Draw the connection of parts with a stud, screw and bolt. Bolt connection manual

Bolts, nuts, studs and screws are usually produced by special factories that supply all enterprises with these parts. Therefore, images of fasteners are found mainly in assembly drawings, where they are shown in connection with other parts and with each other.

In this case, the following types of images of these parts and their connections may occur:

constructive (detailed images), when the shape of parts or their connections is conveyed without significant deviations from the natural one (Fig. 9.15, a, c; rice. 9.16; rice. 9.17, c, e, rice. 9.18);
simplified when the images do not retain many details of the shape of the parts and their connections (Fig. 9.15, G; rice. 9.18, and; rice. 9.19, a, c, d, g);
conditional, when the concept of parts and their connections is conveyed schematically (Fig. 9.19, b, d, f, h).

GOST 2.315–68 establishes simplified and conventional images of fasteners on assembly drawings and drawings common types all industries and construction, some of which are shown in Fig. 9.19. A simplified or conventional image is chosen depending on the purpose and scale of the drawing. In this case, fasteners whose rod diameters in the drawing are 2 mm or less are depicted conventionally. The size of the image should give a complete picture of the nature of the connection.

Threaded connections on assembly drawings are usually drawn according to relative sizes. The size of the individual connection elements is determined depending on the outer diameter of the thread.

The dimensions of fasteners are not indicated on assembly drawings.

The necessary data is contained in the designation, which is recorded in the specification.

Bolted connections

Simplifications consist in not depicting chamfers on hexagonal and square bolt heads and nuts I, and also on the rod II. This means that the lines that represent the chamfers disappear. Doesn't show gap III between the bolt shank and the hole in the parts to be joined 1 And 2. In Fig. 9.16 it is highlighted with fill.

In addition, the thread is shown along the entire length of the bolt shaft (Fig. 9.15, d), and is not limited to its size l 0, as is the case in reality (Fig. 9.15, A – V) (IV). The image of the thread is also not shown in a view perpendicular to the axis of the rod, i.e. do not draw 3/4 of the circle with a thin line (see Fig. 9.15, G) (V). The same applies to simplified images of studs and screws.

To the drawing in Fig. 9.15, G easier to understand, its formation is shown in stages. First, a bolt is shown and above it are two parts to be connected. 1 And 2 (see Fig. 9.15, A), then the bolt is shown in the holes of these parts, and above them there is a washer 5 (see Fig. 9.15, b). In Fig. 9.15, the washer is put on the bolt 3, and above them there is a nut shown 4. At the same time, in Fig. 9.15, A chamfers are shown on the head and shaft of the bolt, and in Fig. 9.15, b they are no longer shown, but the gap between the bolt shank and the holes in the parts shown is shown. In Fig. 306, V this gap is no longer shown, but the chamfer on the nut is shown.

Rice. 9.15.

Completed simplified drawing bolted connection shown in Fig. 9.15, G. It complies with GOST 2.315–68.

Please note that the lines of the invisible contour when depicting the nut and washer are not drawn (see Fig. 9.15, G).

When drawing a nut and a bolt head, take the side of the hexagon equal to the outer diameter of the thread. Therefore in the main image vertical lines, limiting the middle edge of the nut and bolt head, coincide with the lines of the outer diameter of the thread.

Examples of symbols for bolts, nuts and other fasteners are given in Chapter. 7 (see 7.3).

The dimensions by which the elements of a bolted connection are drawn are usually calculated depending on the outer diameter of the thread from the ratios shown in Fig. 9.15. They are called relative.

Examples of determining relative dimensions for a structural image of a bolted connection with M30 threads (d = 30 mm).

The diameter of a circle circumscribed around a hexagon is D=2d=(2 30) = 60 mm; bolt head height h= 0.7 = 0.7 30 = = 21 mm; length of cut part l 0 = 2d+ 6 = 2 30 + 6 = 66 mm; nut height N = 0,8d 30 = 24 mm; bolt hole diameter d 0 =1,1 d= 1.1 30 = 33 mm; washer diameter D m = 2.2 d= 2.2 30 = = 66 mm; washer height S = 0.1 d= 0.15 30 = 4.5 mm.

