Scale- the ratio of the linear dimensions of the object depicted in the drawing to its dimensions in kind. A scale can be expressed numerically (numerical scale) or represented graphically (linear scale).
Numerical scale denoted by a fraction, which shows the factor of increase or decrease in the size of the image in the drawing. When making drawings, depending on their purpose, the complexity of the shapes of objects and structures, their sizes, the following numerical scales are used ( GOST 2.302-68) *:
decrease: 1:2; 1: 2,5; 1:4; 1:5; 1: 10; 1: 15; 1: 20; 1: 25; 1: 40; 1: 50; 1: 75; 1: 100; 1: 200; 1: 400; 1: 500; 1: 800; 1: 1000;
magnification: 2:1; 2.5:1; 4:1; 5:1; 10:I; 20:1; 40:1; 50:1; 100:1;
natural size
1:1.
When designing master plans for large objects, a scale of 1: 2000 is used; 1: 5000; 1: 10,000; 1: 20,000; 1: 25,000; 1:50,000.
If the drawing is made on the same scale, its value is indicated in the designated column of the main inscription of the drawings according to the 1:1 type; 1:2; 1: 100, etc. If any image in the drawing is made in a scale different from that indicated in the main inscription, then under the corresponding name of the image indicate a scale of type M 1: 1; M 1:2, etc.
When using a numerical scale when making drawings, you have to make calculations to determine the size of the line segments drawn on the drawing. For example, to determine the length of a segment in a drawing with a length of the depicted object of 4000 mm and a numerical scale of 1:50, you need to divide 4000 mm by 50 (the degree of reduction) and put the resulting value (80 mm) on the drawing.
To reduce calculations, use a scale bar or construct a corresponding numerical linear scale, as shown in the figure for a numerical scale of 1:50.
Draw a straight line and mark the base of the scale on it several times - the value that is obtained by dividing the accepted unit of measurement (1 m = 1000 mm) by the reduction size of 1000: 50 = 20 mm. The first segment on the left side is divided into several equal parts so that each division corresponds to a whole number. If this segment is divided into 10 parts, then each division will correspond to 0.1 m; if into 5 parts - then 0.2 m. Above the points of dividing the line into segments, equal to the base scale, inscribe numerical values that correspond to natural sizes, while the first division on the right always has a zero. The value of small divisions from zero to the left is also inscribed, as shown in the figure.
In order to take, for example, a size of 4.65 m (4650 mm), using the constructed linear scale, you need to place one leg of the measuring compass at 4 m, and the other at the sixth and a half fractional division to the left of zero. If the accuracy is insufficient, a transverse scale is used.
Transverse scale makes it possible to express or determine the size with an error of up to hundredths of the basic unit of measurement. So, the figure below shows the definition of a size equal to 4.65 m.
Tenths are taken on a horizontal scale segment, and hundredths on a vertical scale.
In cases where it is necessary to construct an enlarged or reduced image, made according to a given drawing, the scale of which can be arbitrary, use angular (proportional) scale.
The angular scale is constructed in the form of a right triangle, the ratio of the legs of which is equal to the multiplicity of the change in image scale (h:H). Using the angular scale, you can change the scale of the image using abstract values and without calculating the size of the depicted object.
For example, you need to depict a given drawing on an enlarged scale. For this we are building right triangle ABC, in which the vertical leg BC is equal to a segment of any straight line taken in a given drawing, and the horizontal leg AB is equal to the length of the corresponding segment on the scale of the enlarged drawing. Thus, in order to increase any segment of a straight line of a given drawing, for example h, it is necessary to lay it parallel to the leg BC of the angular scale (vertically) between the leg A B and the hypotenuse AC. Then the increased size of the segment will be equal to the dimension H taken (horizontally) on the AB side of the angular scale.
Another method can also be used. As in the first case, let us plot some segment of the given drawing h vertically. Then, in the same place, we plot the length of the segment h1 with the corresponding increase and draw an inclined straight line AD through the resulting point. We obtain the required segments the same way. It is convenient to use the meter by drawing angular scale on graph paper.
The angular scale can also be used to convert quantities from one numerical scale to another.
In an enlarged drawing, as in a given one, it is necessary to indicate in numbers the actual dimensions that the depicted object has in real life, and not in the drawing.
Scale
scale of reduction:
scale of increase:
The main lines of the drawing, features of their outline in accordance with GOST.
In order for the drawing to be expressive and easy to read, it must be decorated with lines of varying thickness and style. The lines and their purposes are established by GOST 2.303-68*.
The main line of the drawing is the visible contour line. The thickness of the solid main line s should be in the range from 0.5 to 1.4 mm, depending on the size and complexity of the image, as well as on the format and purpose of the drawing.
