A blind threaded hole is made in the following order: first, a hole of diameter d1 under the thread, then the lead-in chamfer is made S x45º (Fig. 8, A) and finally sliced internal thread d(Fig. 8, b). The bottom of the thread hole has a conical shape, and the angle at the apex of the cone φ depends on drill sharpening A. When designing, φ = 120º (nominal drill sharpening angle) is assumed. It is quite obvious that the depth of the thread must be greater than the length of the screwed-in threaded end of the fastener. There is also some distance between the end of the thread and the bottom of the hole. A, called "undercut".
From Fig. 9, the approach to assigning the dimensions of blind threaded holes becomes clear: thread depth h is defined as the difference in tie length L threaded part and total thickness H attracted parts (maybe
there may be one, or maybe several), plus a small supply of threads k, usually taken equal to 2-3 steps R threads
h = L – H + k,
Where k = (2…3) R.
Rice. 8. Sequence of making blind threaded holes
Rice. 9. Screw fastening assembly
Pull length L fastener is indicated in its symbol. For example: “Bolt M6x20.46 GOST 7798-70” – its tightening length L= 20 mm. Total thickness of attracted parts H calculated from the drawing general view(the thickness of the washer placed under the head of the fastener should also be added to this amount). Thread pitch R also indicated in the symbol of the fastener. For example: “Screw M12x1.25x40.58 GOST 11738-72” - its thread has a fine pitch R= 1.25 mm. If the step is not specified, then by default it is major (large). Lead-in chamfer leg S usually taken equal to the thread pitch R. Depth N threaded holes greater value h by the size of the undercut A:
N = h + a.
Some difference in calculating the dimensions of a threaded hole for a stud is that the screwed-in threaded end of the stud does not depend on its tightening length and the thickness of the parts being pulled. For the GOST 22032-76 studs presented in the assignment, the screwed-in “stud” end is equal to the diameter of the thread d, That's why
h = d + k.
The resulting dimensions should be rounded to the nearest larger integer.
Final image of a blind tapped hole with required sizes shown in Fig. 10. The diameter of the thread hole and the sharpening angle of the drill are not indicated in the drawing.
Rice. 10. Image of a blind threaded hole in the drawing
The reference tables show the values of all calculated values (diameters of threaded holes, undercuts, washer thicknesses, etc.).
Necessary note: the use of a short undercut must be justified. For example, if the part at the location of the threaded hole in it is not thick enough, and a through hole for the thread may break the tightness of the hydraulic or pneumatic system, then the designer has to “squeeze”, incl. shortening the undercut.
PARTS SUBJECT TO JOINT MECHANICAL TREATMENT
During the manufacture of machines, some surfaces of parts are not processed individually, but together with the surfaces of mating parts. The drawings of such products have special features. Without pretending to full review possible options, let us consider two types of such details found in tasks on the topic.
Pin connections
If in an assembly unit two parts are joined along a common plane and there is a need to accurately fix their relative position, then connecting the parts with pins is used. Pins allow you not only to fix parts, but also to easily restore their previous position after disassembly for repair purposes. For example, in the assembly of two body parts 1 And 2 (see Fig. 11) it is necessary to ensure the alignment of the borings Ø48 and Ø40 for the bearing units. The flanges are pressed using bolts 3 , and the once-adjusted alignment of the borings is ensured by two pins 6 . A pin is a precise cylindrical or conical rod; The hole for the pin is also very precise, with a surface roughness of no worse than Ra 0.8. Obviously, a complete match of the pin hole, the halves of which are located in different parts, is easiest to achieve if the two parts are first positioned in the required position, bolted together and a hole for the pin is made with one pass of the tool in both flanges at once. This is called co-processing. But such a reception must be specified in project documentation so that the technologist takes it into account when forming technological process assembly manufacturing. The joint machining of pin holes is specified in the design documentation in the following way.
The ASSEMBLY drawing specifies the dimensions of the holes for the pin, the dimensions of their location, and the roughness of the hole processing. The named sizes are marked with “*”, and in technical requirements The following entry is made in the drawing: “All dimensions are for reference, except those marked *.” This means that the dimensions along which holes are made on the assembled assembly are executive and they are subject to control. And in the drawings of the DETAILS, holes for the pin are not shown (and therefore are not made).
Bores with connector
In some machines, bored holes for bearings are located simultaneously in two parts with their parting plane located along the axis of the bearing (most often found in gearbox designs - the “housing-cover” connection). Bores for bearings are precise surfaces with a roughness no worse than Ra 2.5, they are made by joint processing, and in the drawings this is specified as follows (see Fig. 12 and 13).
In the drawings of EACH of the two parts, the numerical values of the dimensions of the surfaces processed together are indicated in square brackets. In the technical requirements of the drawing, the following entry is made: “Processing according to dimensions in square brackets should be carried out together with the detail. No...." The number refers to the designation of the drawing of the counter part.