Relative sizes for depicting a simplified connection are calculated using the same ratios.

Hairpin connections

The formation of a drawing of a hairpin connection is shown in stages in Fig. 9.17.

First, a hole for the thread is drilled in the part and a chamfer is made (see Fig. 9.17, A), the thread is cut with a tap (see Fig. 9.17, b), pin shown 3 (see Fig. 9.17, V). The pin is screwed into the hole. Above it is the part to be connected, which has a smooth hole (see Fig. 9.17, G). A part is put on the free end of the pin 2, and on top there is a washer (see Fig. 9.17, d). Washer 4 put on a stud, nut 5 is shown above (see Fig. 9.17, e), which is screwed onto stud 3 (see Fig. 9.17, and).

Rice. 9.16.

Rice. 9.17.

Nut 5 and washer 4 are depicted in a simplified manner, as in a bolted connection, i.e. without chamfers.

The line defining the thread boundary at the lower end of the stud is drawn at the level of the surface of the part in the constructive image 1, into which the pin is screwed.

Notice how the threaded rod is depicted screwed into the hole (see Fig. 9.17, Where). This is discussed in Chap. 7, and the corresponding images are shown in Fig. 7.13.

In Fig. 9.17, g shows a simplified drawing of a hairpin connection. It does not show the chamfers, the gap between the pin rod and the hole in the part being connected, and the end of a blind threaded hole that is not filled with threads, shown in Fig. 9.17, b–f, where, for clarity of the nature of the connections, they are shown when they first appear.

The relative dimensions for drawing a stud connection are calculated depending on the thread diameter according to the ratios shown in Fig. 9.17.

Examples of symbols for studs are given in 8.1.

Screw connections

There is no nut in the screw connection. A blind hole with a thread and the threaded part of the screw are drawn in the same way as in a stud joint. Only in structural images the thread boundary on the rod is located above the parting line of the parts being connected.

Structural connections with screws are shown in Fig. 9.18. If the screws have a slot (slot) for gripping with a screwdriver, it is conventionally depicted as one solid thick line. In the top view, it is carried out at an angle of 45° (see Fig. 9.18).

Rice. 9.18.

Simplified images of screw connections are shown in Fig. 9.10 and 9.19, d, f.

Target: study and learn to apply in practice the rules for depicting threads and threaded connections; execution of assembly drawings and specifications.

Zadanie:

Prepare specifications for the assembly drawing.

Apply the required dimensions.

Theoretical information

Thread – a surface formed by the helical movement of a flat contour along a cylindrical or conical surface.

Constructing a helical surface in a drawing is a long and complex process, therefore, in product drawings, threads are depicted conditionally, in accordance with GOST 2.311–68. The helix line is replaced by two lines - a solid main line and a solid thin line.

Threads are divided according to their location on the surface of the part into external and internal.

Figure 1 – Conventional image of the thread on the rod

The external thread on the rod (Fig. 1) is depicted by solid main lines along the outer diameter and solid thin lines along the internal diameter, and in images obtained by projection onto a plane perpendicular to the axis of the rod, a thin line is drawn along ¾ of the circle, and this line can be open anywhere (it is not allowed to start a solid thin line and end it on the center line). The distance between the thin line and the solid main line should not be less than 0.8 mm and greater than the thread pitch, and the chamfer is not shown in this view. The thread boundary is applied at the end of the full thread profile (before the start of the run) with a solid main line, if it is visible. If necessary, the thread run-out is depicted as a solid thin line.

Figure 2 – Conditional image threads in the hole

Internal thread - depicted as a solid main line along the internal diameter and a solid thin line along the external diameter (Fig. 2). If, when depicting a blind hole, the end of the thread is located close to its bottom, then it is allowed to depict the thread to the end of the hole.

Figure 3 – Conventional image of the thread assembly

On cuts threaded connection in the image on a plane parallel to its axis in the hole, only that part of the thread is shown that is not covered by the thread of the rod (Fig. 3).