Drawing lines.
| Name | Line thickness | Main purpose | |
| Solid main | s (0.5 to 1.4) | Visible contour line; visible transition lines; contour lines of the section (extracted and included in the section). | |
| Solid thin | From s/3 to s/2 (from 0.2-0.5 to 0.3-0.75) | Contour lines of the superimposed section; dimensional and extension lines; hatch lines; leader lines; leader line shelves and label underlining; lines to depict boundary details; limit lines of extension elements in views, sections and sections; transition lines depicted; fold lines on developments; projection axis, traces of planes, lines of construction of characteristic points for special constructions. | |
| Solid wavy | Break lines; demarcation lines between view and section | ||
| Line | Invisible contour lines; transition lines are invisible. | ||
| Line-dotted thin | Axial and center lines; section lines, which are axes of symmetry for superimposed or extended sections; lines for depicting parts of products in extreme or intermediate positions; lines for the scan image combined with the view. | ||
| Dash-dotted thickened | From s/2 to 2/3s (from 0.3-0.75 to 0.4-1) | Lines indicating surfaces to be heat treated or coated; lines for depicting elements located in front of the cutting plane. | |
| Open | From s to 1.5s (from 0.6-1.5 to 0.9-2.25) | Section lines | |
| Solid thin with kinks | From s/3 to s/2 (from 0.2-0.5 to 0.3-0.75) | Long break lines | |
| Dot-dash with two dots thin | From s/3 to s/2 | Fold lines on developments; lines for depicting parts of products in extreme or intermediate positions and for depicting a scan combined with the view |
Dashed-dotted lines should end with dashes, not dots. The center of the circle should be marked by the intersection of the strokes. In circles with a diameter of less than 12 mm, dash-dotted lines used as center lines should be replaced with solid thin lines. Dimensional numbers and inscriptions should not intersect with drawing lines.
For the frames of drawings, tables, main inscriptions and specifications, solid lines of thickness s should be used.
Drawing fonts
On drawings and other technical documents, in addition to dimensional numbers, various inscriptions are applied both in the columns of the main inscription and in the field of the drawing - inscriptions indicating images, as well as those relating to individual elements of the depicted product or building. Labels must be clear and legible.
GOST 2.304-81* establishes drawing fonts for handwritten inscriptions on drawings and technical documents of all industries and construction.
The inclination of the letters and numbers of this font to the base of the line is approximately 75 degrees.
Main inscriptions, headings, names may be written in straight letters. Inscriptions can be made only from capital letters or in a combination of uppercase and lowercase letters.
The font size is determined by the height h of the capital letters (in millimeters).
Installed following sizes font: 2.5; 3.5; 5; 7; 10; 14; 20; 28; 40.
When writing numbers and letters, keep the following in mind:
For all text, the thickness of the stroke lines should be the same;
the lower branches of the letter D and the upper sign of the letter Y should be made due to the spaces between the lines, and the lower and lateral processes of the letters C and Ш - due to the spaces between the lines and letters;
a capital letter in a word with lowercase letters must have the same line thickness as the lowercase letters;
the height of lowercase letters is 7/10 of the height of uppercase letters;
the width of most capital letters is 6/10 h
the width of the letters A, D, M, X, Y, Yu is 7/10h, and the letters ZH, F, Ш, Б – 8/10h
The width of lowercase letters and Arabic numerals, except for the number 1, is 5/10h
The number 1 should be placed at a normal distance from adjacent numbers and letters.
the distance between lines must be at least the height of lowercase letters
with an apparent increase in the spaces between adjacent letters, for example G and A, G and a, R and D, T and L, etc., these spaces should be reduced.
Selecting the main type of part.
The drawing begins with the selection of the main image.
The main requirement for the main image is that it must convey the most complete idea of the shape and dimensions of the part.
As the main image (front view), either a frontal section or a combination of the view and the section can be used.
Flat parts from sheet material depicted in one projection showing their outline images, the thickness of the part is indicated by a conventional notation.
To produce shaped parts from sheet material, precise developments or approximate blanks for pressed parts with drawing are required - these are flat parts made from sheet material.
The number of images (types, sections, sections) of an object in the drawing should be the smallest, but sufficient to identify its external and internal shape and should make it possible to rationally apply dimensions.
In some cases, one projection with the corresponding symbol placed next to the dimensional number gives a complete picture of the shape of the depicted object. So, for example, the diameter sign indicates that the depicted object is a body of revolution; the square sign means that the depicted object has the shape of a prism with a normal cross section in the form of a square; the word “sphere” written before the diameter icon indicates that the surface is spherical; the symbol "S" (thickness) in front of the dimension number replaces the second projection of the part, which has the shape of a parallelepiped, etc.