Rice. 11. Specifying a hole for the pin in the drawing
Rice. 12. Boring with connector. Assembly drawing
Rice. 13. Specifying boring with a connector on the drawings of parts
CONCLUSION
After reading the process of creating a part drawing described above, a doubt may arise: do professional designers really work out every small detail so carefully? I dare to assure you – that’s exactly it! It’s just that when making drawings of simple and standard parts, all this is done in the designer’s head instantly, but in complex products - only this way, step by step.
BIBLIOGRAPHICAL LIST
1. GOST 2.102-68 ESKD. Types and completeness of design documents. M.: IPK Publishing House of Standards, 2004.
2. GOST 2.103-68 ESKD. Development stages. M.: IPK Publishing House of Standards, 2004.
3. GOST 2.109-73 ESKD. Basic requirements for drawings. M.: IPK Publishing House of Standards, 2004.
4. GOST 2.113-75 ESKD. Group and basic design documents. M.: IPK Publishing House of Standards, 2004.
5. GOST 2.118-73 ESKD. Technical Proposal. M.: IPK Publishing House of Standards, 2004.
6. GOST 2.119-73 ESKD. Preliminary design. M.: IPK Publishing House of Standards, 2004.
7. GOST 2.120-73 ESKD. Technical project. M.: IPK Publishing House of Standards, 2004.
8. GOST 2.305-68 ESKD. Images – views, sections, sections. M.: IPK Publishing House of Standards, 2004.
9. Levitsky V. S. Mechanical engineering drawing: textbook. for universities / V. S. Levitsky. M.: Higher. school, 1994.
10. Mechanical engineering drawing / G. P. Vyatkin [etc.]. M.: Mechanical Engineering, 1985.
11. Reference guide to drawing / V. I. Bogdanov. [and etc.]. M.:
Mechanical Engineering, 1989.
12. Kauzov A. M. Execution of drawings of parts: reference materials
/ A. M. Kauzov. Ekaterinburg: USTU-UPI, 2009.
APPLICATIONS
Annex 1
Assignment on topic 3106 and an example of its execution
Task No. 26
Example of task No. 26
Appendix 2
Common mistakes students when performing detailing
When depicting the thread on the rod In the front and left views, the outer diameter of the thread is shown with a solid main line, and the inner diameter is shown with a solid thin line (Fig. 1.6, a). In the view on the left, a chamfer is not depicted in order to be able to mark the internal diameter of the thread with a continuous thin line, open to one quarter of the diameter of the circle. Please note that one end of the circular arc does not reach the center line by approximately 2 mm, and its other end intersects the second center line by the same amount. The end of the cut part is shown as a solid main line.
When and image of thread in hole in the front view, the outer and inner diameters of the thread are shown with dashed lines (Fig. 1.6, b). In the view on the left, the chamfer is not shown, and the outer diameter of the thread is drawn as a continuous thin line, open to one quarter of the circle. In this case, one end of the arc is not completed, and the other crosses the center line by the same amount. Inner diameter threads are drawn as a solid main line. The thread boundary is shown with a dashed line.
In the section, the thread in the hole is shown as follows (Fig. 1.6, c). Outside diameter draw with a solid thin line, and the inner one with a solid main line. The thread boundary is shown by a solid main line.
The type of thread is conventionally designated:
M - metric thread (GOST 9150-81);
G - cylindrical pipe thread (GOST 6357-81);
T g - trapezoidal thread(GOST 9484-81);
S - thrust thread (GOST 10177-82);
Rd - round thread (GOST 13536-68);
R - external conical pipe (GOST 6211-81);
Rr - internal conical (GOST 6211-81);
Rp - internal cylindrical (GOST 6211-81);
K - conical inch thread(GOST 6111-52).
In the drawings, after designating the type of thread, (for example, M), the value of the outer diameter of the thread is written, for example, M20; then a fine thread pitch can be indicated, for example, M20x1.5. If the thread pitch is not indicated after the outer diameter, this means that the thread has a large pitch. The thread pitch is selected according to GOST.
When making drawings of threaded connections, the following simplifications are used:
1. do not depict chamfers on hexagonal and square heads of bolts, screws and nuts, as well as on its rod;
2. it is allowed not to show the gap between the shaft of a bolt, screw, stud and the hole in the parts being connected;
3. when constructing a drawing of bolted, screw, stud connections, do not draw invisible contour lines on the images of nuts and washers;
4. bolts, nuts, screws, studs and washers in the drawings of bolted, screw and stud connections are shown uncut if the cutting plane is directed along their axis;
5. When drawing a nut and a bolt head, a screw, take the side of the hexagon equal to the outer diameter of the thread. Therefore, in the main image, the vertical lines delimiting the middle edge of the nut and bolt head coincide with the lines outlining the bolt shank.