Hatching in sections and sections is carried out to a solid main line, i.e. to the outer diameter of the male thread and the internal diameter of the female thread.

Initial data – fig. 4 and table. 1.

Execution example – fig. 8.

BOLT CONNECTION

Fastening two or more parts using a bolt, nut and washer is called bolted connection(Fig. 4). For the passage of the bolt, the parts to be fastened are smooth, i.e. without thread, coaxial cylindrical holes of larger diameter d 0 than the diameter of the bolt. A washer is put on the end of the bolt protruding from the fastened parts and a nut is screwed on.

When drawing a bolted connection, the design dimensions of the bolt, nut and washer are taken from the relevant standards. Bolt – GOST 7798-70, version 1 (Table 2), washer – GOST 11371-78, version 1 (Table 7), nut – GOST 5915-70, version 1 (Table 6).

Figure 4 – Bolted connection

To determine the bolt length l it is necessary to create an assembly dimensional chain. Figure 4 shows an assembly dimensional chain expressing the dimensional connections of a bolted connection. This dimensional chain allows you to determine the length of the bolt l, while ensuring the necessary thread reserve when the end of the bolt comes out of the nut (size f). Analytically, this dimensional chain can be represented by the equation:

where is the thickness of the parts to be connected;

– thickness of the washer;

– nut height;

– thread stock, ,

where P is the thread pitch (Table 2).

The quantities are known; and are given in the relevant standards and are selected depending on the bolt diameter d; calculated depending on the thread pitch P.

The diameter of the bolt holes is calculated using the formula.

The internal diameter of the bolt thread is .

The resulting size is rounded to the nearest bolt length according to table 3. The thread length is determined using the same table l 0 .

SCREW CONNECTION

Using fastening screws, you can fasten two or more parts. To do this, a threaded hole is made in the last of them, and smooth coaxial holes with a diameter of d 0 , larger than the screw diameter. The screw passes freely through the smooth holes of the parts being fastened and is screwed into the threaded hole of the last of them (Fig. 5).

Figure 5 – Screw connection

Depth l 1 screwing in of the screw depends on the material of the part and is assumed to be equal to:

To calculate the length of the screw, it is necessary to create an assembly dimensional chain (Fig. 5). Analytically, this dimensional chain can be expressed by the equation:

– thickness of the attached part;

– screw head height;

– length of the screwed part of the screw.

The size obtained as a result of calculation is rounded to the nearest screw length according to the size range of the corresponding standard (pages 11-12).

When drawing the connection of parts using screws, the design dimensions of the screws are taken from the corresponding standard (screws according to GOST 1491-72 - table 4, screws according to GOST 17475-72 - table 5). The slots of the screw heads on assembly drawings, in top (or left) views, are shown at an angle of 45 degrees to the drawing frame in accordance with GOST 2.315-68. The spline dimensions are taken according to GOST 24669-81 in Table 8.

The diameter of the hole in the attached part is .

The diameters of the threaded hole for the screw: – thread diameter, – hole diameter.

The dimensions of countersinks for screws with semi-countersunk, countersunk and cylindrical heads are taken according to GOST 12876-67 in tables 11, 12, depending on the nominal thread diameter.

STUD CONNECTION

Fastening two or more parts is carried out using a stud, nut and washer (Fig. 6). It is used instead of a bolt hole when it is impractical to make a through hole in one of the parts being connected due to its significant thickness or due to lack of space for the bolt head.

Figure 6 – Hairpin connection

First, a hole for the stud is drilled, then a chamfer is made, after which the thread is cut (the socket for the stud). On the coupling end of the pin, other parts are put on, fastened to the first one, having smooth coaxial cylindrical holes of a larger diameter d 0 than the diameter of the pin. A washer is put on the end of the stud protruding from the parts being fastened and a nut is screwed on (Fig. 6).

