood, glued building structures are also used. Since they have particular advantages, the use of glued timber structures is of increasing importance.

Longitudinal connections

There are longitudinal connections on the supports and longitudinal connections in the span. Above the supports, perpendicular trunnions are used, a joint “in the paw” and a partially trunnion joint “in the paw” (Fig. 1). To reinforce these joints, building brackets made of flat or round steel can be driven in from above or from the side. Often, wooden elements are joined head-on and fixed only with building brackets. If, however, large tensile forces act at the joint, for example, at the girders on the roof rafters, then both elements are joined head-on on the support and connected by side plates made of boards or perforated strips of steel protected from corrosion.

Rice. 1. Longitudinal connections

Runs can also be made in the form cantilever-suspended(Gerber runs) or hinged girders. They have a joint located in a place determined by the 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 runs are connected with a straight or oblique overlay. The incoming purlin is held in place by a screw bolt, also called a pivot bolt. The swivel bolt with washers must bear the load from the suspended purlin.

Rice. 2. Longitudinal joints of Gerber girders

Gerber purlins with a seam lying on top are impractical, since there is a danger that the purlins at the edge of the seam will come off. With a suspended joint, having screwed up, there is no danger of separation.

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

Corner connections

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

Rice. 3. Corner joints

Branches

When branching, a beam suitable at a right or oblique angle in most cases is superficially joined to another beam. In normal cases, a joint on the trunnions is used, and in secondary structures, the joint "in the paw" is also used. In addition, beams made of timber 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 timber. The trunnions have a length in most cases from 4 to 5 cm. The groove for the trunnion is made 1 cm deeper so that the compression force is transmitted not through the section of the trunnion, but through a large area of ​​​​the remaining section of the bars.

When arranging trunnions, normal trunnions are distinguished, passing through the entire width of the beam, and protruding(hemp) pins, which are used for connections at the ends of the bars (Fig. 4). If the bars in the connection do not fit at right angles to each other, for example, at the corner struts, then the trunnion at the strut must be made at right angles to the horizontal (or vertical) structural element (see Fig. 4).

Rice. 4. Pin connections

When installing trunnions in wooden beams and girders, the trunnion must bear the entire load. It is more advantageous to make such connections using beam shoes from 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 docking point. In addition, the cross section of the beam is not weakened by the trunnion holes.

Cross connections

Wooden beams can intersect in the same plane or with offset planes and be overhead or support. Bars intersecting in the same plane can intersect "IN THE LAPU" if the weakening of the section does not play any role (Fig. 5). Intersecting overhead thresholds on the support beams, it is desirable to connect round dowels (pins) from solid wood or from steel with a length of 10 to 12 cm (Fig. 6).

Rice. 5. Connection "in the paw"

Rice. 6. Connection with round dowels (pins)

The beams joining on the side receive good support on the pole if their connection is made “In the groove” (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 an immovable connection, which is fixed with a screw bolt.

Rice. 7. Groove connection

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

Rice. 8. Insert rafter leg

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

Rice. 9. Steel shoe connection

cuts

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. According to the number and position of the force-transmitting planes, a frontal cut, a cut with a tooth, and a double front cut with a tooth are distinguished.

At frontal cutting(also called a frontal stop), the receiving beam has a wedge-shaped cutout that matches the shape of the end of the compressed rod (Fig. 10). The frontal plane should pass at an angle dividing the obtuse outer corner of the cut in half. The fastening bolt must also have the same direction, guaranteeing the joint from lateral displacement. To mark the cut, parallels are drawn at the same distance from the sides of the corner, 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 cutting

Under the action of a compressive force, the wood lying in front of the frontal part of the compressed rod works on slice(see fig. 10). Since the permissible stress on the cut of wood along the fibers is relatively small (0.9 MN / m 2), the plane of the wood in front of the cut edge (cut plane) must be large enough. Since, in addition, cracking due to shrinkage should be taken into account, with rare exceptions, the length of the cut plane should not be less than 20 cm.

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

Rice. 11. Serrated notch

double cut consists, as a rule, of a frontal cut in combination with a toothed cut (Fig. 12). The direction of the cutting planes is similar to that used for each of the cuttings of this combination. However, the notched cut in this case must be at least 1 cm deeper so that its cut plane is below the cut plane of the frontal cut. The fastening bolt should run parallel to the front of the notch approximately midway between the bisector and the top of the acute joint angle.

Rice. 12. Double notch

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

Pin and bolt connections

In the case of pin and bolt connections, wooden beams or boards that are in contact with the sides are connected by cylindrical connecting elements, such as rod dowels, bolts with countersunk heads and nuts, ordinary bolts with nuts. These rod dowels and bolts should prevent the wooden elements from moving in the connection plane, which is also called the shear plane. In this case, forces act perpendicular to the axis of the rod dowel or bolt. Dowels and bolts at the same time work on bending. In connected wooden elements all efforts are focused on inner surface 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 with rod dowels

In one connection, many shear planes can be located next to each other. According to the number of cut planes that are connected by the same connecting elements, single-cut, double-cut and multi-cut dowel and bolted connections are distinguished (Fig. 14). According to DIN 1052, single shear load-bearing connections with dowel pins must have at least four dowel pins.

Rice. 14. Bolted connections

For bolted connections, mainly bolts with nuts made of steel with a normalized diameter of 12, 16, 20 and 24 mm are used. In order to prevent the head and nut of the bolt from cutting into the tree, strong steel washers should be placed under them. The minimum dimensions of these washers are given for various diameters bolts in DIN 1052 (Table 2).