When making drawings of detachable connections, the most common following errors:
1. the thread on the rod in the blind hole is incorrectly marked;
2. no thread border;
3. the thread on the chamfer is shown incorrectly;
4. incorrectly labeled pipe thread;
5. The distance between thin and solid lines when depicting a thread is not maintained;
6. The connection of the internal and external threads (connection of the fitting to the pipe) is not made correctly.
Bolted connection
A bolt is a fastening threaded part in the form of a cylindrical rod with a head, part of which is threaded (Fig. 1.13).
The size and shape of the head allows it to be used for screwing a bolt using a standard wrench. Typically, a conical chamfer is made on the bolt head, smoothing out the sharp edges of the head and making it easier to use. wrench when connecting a bolt to a nut.
Rice. 1.13. Photo of a hex head bolt and a screwed nut.
The fastening of two or more parts using a bolt, nut and washer is called a bolted connection (Fig. 1.14) .
The bolted connection consists of:
§ parts to be connected (1, 2);
§ washers (3);
§ nuts (4),
§ bolt (5).
For the passage of the bolt, the parts to be fastened are smooth, i.e. without thread, coaxial cylindrical holes with a larger diameter 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.
Sequence of drawing execution bolted connection:
1. Depict the parts being connected.
2. Depicts a bolt.
3. Depict a puck.
4. Depict a nut.
IN educational purposes It is customary to draw a bolted connection by relative dimensions. The relative dimensions of the bolted connection elements are determined and correlated with the outer diameter of the thread:
§ diameter of a circle circumscribed around a hexagon D=2d;
§ bolt head height h=0.7d;
§ length of the threaded part lo=2d+6;
§ nut height H=0.8d;
§ bolt hole diameter d=l,ld;
§ washer diameter Dsh=2.2d;
§ washer height S=0.15d.
Exist Various types bolts that differ from each other in the shape and size of the head and rod, in the thread pitch, in manufacturing accuracy and in execution.
Hex head bolts have from three (Fig. 1.15) to five designs:
§ Version 1 – without a hole in the rod.
§ Version 2 – with a hole in the rod for a cotter pin.
§ Version 3 – with two through holes in the head, intended for cotter pinning with wire in order to prevent the bolt from self-unscrewing.
§ Version 4 – with round hole at the end of the bolt head.
§ Version 5 – with a round hole in the end of the bolt head and a hole in the rod.
When depicting a bolt in a drawing, two types are performed (Fig. 1.16) according to general rules and apply the dimensions:
Rice. 1.14. Bolted connection
1. bolt length L;
2. thread length Lo;
3. spanner size S ;
4. thread designation Md .
The height H of the head in the length of the bolt is not included.
Hyperbolas formed by the intersection of the conical chamfer of the bolt head with its faces are replaced by other circles.
A simplified image of a bolted connection is shown in Figure 1.17.
Rice. 1.15. Hex bolt version
Examples of bolt symbols:
1. Bolt Ml2 x 60 GOST 7798-70 - with a hex head, first design, with M12 thread, coarse thread pitch, bolt length 60 mm.
2. Bolt M12 x 1.25 x 60 GOST 7798-70 - with fine metric thread M12x1.25, bolt length 60 mm.
Hairpin connection
A stud is a fastener, the rod is threaded at both ends (Fig. 1.18).
A hairpin connection is a connection of parts made using a hairpin, one end of which is screwed into one of the parts being connected, and the attached part, a washer, and a nut are put on the other (see Fig. 1.19). Used to tighten and fix elements at a given distance metal structures with metric thread.
Rice. 1.20. Simplified illustration of a stud joint
Connecting parts with a pin is used when there is no room for a bolt head or when one of the parts being connected has a significant thickness. In this case, it is not economically feasible to drill a deep hole and install a long bolt. The pin connection reduces the weight of the structures.
The design and dimensions of the studs are determined by standards depending on the length of the threaded end l1 (see Table 1).
The drawing of the hairpin connection is carried out in the following sequence and according to the parameters indicated in Fig. 1.19:
1. Show a part with a threaded hole.
2. Depict a hairpin.
3. Draw an image of the second part to be connected.
4. Depict a puck.
5. Depict a nut
Examples of stud symbols:
1. Stud M8 x 60 GOST 22038-76 - with a large metric thread with a diameter of 8 mm, stud length 60 mm, designed for screwing into light alloys, length of the screwed end 16 mm;
2. Stud M8 x 1.0 x 60 GOST 22038-76 - the same, but with a fine thread pitch of -1.0 mm.
Screw connection
A screw is a threaded rod with a head whose shape and dimensions differ from the heads of bolts. Depending on the shape of the screw head, they can be screwed in with keys or screwdrivers, for which purpose a special slot (slot) for a screwdriver is made in the screw head (Fig. 1.21). Screw differs from a bolt by the presence of a slot (slot) for a screwdriver.
Rice. 1.22. Screw connection
Screw connection includes parts to be connected and screw and washer. In connections with countersunk screws and set screws, do not use a washer.
According to their purpose, screws are divided into:
§ fastening - used to connect parts by screwing a screw with a threaded part into one of the parts being connected.