When drawing a connection with a stud, the design dimensions of the stud, nut and washer are taken from the relevant standards. Stud – GOST 22032-76, GOST 22034-76, GOST 22038-76, version 1 (Table 9), washer – GOST 11371-78, version 1 (Table 7), nut – GOST 5915-70, version 1 ( table 6).

When choosing a hairpin, you need to pay attention to the fact that the length l 1 screw-in (mounting) end depends on the material of the part into which it is screwed:

To determine the length of the nut end of the stud, it is necessary to create an assembly dimensional chain. In Fig. Figure 6 shows an assembly dimensional chain expressing the dimensional connections of a pin connection. This dimensional chain allows you to determine the length of the nut end of the stud, providing the necessary thread supply when the end of the stud exits the nut (dimension f).

Analytically, this dimensional chain can be represented by the equation:

where: – thickness of the attached part;

– thickness of the washer;

– nut height;

– thread reserve when the stud comes out of the nut, ,

Bolt connection

Task 1. On an A3 sheet of paper, draw a bolt according to actual dimensions, a connection - according to conditional dimensions.Take the bolt according to GOST 7798-70. Place a washer under the nut in accordance with GOST 11371-68. Take the initial data from Table 1.1. An example of task 1 is shown in Fig. 1.3.

Table 1.1

Initial data for constructing a bolt connection

Option	d , mm bolt diameter	p , mm thread pitch	Thickness parts to be fastened		Scale
Option	d , mm bolt diameter	p , mm thread pitch	m	n	Scale

1.1. Image of a bolted connection (Fig. 1.1)

On a sheet of A3 drawing paper, mark the locations for the image of the bolt, nut and connection.

At the location of the connection image, the location of the projections is determined, center lines are drawn and the diameter of the bolt is indicated with thin lines.

In the main view of the image, the base of the bolt head is outlined. The dimensions of the fastened parts are set off from it m And n, washer thickness S = 0,15d, nut height N = 0,8d and thread exit beyond the nut k = (0.25…0.5) d or (2…4) r. Then draw a line defining the height of the nut head.

In the top view, circles are drawn:

d– outer thread diameter (bolt diameter);

d 1 – 0,85d– symbol of the thread on the end of the bolt;

D = 2d– diameter of the circle for constructing the hexagon of the nut and bolt head;

D w = 2.2 d– diameter of the washer.

From the top view main view and the left view projectively transfer the dimensions of the faces of the nut and bolt head, the diameter of the washer D w, and thread symbol d 1.

Then determine the length of the threaded part of the bolt: l 0 = 2d + 2p. The obtained value is agreed upon with GOST and noted on the drawing. Determine the size of the chamfer C = 0,15d and apply it on images of the end of the bolt.

Determine the hole diameter d 0 = 1.1 d in detail m And n and put it on the drawing. The sequence of drawing chamfers on the hexagonal head of a bolt is set out in paragraphs. 1.2, and the nuts in paragraph 3.3.

Details m And n depicted in cross-section. The contours of these parts are determined in the drawing, and what is included in the cut is shaded (fasteners on assembly drawings are shown without a cut).

Apply dimensions. The following dimensions must be entered on this assembly drawing:

d– bolt thread diameter;

l– bolt length;

l 0 – bolt thread length;

S– turnkey size.

Dimensions l, l 0 , and S consistent with GOST.

Then the extra lines are removed from the drawing and outlined.

Rice. 1.1. Constructing a bolt connection using conditional relationships

1.2. Bolt drawing

It is performed in accordance with GOST 7798-70 in the following sequence (Fig. 1.2).

1.2.1. According to the specified values of the outer diameter of the thread d and calculated bolt length l from the tables of GOST 7798-70 (Table 1.2) determine the remaining dimensions of the bolt (head height N, circumscribed circle diameter D, radius headrest R, length of the threaded part of the rod l 0).

1.2.2. Draw the contours of the images of the bolt: the main view, the top view and the left view. N.B.!: Drawing the view must begin with the center lines.

1.2.3. In the view on the left, draw a circle with a diameter D 1 = 0,9s(Where S- turnkey size). This circle is the line of intersection of the end of the bolt head with the chamfer.