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

Rice. 15. Minimum distances in case of rod dowels and hidden head bolts

Rice. 16. Minimum distances in case of bearing bolts

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

Also, the bolt holes should match the diameter of the bolts well. Do not increase the diameter of the hole in comparison with the diameter of the bolt by more than 1 mm. With bolted connections, it is bad when the bolt sits freely in the hole. It is also bad if, due to the shrinkage of the wood, the clamp of the bolt in the hole gradually weakens. In this case, a play appears in the shear plane, which leads to even greater pressure of the bolt shaft on the boundary planes of the hole walls (Fig. 17). Due to the flexibility associated with this, 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 when bolted

Dowel connections

Dowels are fasteners made of hard wood or metal, which are used together with bolts to connect smoothly joined wooden elements (Fig. 18). They are positioned in such a way that they evenly act on the surface of the elements to be joined. In this case, the transmission of forces is carried out only through the dowels, while the bolts provide a clamping action in the connection so that the dowels cannot tip over. Laths made of flat or profiled steel are also attached to wooden elements using dowels. For this, one-sided dowels or flat steel dowels are used. Dowels are various forms and types.

Rice. 18. Connecting wooden elements with dowels and bolts

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

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

Each dowel, as a rule, should correspond to one bolt with 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 are diameters from 50 to 165 mm. In the drawings, the size of the dowels is indicated by symbols (Table 4).

Table 3. Minimum dimensions in dowel connections
Outer diameter d d in mm	Bolt diameter d b in mm	Distance between dowels/distance from dowel to element end, 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 push-in dowels type D.

Table 4. Drawing symbols for special type 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 dowel placement it is necessary to adhere to certain distances of the dowels between themselves and from the edges of the wooden elements. These minimum distances according to DIN 1052, they depend on the type of dowel and its diameter (see table. 3).

Bolts with dowel nuts are almost always driven 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 about 1 mm into the wood. For dowel connections, the nuts on the bolts must be re-tightened a few months after installation so that their tightening effect remains even after the wood has dried. They talk about a connection with a constant transmission of force.

Bearing pin connections

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

Single shear dowel joints 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 shaft of the hole and can bend with too much force. Since shear forces also occur in the connecting seam in the body of the nail, this sectional plane is called the shear plane. In the case of paired joining of plank rods on the planes of the main beam, there are two single-cut dowel joints opposite each other.

Rice. 20. Single shear dowel connection

At double shear dowel joints the nails pass through three connected wooden elements (Fig. 21). Nails have two cut planes, since they are loaded in both connecting seams with the same directed force. Therefore, the bearing capacity of a double-shear loaded nail is twice that of a single-shear nail. In order for the double-cut dowel joints to not disperse, half of the nails are hammered on one side, and the other half on the other. Double-cut dowel joints are mainly used if freely supported trusses consist entirely or mainly of boards or beams.

Rice. 21. Double-cut dowel connection

Minimum timber thicknesses and minimum nailing depth

Since thin wooden elements easily split when hammering nails, 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 minimum thicknessesa(Fig. 22). They depend on the diameter of the nail. With pre-drilled nail joints, the minimum thicknesses of the wood can be less than with simple nailing, as there is less risk of cracking.

Rice. 22. Minimum thickness and depth of driving

The distance of the tip of the nail 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 12d n. 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 bearing capacity of the nails decreases. If the nails have a driving depth of less than half that required, then they cannot be taken into account for the transmission of forces.

Minimum spacing between nails

Fixing formwork, battens and fillets, as well as rafters, battens, etc. acceptable with less than four nails. However, in general, at least four nails are required for each seam or multi-shear nail joint intended for force transmission.

The uniform arrangement of these nails on the plane of the connection is made using nail lines(Fig. 23). In order for two nails located one after another not to sit on the same fiber, they are displaced relative to the point of intersection of mutually perpendicular nail lines by the thickness of the nail in both directions. In addition, minimum distances must be observed. They depend on whether the direction of the force is parallel or across the fibers. Further, it is necessary to monitor whether the ends of the rods or the edges of the wood are loaded by the force acting in the joint 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 with a single shear connection

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

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

Rice. 24. Minimum distances between nails for double-cut joint

Nail connection device

When making nail joints, 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 junction are not damaged. For the same reason, the protruding ends of the nails can only be bent in a special way. This should only happen perpendicular to the fibers. For drawing the arrangement of nails, as a rule, suitably drilled templates from thin plywood or gestures. In the case of plywood templates, holes are made of such a diameter that nail heads can pass through them. In the case of tin templates, the locations of the nails are marked with a brush and paint.

Nail connections with steel plates

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

Overlays on the outside, as a rule, have pre-drilled holes (Fig. 25). They are superimposed over the connection of beams or boards to the butt and nailed with the appropriate number of wire or special nails. At embedded overlays with a thickness of at least 2 mm holes for nails must be drilled simultaneously in the wooden elements and in the overlays. In this case, the diameter of the holes must correspond to the diameter of the nail. Embedded linings less than 2 mm, of which there may be several at the junction, can be pierced with nails without pre-drilling (Fig. 26). Such connections may only be made with specially designed spline tools and only on the basis of special approval from the authorities.

Rice. 25. Connection with a perforated steel plate-lining

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

Connections with nail gussets

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

Rice. 27. Connection with a nail gusset

In this case, 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 and edges.

Nail gussets must be placed symmetrically on both sides and, using a suitable press, pressed into the wood so that the nails sit in the wood for their entire length. Hammering of nail gussets with a hammer or the like is unacceptable.

Fastening with the help of 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 working area of ​​\u200b\u200bthe connection of the nail gusset is of primary importance (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 minimum width of 10 mm.

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

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