§ installation - used for mutual fixation of parts.
In set screws, the rod is completely threaded and they have a cylindrical, conical or flat pressure end (Fig. 1.23).
Rice. 1.23. Set screws
Depending on the operating conditions, screws are manufactured (Fig. 1.24):
§ with a cylindrical head (GOST 1491-80),
§ semicircular head (GOST 17473-80),
§ semi-countersunk head (GOST 17474-80),
§ countersunk head (GOST 17475-80) with a slot,
§ with a keyed head and with corrugation.
In the drawing, the shape of a slotted screw is completely conveyed by one image on a plane, parallel to the axis of the screw. In this case they indicate:
1. thread size;
2. screw length;
3. length of the cut part (lo = 2d + 6 mm);
4. symbol of the screw according to the relevant standard.
Sequence of drawing a screw connection:
1. Depict the parts being connected. One of them has a threaded hole into which the threaded end of the screw is screwed.
Rice. 1.24. Types of screws
2. The cross-section shows the threaded hole partially closed by the threaded end of the screw rod. The other connecting part is shown with a gap existing between the cylindrical hole of the upper connecting part and the screw.
3. Depict a screw.
Examples of screw symbols:
1. Screw M12x50 GOST 1491-80 - with a cylindrical head, version 1, with M12 thread with a coarse pitch, 50 mm long;
2. Screw 2M12x1, 25x50 GOST 17475-80 - with a countersunk head, version 2, with a fine metric thread with a diameter of 12 mm and a pitch of 1.25 mm, screw length 50 mm.
Picture of nut and washer
screw - a fastener with a threaded hole in the center. It is used for screwing onto a bolt or stud until it stops in one of the parts to be connected.
Depending on the name and operating conditions, the nuts are hexagonal, round, wing, shaped, etc. Hexagonal nuts are most widely used.
Nuts are manufactured in three designs (Fig. 1.25):
Version 1 - with two conical chamfers;
version 2 - with one conical chamfer;
version 3 - without chamfers, but with a conical protrusion at one end.
The shape of the nut in the drawing is conveyed in two ways:
§ on the projection plane parallel to the nut axis, combine half of the view with half of the frontal section;
§ on a plane perpendicular to the nut axis, from the chamfer side.
The drawing indicates:
§ thread size;
§ size S Full construction;
§ nut designation according to the standard.
 |
Rice. 1.25. Nut shapes
Examples of nut symbols:
Nut M12 GOST 5915-70 - first version, with a thread diameter of 12 mm, large thread pitch;
Nut 2M12 x 1.25 GOST 5915-70 - second version, with fine metric thread with a diameter of 12 mm and a pitch of 1.25 mm.
A washer is a turned or stamped ring that is placed under a nut, screw or bolt head in threaded connections.
The flatness of the washer increases the supporting surface and protects the part from scuffing when screwing the nut with a wrench.
Round washers according to GOST 11371-78 have two designs (Fig. 1.26):
§ execution 1 - without chamfer;
§ version 2 - with chamfer.
The shape of a round washer is conveyed by one image on a plane parallel to the axis of the washer.
The internal diameter of the washer is usually 0.5...2.0 mm larger than the diameter of the bolt rod on which the washer is placed. The symbol of the washer also includes the thread diameter of the rod, although the washer itself does not have a thread.
Examples of washer symbols:
 |
Rice. 1.26. Shapes of washers
Washer 20 GOST 11371-78 - round, first version, for bolt with M20 thread;
Washer 2.20 GOST 11371-78 - the same washer, but of a second design.
For the purpose of protection threaded connection against spontaneous loosening under conditions of vibration and alternating load, the following is used:
§ spring washers according to GOST 6402-70;
§ lock washers with tabs.
Resolution State Committee USSR standards dated January 4, 1979 No. 31, the introduction date is setfrom 01.01.80
This standard establishes rules for indicating tolerances of shape and surface arrangement on drawings of products from all industries. Terms and definitions of tolerances for the shape and location of surfaces - according to GOST 24642-81. Numerical values of tolerances for the shape and location of surfaces are in accordance with GOST 24643-81. The standard fully complies with ST SEV 368-76.