1.2.4. Mark the points IN""" 1 , IN""" 2 , IN""" 3 , IN""" 4 located on circle D 1 and determine their positions on the main view ( IN"" 1 and IN"" 3 ) and top view ( IN" 2 and IN" 4).

1.2.5. From points IN"" 1 IN" 3 and IN" 2 IN" 4 draw straight lines at an angle of 30° to the end of the bolt head, which, at the intersection with the corresponding edges of the bolt head, determine the points A"" 1 , A"" 4 and WITH 2 ," WITH" 5 .

Using a line passing through points A"" 1 , A"" 4 , find the points A"" 2 and A"" 3 .

1.2.6. Through dots A"" 2 , WITH"" 2 , A"" 3 draw a circular arc.

1.2.7. Arc of a circle A"" 2 WITH"" 2 A"" 3 allows you to define points M 0 and N 0 straight line on which the centers of K are located 0 arcs of circles passing through the points A"" 1 , A"" 2 and A"" 3 , A"" 4 .

In the top view, horizontal projections of these curves are drawn in the form of circular arcs passing through points A" 1 , WITH" 1 , A" 2 and A" 1 WITH" 6 A" 6. After this, indicate the threaded part of the bolt shaft, draw chamfers (with × 45°), draw a fillet r(smooth transition from the bolt shaft to its head).

At the final stage of drawing up the bolt, its dimensions are applied (according to GOST 7798-70).

Rice. 1.2. Sequence of drawing a standard bolt version 1

Table 1.2

Hex head bolts of normal accuracy (GOST 7798-70)

d	S	N	D , no less	R	l	l o
				0,25...0,6
				0,40... 1 ,1	28...100
				0,6...1,6	32...200
				0,6...1,6	35...260
				0,6...1,6	45...300
			3 3, 3	0,8...2,2	55...300
				0,8...2,2	65...300
				1,0 … 2,7	75...300
				1,0...3,2	90...300
				1,2. . .3,3	105...300
				1,6...4,3	1 15...3 0 0

Notes: 1. Length 1 is selected within the specified limits from the range: 8, 10, 12, 14, 16, (18), 20, (22), 25, (28), 30, (32), 35, (38) , 40, 45, 50, 55, 60, 65 , 70, 75, 80, (85), 90, (95), 100, (105), 110, (115), 120, (125), 130, 140 , 150, 160, 170, 180, 190, 200, 220, 240, 260, 280, 300.

2. An example of a symbol for a bolt with a hex head, thread diameter 12 mm, length 60 mm in version 1, with a large thread pitch and dimensions in accordance with GOST 7798-70: Bolt M12x 60 GOST 7798-70. The same, with a fine thread pitch of 1.25 mm: Bolt M12 x 1.25 x 60 GOST 7798-70.

Rice. 1.3. Example of task 1

Among detachable connections greatest distribution received threaded ones. These include bolted, stud and screw connections, shown in Figure 209. The parts of these connections - bolts, screws, studs, nuts and washers - have the shape, dimensions, etc. established by the standard. symbols. Using these designations, you can find the dimensions of fasteners in the corresponding standards tables. How to do this was shown using the example of a bolt drawing.

Images of fasteners can be found mainly in assembly drawings. In these drawings, bolted, stud and screw connections are drawn according to relative sizes. This means that the size of individual elements is determined depending on the outer diameter d of the thread. As a result, the work on completing the drawing is accelerated.

The dimensions of fasteners are not indicated on assembly drawings. But how, in this case, can you determine which bolt or stud is included in the connection?

The necessary data is recorded in specifications. We will get to know her later. Now let's look at the images of the main threaded connections.

32.1. Image of bolted connections. This connection is shown in Figure 216. In the parts that need to be connected (part 1 and part 2), holes are drilled with a slightly larger diameter than the diameter of the bolt.

It is recommended to draw drawings of fastening connections in a simplified manner (Fig. 217, d). This is as follows. Chamfers on hexagonal and square heads of bolts and nuts, as well as on the rod, are not shown. It is allowed not to show the gap between the bolt shaft and the hole in the parts being connected.