1. GENERAL REQUIREMENTS
1.1. Tolerances of the shape and location of surfaces are indicated in the drawings by symbols. The type of tolerance of the shape and location of surfaces must be indicated in the drawing by signs (graphic symbols) given in the table.|
Tolerance group |
Type of admission |
|
| Shape tolerance | Straightness tolerance | |
| Flatness tolerance | ||
| Roundness tolerance | ||
| Cylindricity tolerance | ||
| Longitudinal profile tolerance | ||
| Location tolerance | Parallel tolerance | |
| Perpendicularity tolerance | ||
| Tilt tolerance | ||
| Alignment tolerance | ||
| Symmetry tolerance | ||
| Positional tolerance | ||
| Intersection tolerance, axes | ||
| Total tolerances of shape and location | Radial runout tolerance Axial runout tolerance Runout tolerance in a given direction | |
| Tolerance for complete radial runout Tolerance for complete axial runout | ||
| Shape tolerance of a given profile | ||
| Shape tolerance of a given surface |
2. APPLICATION OF TOLERANCE MARKINGS
2.1. When designating symbols, data on the tolerances of the shape and location of surfaces are indicated in a rectangular frame, divided into two or more parts (Fig. 1, 2), in which they place: in the first - a tolerance sign according to the table; in the second - the numerical value of the tolerance in millimeters; in the third and subsequent ones - the letter designation of the base (bases) or the letter designation of the surface with which the location tolerance is associated (clauses 3.7; 3.9).Crap. 1
Crap. 2
2.2. Frames should be made with solid thin lines. The height of numbers, letters and signs that fit into frames must be equal to the font size of the dimensional numbers. A graphic representation of the frame is given in mandatory Appendix 1. 2.3. The frame is positioned horizontally. If necessary, a vertical position of the frame is allowed. No lines are allowed to cross the frame. 2.4. The frame is connected to the element to which the tolerance relates with a solid thin line ending with an arrow (Fig. 3).
Crap. 3
The connecting line can be straight or broken, but the direction of the connecting line segment ending with an arrow must correspond to the direction of the deviation measurement. The connecting line is drawn away from the frame, as shown in Fig. 4.
Crap. 4
If necessary, it is allowed to: draw a connecting line from the second (last) part of the frame (Fig. 5 A); end the connecting line with an arrow and from the material side of the part (Fig. 5 b).
Crap. 5
2.5. If the tolerance relates to a surface or its profile, then the frame is connected to the contour line of the surface or its continuation, and the connecting line should not be a continuation of the dimension line (Fig. 6, 7).
Crap. 6
Crap. 7
2.6. If the tolerance relates to an axis or plane of symmetry, then the connecting line must be a continuation of the dimension line (Fig. 8 A, b). If there is not enough space, the dimension line arrow can be combined with the connecting line arrow (Fig. 8 V).
Crap. 8
If the size of an element has already been indicated once, then it is not indicated on other dimension lines of this element, used to symbolize the tolerance of shape and location. A dimension line without size should be considered as component symbol for tolerance of shape or location (Fig. 9).
Crap. 9
Crap. 10
2.7. If the tolerance relates to the sides of the thread, then the frame is connected to the image in accordance with the drawing. 10 A. If the tolerance relates to the thread axis, then the frame is connected to the image in accordance with the drawing. 10 b. 2.8. If the permit relates to common axis(plane of symmetry) and from the drawing it is clear for which surfaces this axis (plane of symmetry) is common, then the frame is connected to the axis (plane of symmetry) (Fig. 11 A, b).
Crap. eleven
2.9. Before the numerical value of the tolerance should be indicated: symbol Æ, if the circular or cylindrical tolerance field is indicated by diameter (Fig. 12 A); symbol R , if a circular or cylindrical tolerance field is indicated by a radius (Fig. 12 b); symbol T, if the tolerances of symmetry, intersection of axes, the shape of a given profile and a given surface, as well as positional tolerances (for the case when the positional tolerance field is limited to two parallel straight lines or planes) are indicated in diametrical terms (Fig. 12 V); symbol T/2 for the same types of tolerances, if they are indicated in radius terms (Fig. 12 G); the word "sphere" and the symbols Æ or R, if the tolerance field is spherical (Fig. 12 d).
Crap. 12
2.10. The numerical value of the tolerance of the shape and location of surfaces, indicated in the frame (Fig. 13 A), refers to the entire length of the surface. If the tolerance relates to any part of the surface of a given length (or area), then the given length (or area) is indicated next to the tolerance and separated from it by an inclined line (Fig. 13 b, V), which should not touch the frame. If it is necessary to assign a tolerance over the entire length of the surface and at a given length, then the tolerance at a given length is indicated under the tolerance over the entire length (Fig. 13 G).
Crap. 13
(Changed edition, Amendment No. 1). 2.11. If the tolerance must relate to an area located in a certain place of the element, then this area is marked with a dash-dotted line and limited in size according to the lines. 14.
Crap. 14
2.12. If it is necessary to specify a protruding tolerance field of location, then after the numerical value of the tolerance the symbol is indicated. The contour of the protruding part of the normalized element is limited by a thin solid line, and the length and location of the protruding tolerance field by dimensions (Fig. 15).
Crap. 15
2.13. Inscriptions supplementing the data given in the tolerance frame should be placed above the frame below it or as shown in Fig. 16.
Crap. 16
(Changed edition, Amendment No. 1). 2.14. If for one element it is necessary to specify two different types of tolerance, then it is possible to combine frames and arrange them according to the features. 17 (top designation). If for a surface it is required to indicate simultaneously a symbol for the tolerance of a shape or location and its letter designation used to standardize another tolerance, then frames with both symbols can be placed side by side on the connecting line (Fig. 17, lower designation). 2.15. Repeating the same or different types tolerances, denoted by the same sign, having the same numerical values and relating to the same bases, can be indicated once in a frame from which one connecting line extends, which then branches to all standardized elements (Fig. 18).
Crap. 17
Crap. 18
2.16. Tolerances for the shape and location of symmetrically located elements on symmetrical parts are indicated once.
3. DESIGNATION OF BASES
3.1. The bases are indicated by a blackened triangle, which is connected using a connecting line to the frame. When making drawings using computer output devices, it is permissible not to blacken out the triangle indicating the base. The triangle indicating the base should be equilateral, with a height approximately equal to the font size of the dimensional numbers. 3.2. If the base is a surface or its profile, then the base of the triangle is placed on the contour line of the surface (Fig. 19 A) or on its continuation (Fig. 19 b). In this case, the connecting line should not be a continuation of the dimension line.
Crap. 19
3.3. If the base is an axis or plane of symmetry, then the triangle is placed at the end of the dimension line (Fig. 18). If there is not enough space, the arrow of the dimension line can be replaced with a triangle indicating the base (Fig. 20).
Crap. 20
If the base is a common axis (Fig. 21 A) or plane of symmetry (Fig. 21 b) and it is clear from the drawing for which surfaces the axis (plane of symmetry) is common, then the triangle is placed on the axis.
Crap. 21
(Changed edition, Amendment No. 1). 3.4. If the base is an axis center holes, then next to the designation of the base axis the inscription “Axis of centers” is made (Fig. 22). It is allowed to designate the base axis of the center holes in accordance with the drawing. 23.
Crap. 22
Crap. 23
3.5. If the base is a certain part of the element, then it is indicated by a dash-dot line and limited in size in accordance with the line. 24. If the base is a certain location of the element, then it must be determined by dimensions according to the drawings. 25.
Crap. 24
Crap. 25
3.6. If there is no need to select one of the surfaces as a base, then the triangle is replaced with an arrow (Fig. 26 b). 3.7. If connecting the frame to the base or other surface to which the position deviation relates is difficult, the surface is designated by a capital letter inscribed in the third part of the frame. The same letter is inscribed in a frame, which is connected to the designated surface with a line capped with a triangle if the base is designated (Fig. 27 A), or an arrow if the designated surface is not a base (Fig. 27 b). In this case, the letter should be placed parallel to the main inscription.
Crap. 26
Crap. 27
3.8. If the size of an element has already been indicated once, then it is not indicated on other dimension lines of this element used to symbolize the base. A dimension line without a dimension should be considered as an integral part of the base symbol (Fig. 28).
Crap. 28
3.9. If two or more elements form a combined base and their sequence does not matter (for example, they have a common axis or plane of symmetry), then each element is designated independently and all the letters are inscribed in a row in the third part of the frame (Fig. 25, 29). 3.10. If it is necessary to specify a location tolerance relative to a set of bases, then the letter designations of the bases are indicated in independent parts (the third and further) of the frame. In this case, the bases are written in descending order of the number of degrees of freedom they are deprived of (Fig. 30).
Crap. 29
Crap. thirty
4. INDICATING NOMINAL LOCATION
4.1. Linear and angular dimensions that determine the nominal location and (or) nominal shape of elements limited by tolerance, when assigning a positional tolerance, slope tolerance, tolerance of the shape of a given surface or a given profile, are indicated in the drawings without maximum deviations and are enclosed in rectangular frames (Fig. 31 ).
Crap. 31
5. DESIGNATION OF DEPENDENT TOLERANCES
5.1. Dependent tolerances of shape and location indicate conventional sign, which is placed: after the numerical value of the tolerance, if dependent tolerance associated with the actual dimensions of the element in question (Fig. 32 A); after letter designation bases (Fig. 32 b) or without a letter designation in the third part of the frame (Fig. 32 G), if the dependent tolerance is related to the actual dimensions of the base element; after the numerical value of the tolerance and the letter designation of the base (Fig. 32 V) or without a letter designation (Fig. 32 d), if the dependent tolerance is related to the actual dimensions of the considered and base elements. 5.2. If a location or shape tolerance is not specified as dependent, then it is considered independent.