To make the drawing presented in Figure 217, d easier to understand, we will show the formation of a bolted connection in stages. First, a bolt is shown and above it are two parts to be connected (Fig. 217, a). Then the bolt is shown in the holes of these parts, and above it is a washer (Fig. 217, b). In Figure 217, a washer is put on a bolt, and a nut is shown above it. The completed drawing of the bolted connection is shown in Figure 217, d.

Please note that the parts to be connected (1 and 2) are shaded in different directions.

Rice. 216. Bolted connection

Rice. 217. Simplified image of a bolted connection

Bolts in the assembly drawing are shown uncut if the cutting plane is directed along their axis. Nuts and washers are also shown uncut.

The specifications for bolts indicate the diameter and type of thread, the length of the rod and the standard number1. Record Bolt M12 x 1.25 U-60 means: bolt with metric thread (diameter) 12 mm, pitch 1.25 mm (small), rod length 60 mm.
1 In the textbook, to simplify recording here and below, the standard number is not given for other fasteners.

For a nut, indicate the diameter and type of thread. Record screw M16 means: a nut with a metric thread, having a diameter of 16 mm, the thread pitch is large. For washers, indicate the diameter of the bolt. Record Washer 12 means: washer for a bolt with a diameter of 12 mm.

You will draw bolted connection elements using relative dimensions. They are determined depending on the outer diameter of the thread according to the relationships shown in Figure 217. Consider an example of determining the relative dimensions for a bolted connection with an M20 thread (d = 20 mm):
diameter of the circle circumscribed around the hexagon, D = 2d(2 x 20 = 40 mm);

bolt head height h = 0.7d(0.7 x 20 = 14 mm);
for the threaded part l0 ~ 2d + 6(2 x 20 + 6 = 46 mm);
nut height H = 0.8d(0.8 x 20 = 16 mm);
bolt hole diameter d = 1.1d(1.1 x 20 = 22 mm);
washer diameter Dsh = 2.2d (2.2 x 20 = 44 mm);
washer height S = 0.15d(0.15 x 20 = 3 mm).

Using these dimensions, you can draw a bolted connection.

1. Depending on what value determine the relative dimensions of a bolted connection?
2. When making a cut on the assembly drawing, the cutting plane passed along the axis of the bolt, nut and washer. Do they need to be hatched?
3. Is it possible in Figure 217, d not to show the gap between the bolt shaft (part 5) and the holes in the connected parts 1 and 2?
4. Decipher the designation: “Bolt M16 x 70” and “Nut M20”.
5. What is the large circle depicted in the top view (Fig. 217, d)?
6. Name the number of the part shown in the top view with a hexagon (Fig. 217, d).

59. Draw a sketch of the bolted connection, guided by the example in Figure 217, d Thread diameter d is 10 mm. The thickness of each of the connected parts is 15 mm. The length l of the bolt shaft is 45 mm.

32.2. Image of stud connections. A stud is a rod that has threads on both ends. With one end of the pin, the entire length of the thread is screwed into a blind (non-through) threaded hole in part 1 (Fig. 218). A nut is screwed onto the other end, under which a washer is placed. In this way, the parts to be fastened are pressed together (parts 1 and 2). The hole in part 2 has a slightly larger diameter than the pin (Fig. 218).

Rice. 218. Hairpin connection

Let us show in stages the formation of the hairpin joint shown in Figure 219, g.

First, the part shows a hole for the thread and a drill above it (Fig. 219, a), and then a hole with a thread and on top a tap with which the thread is cut (Fig. 219, b). Above the hole (Fig. 219, c) a pin is shown, which is screwed into the hole (Fig. 219, d), and the part being connected is shown above.
In Figure 219, e, the washer is put on a stud; the nut is shown above. And finally (Fig. 219, g), a drawing of a hairpin connection is shown.

The nut and washer, as in a bolted connection, are depicted in a simplified manner, i.e., without chamfers. The chamfers on the hairpin are also not shown.