Crap. 32
ANNEX 1
Mandatory
SHAPE AND SIZES OF SIGNS
APPENDIX 2
Information
EXAMPLES OF INDICATIONS ON THE DRAWINGS OF TOLERANCES FOR THE FORM AND LOCATION OF SURFACES
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Type of admission |
Indication of tolerances of shape and location by symbol |
Explanation |
| 1. Straightness tolerance | The straightness tolerance of the cone generatrix is 0.01 mm. | |
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Tolerance for straightness of the hole axis Æ 0.08 mm (tolerance dependent). | |
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The surface straightness tolerance is 0.25 mm over the entire length and 0.1 mm over a length of 100 mm. | |
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Surface straightness tolerance in the transverse direction 0.06 mm, in longitudinal direction 0.1 mm. | |
| 2. Flatness tolerance |
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Surface flatness tolerance 0.1 mm. |
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Surface flatness tolerance 0.1 mm over an area of 100 ´ 100 mm. | |
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The tolerance for flatness of surfaces relative to the common adjacent plane is 0.1 mm. | |
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The flatness tolerance of each surface is 0.01 mm. | |
| 3. Roundness tolerance |
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The shaft roundness tolerance is 0.02 mm. |
| Cone roundness tolerance 0.02 mm. | ||
| 4. Cylindricity tolerance |
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Shaft cylindricity tolerance 0.04 mm. |
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The shaft cylindricity tolerance is 0.01 mm over a length of 50 mm. The shaft roundness tolerance is 0.004 mm. | |
| 5. Longitudinal profile tolerance |
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Shaft roundness tolerance 0.01 mm. The tolerance of the profile of the longitudinal section of the shaft is 0.016 mm. |
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The tolerance of the profile of the longitudinal section of the shaft is 0.1 mm. | |
| 6. Parallelism tolerance |
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Tolerance of parallelism of the surface relative to the surface A 0.02 mm. |
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Tolerance for parallelism of the common adjacent plane of surfaces relative to the surface A 0.1 mm. | |
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Parallelism tolerance of each surface relative to the surface A 0.1 mm. | |
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The tolerance for parallelism of the hole axis relative to the base is 0.05 mm. | |
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The tolerance for parallelism of the hole axes in a common plane is 0.1 mm. The tolerance for skew of the hole axes is 0.2 mm. Base - hole axis A. | |
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Tolerance for parallelism of the hole axis relative to the hole axis A 00.2 mm. | |
| 7. Perpendicularity tolerance |
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Tolerance of surface perpendicularity to surface A 0.02 mm. |
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Tolerance of perpendicularity of the hole axis relative to the hole axis A 0.06 mm. | |
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Tolerance for perpendicularity of the protrusion axis relative to the surface A Æ 0.02 mm. | |
| The perpendicularity tolerance of the protrusion relative to the base is 0.1 mm. | ||
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The tolerance for perpendicularity of the protrusion axis in the transverse direction is 0.2 mm, in the longitudinal direction 0.1 mm. Base - base | |
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Tolerance for perpendicularity of the hole axis relative to the surface Æ 0.1 mm (dependent tolerance). | |
| 8. Tilt tolerance |
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Tolerance for surface inclination relative to surface A 0.08 mm. |
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Tolerance for inclination of the hole axis relative to the surface A 0.08 mm. | |
| 9. Alignment tolerance |
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Tolerance for hole alignment relative to hole Æ 0.08 mm. |
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The tolerance for coaxiality of two holes relative to their common axis is Æ 0.01 mm (dependent tolerance). | |
| 10. Symmetry tolerance |
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Groove symmetry tolerance T 0.05 mm. Base - plane of symmetry of surfaces A |
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Hole symmetry tolerance T 0.05 mm (tolerance dependent). The base is the plane of symmetry of surface A. | |
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Tolerance for the symmetry of the osp hole relative to the general plane of symmetry of the grooves AB T 0.2 mm and relative to the general plane of symmetry of the grooves VG T 0.1 mm. | |
| 11. Positional tolerance |
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Positional tolerance of the hole axis Æ 9.06 mm. |
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Positional tolerance of hole axes Æ 0.2 mm (tolerance dependent). | |
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Positional tolerance of the axes of 4 holes Æ 0.1 mm (dependent tolerance). Base - hole axis A(tolerance dependent). | |
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Positional tolerance of 4 holes Æ 0.1 mm (tolerance dependent). | |
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Positional tolerance of 3 threaded holes Æ 0.1 mm (tolerance dependent) in an area located outside the part and protruding 30 mm from the surface. | |
| 12. Axis intersection tolerance |
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Hole axis intersection tolerance T 0.06 mm |
| 13. Radial runout tolerance |
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The tolerance for radial runout of the shaft relative to the cone axis is 0.01 mm. |
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Tolerance for radial runout of the surface relative to the common axis of the surface A And B 0.1 mm | |
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Tolerance for radial runout of a surface area relative to the hole axis A 0.2 mm | |
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Hole radial runout tolerance 0.01 mm First base - surface L. The second base is the axis of surface B. The tolerance for axial runout relative to the same bases is 0.016 mm. | |
| 14. Axial runout tolerance |
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Tolerance of axial runout on a diameter of 20 mm relative to the surface axis A 0.1 mm |
| 15. Runout tolerance in a given direction |
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Cone runout tolerance relative to the hole axis A in a direction perpendicular to the generatrix of the 0.01 mm cone. |
| 16. Total radial runout tolerance |
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Tolerance for total radial runout relative to the common axis of the surface A And B 0.1 mm. |
| 17. Tolerance for complete axial runout |
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The tolerance for complete end runout of the surface relative to the surface axis is 0.1 mm. |
| 18. Tolerance of the shape of a given profile |
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Shape tolerance of a given profile T 0.04 mm. |
| 19. Shape tolerance of a given surface |
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Tolerance of the shape of a given surface relative to the surfaces A, B, C, T 0.1 mm. |
| 20. Total tolerance of parallelism and flatness |
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The total tolerance for parallelism and flatness of the surface relative to the base is 0.1 mm. |
| 21. Total tolerance of perpendicularity and flatness |
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The total tolerance for perpendicularity and flatness of the surface relative to the base is 0.02 mm. |
| 22. Total tolerance for slope and flatness |
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Total tolerance for inclination and flatness of the surface relative to the base 0.05 mi |
In previously issued documentation, tolerances for coaxiality, symmetry, and displacement of axes from the nominal location (positional tolerance), indicated respectively by signs 
or text in the technical requirements, should be understood as tolerances in radius terms. 2. Indication of the tolerances of the shape and location of surfaces in text documents or in the technical requirements of the drawing should be given by analogy with the text of the explanation for symbols tolerances of shape and location given in this appendix. In this case, the surfaces to which tolerances of shape and location apply or which are taken as the base should be designated by letters or given their design names. It is allowed to indicate a sign instead of the words “tolerance dependent” and instead of instructions before the numerical value of the symbols Æ ; R; T; T/2 entry in text, for example, “axis positional tolerance 0.1 mm in diametrical terms” or “symmetry tolerance 0.12 mm in radial terms.” 3. In the newly developed documentation, the entry in the technical requirements on the tolerances for ovality, cone-shape, barrel-shape and saddle-shape should, for example, be as follows: “Tolerance for surface ovality A 0.2 mm (half difference in diameters). In technical documentation developed before 01/01/80, limit values ovality, conicality, barrel-shapedness and saddle-shapedness are determined as the difference between the largest and smallest diameters. (Changed edition, Amendment No. 1).
A hole is an open or through opening in a solid object.
The hole drawing is carried out on the basis of GOST 2.109-73 - a unified system of design documentation (ESKD).
You can download this simple drawing for free to use for any purpose. For example, for placement on a nameplate or sticker.
How to draw a drawing:
You can draw a drawing either on a sheet of paper or using specialized programs. No special engineering knowledge is required to complete simple sketch drawings.
A sketch drawing is a drawing made “by hand”, observing the approximate proportions of the depicted object and containing sufficient data for the manufacture of the product.
The design drawing with all the technological data for manufacturing can only be completed by a qualified engineer.
To designate in the drawing, you must perform the following operations:
1. Draw an image;
2. Add dimensions (see example);
3. Specify for production (read more about technical requirements below in the article).
It is most convenient to draw on a computer. Subsequently, the drawing can be printed on paper using a printer or plotter. There are many specialized programs for drawing on a computer. Both paid and free.
Drawing example:
This image shows how simple and quickly drawing can be done using computer programs.
List of programs for drawing on a computer:
1. KOMPAS-3D;
2. AutoCAD;
3. NanoCAD;
4. FreeCAD;
5. QCAD.
Having studied the principles of drawing in one of the programs, it is not difficult to switch to working in another program. Drawing methods in any program are not fundamentally different from each other. We can say that they are identical and differ from each other only in convenience and the presence of additional functions.
Technical requirements:
For the drawing it is necessary to indicate dimensions sufficient for manufacturing, maximum deviations and roughness.
The technical requirements for the drawing should indicate:
1) Manufacturing and control method, if they are the only ones that guarantee the required quality of the product;
2) Specify a specific technological method, guaranteeing that certain technical requirements for the product are met.
A little theory:
A drawing is a projection image of a product or its element, one of the types of design documents containing data for the production and operation of the product.
A drawing is not a drawing. The drawing is made according to the dimensions and scale of the real product (structure) or part of the product. Therefore, to carry out drawing work, the work of an engineer with sufficient experience in producing drawing work is necessary (however, to beautifully display a product for booklets, it is quite possible that you will need the services of an artist who has an artistic view of the product or part of it).
A drawing is a constructive image with necessary and sufficient information about dimensions, manufacturing method and operation. You can download the drawing presented on this page for free.
A drawing is an artistic image on a plane created by means of graphics (brush, pencil or specialized program).
A drawing can be either an independent document or part of a product (structure) and technical requirements related to surfaces processed together. Instructions for joint processing are placed on all drawings involved in the joint processing of products.
For more information on drawings, technical requirements for design and indication of manufacturing methods, see GOST 2.109-73. See the list of standards for the development of design documentation.
Information for ordering drawings:
In our design organization, you can design any product (both parts and assemblies), which will include a hole drawing as an element of the design documentation of the product as a whole. Our design engineers will develop documentation in the shortest possible time in strict accordance with your technical specifications.