The line defining the thread boundary at the lower end of the stud is always drawn at the level of the surface of the part into which the stud is screwed (detail 1, Fig. 219, g).

Look carefully at how a threaded rod is depicted screwed into a hole. The thread in the hole is shown only where it is not closed by the end of the rod (Fig. 220, a). The bottom of the blind hole is shown unfilled with a rod. For clarity, the lower part of the hole is highlighted in brown.

At the end of the hole there is a conical recess obtained from the drill (see Fig. 220, a). It is drawn with an angle of 120° at the apex, but the size of this angle is not indicated. Do not make the mistake shown in Figure 220, b, where the diameter of the recess turns out to be greater than the diameter of the hole, which cannot be the case.

Rice. 219. Simplified image of a hairpin connection

The shading is brought to a solid thick line (Fig. 221, a), and not to a thin one, as shown in Fig. 221, b.

You will calculate the relative dimensions for drawing the stud connection depending on the thread diameter according to the ratios shown in Figure 219.

Designation Hairpin M10 x 60 should be understood as follows: the stud has a metric thread, its diameter is 10 mm, length 60 mm (to the screwed end).

Take a look at this “graphic suitcase”. Look at the rich menu of all kinds of metal products there. Take a look at this “graphic suitcase”. Look at the rich menu of all kinds of metal products there. 1. Select from these three products that can securely fasten the parts shown in the upper left corner. 2. Determine the names of the selected parts and the name of the entire connection.

Among detachable connections, threaded ones are most common. These include: bolt, stud and screw. The parts of these connections - bolts, screws, studs, nuts and washers - have the shape, dimensions and symbols established by the standard.

Using these designations, you can find the dimensions of fasteners in the corresponding standards tables. We discussed how to do this in the last lesson. Bolt M 20x2x80 GOST Nut M 16 GOST Screw M 12x50 GOST - 72 Washer 12 GOST You can usually see images of fasteners on assembly drawings.

Image of a bolted connection In these drawings, the size of individual elements of threaded parts is determined depending on the outer diameter of the thread (d) In these drawings, the size of individual elements of threaded parts is determined depending on the outer diameter of the thread (d) Dimensions of fasteners are not indicated on assembly drawings Dimensions of fasteners not shown on assembly drawings

Let's look at the front section and top view of a bolted connection. In the parts that need to be connected, holes are drilled with a slightly larger diameter than the diameter of the bolt. In the parts that need to be connected, holes are drilled with a slightly larger diameter than the diameter of the bolt. Chamfers on hexagonal and square heads of bolts and nuts, as well as on the rod, are not shown. Chamfers on hexagonal and square heads of bolts and nuts, as well as on the rod, are not shown. They do not show the gap between the bolt shaft and the hole in the parts being connected. They do not show the gap between the bolt shaft and the hole in the parts being connected. Bolts, nuts and washers in the assembly drawing are shown uncut if the cutting plane is directed along their axis. Bolts, nuts and washers in the assembly drawing are shown uncut if the cutting plane is directed along their axis.

The elements of the bolted connection are drawn according to relative dimensions d = 20 mm thread diameter D = 2d, 2 x 20 = 40 mm diameter of a circle circumscribed around the hexagon h = 0.7d, 0.7 x 20 = 14mm height of the bolt head l o = 2d + 6, 2 x = 46mm for the threaded part H = 0.8d, 0.8 x 20 = 16mm nut height d o = 1.1d, 1.1 x 20 = 22mm bolt hole diameter D w = 2.2d, 2.2 x 20 = 44mm washer diameter S = 0.15d, 0.15 x 20 = 3mm washer height The thickness of each of the connected parts is 20 mm.
The specification for bolts indicates the diameter and type of thread, the length of the rod and the standard number Bolt M12x 1.25x60 means a Bolt with a metric thread with a diameter of 12 mm, pitch 1.25 mm (fine), rod length 60 mm Nut M16 means a nut with a metric thread having a diameter 16mm, large thread pitch Washer 12 means Washer for a bolt with a diameter of 12mm