After analyzing the shape of the part, it is possible to determine which images are necessary to fully convey the external and internal forms this detail. For most parts of machines and mechanisms, it is enough to make 3 images, taking into account that to depict the invisible contours of the product you can use dashed lines, you can combine parts of the views with parts of the corresponding sections, use complex sections, etc.
Selecting the main image (especially for a part drawing) is the most important stage in working on the drawing. If you make a mistake at this stage, nothing else will compensate for it. The drawing will be understood correctly by an experienced person, but reading will take a lot of time. A less experienced person will not only waste even more time, but may also misunderstand the contents of the drawing, resulting in a manufacturing defect.
Let's consider the procedure for selecting the main image, conditionally dividing it into three stages.
1.Determination of the viewing direction (projection direction) to form the main image.
2.Determining the content of the main image.
3.Selecting the position of the main image.
In assembly drawings, the main image should show the relative position of the main parts of the product, usually hidden from the view of the observer. Therefore, this image is a section, like most other images placed on the drawing.
Complex cuts.
A cut made by several cutting planes is called complex.
If a complex cut is obtained using parallel planes, then it is called stepped; if the cutting planes intersect, then it is called broken.
The position of the cutting plane is indicated in the drawing by a section line. An open line should be used for the section line. For a complex cut, strokes are also made at the bends of the section line.
For broken cuts, the secant planes are conventionally rotated until they are aligned into one plane, and the direction of rotation may not coincide with the direction of view. If the combined planes turn out to be parallel to one of the main projection planes, then the broken section can be placed in the place of the corresponding type. When rotating the secant plane, the elements of the object located behind it should be drawn as they are projected onto the corresponding plane to which the alignment occurs.
(Sections can be placed anywhere in the drawing, as well as rotated to a position corresponding to that accepted for of this subject in the main image. In the latter case, the word “Rotated” must be added to the inscription.
It is also allowed to separate the section and view by a thin dash-dotted line, coinciding with the trace of the plane of symmetry not of the entire object, but only of its part if it is a body of rotation.)
Thin walls such as stiffeners, as well as flywheel spokes, are shown unshaded if the cutting plane is directed along the axis or long side of this element.
Also, parts such as bolts, screws, rivets, etc., are shown uncut in a longitudinal section. If such parts have a hole or other plane, it is necessary to make a local cut.
Local cut
If you want to identify the shape of an element on small area parts, you don't have to cut the entire part. In this case, only part of the corresponding section is shown. An incision that serves to clarify the structure of an object only in a separate limited place is called local. The local section is highlighted in the view by a solid wavy line, which should not coincide with any other lines in the image.
Section.
Section
(Sections that are not part of the section are divided into extended and superimposed. The extended section is depicted in a free space of the drawing, if possible close to the view to which it belongs. It is allowed to depict this section in a gap between parts of the same view.
The axis of symmetry of an extended or superimposed section is indicated by a thin dash-dotted line without letters or arrows. It is allowed to place the section anywhere in the drawing field, as well as with a rotation. In the latter case, the word “Rotated” must be added to the inscription.
GOST 2.306-68* provides a special type of shading for various materials, from which the parts are made.)
15.Varieties of sections, their design in the drawing.
Section is the image of a flat figure resulting from the mental dissection of an object by a plane or several planes.
The section shows only what is obtained directly in the cutting plane.
In accordance with GOST 2.303-68, an open thickened line is used for the section line with arrows indicating the direction of view and designating it in the same capital letters of the Russian alphabet, and the section itself is accompanied by an inscription according to type A-A. In construction drawings, it is allowed to use numbers instead of letters at the section line, as well as inscribe the name of the section. The length of the arrow is selected within 10-25 mm. The arrows are applied at a distance of 2-3 mm from the end of the thickened stroke. The starting and ending thick strokes should not intersect the outline of the image. For complex sections, it is allowed to connect the ends of an open line with a thin dash-dotted line. In construction drawings, for symmetrical sections, an open line is used with its designation, but without arrows.
Sections that are not part of the section are divided into extended and superimposed. The extended section is depicted in a free space of the drawing, if possible close to the view to which it belongs. It is allowed to depict this section in a gap between parts of the same type.
The superimposed section is placed directly on the object view.
Extended sections should be given preference over superimposed ones. The contour of the extended section should be depicted with solid main lines, and the contour of the superimposed section with solid thin lines, and the lines of the image of the object at the location of the superimposed section are not interrupted.
The axis of symmetry of an extended or superimposed section is indicated by a thin dash-dotted line without letters or arrows. It is allowed to place the section anywhere in the drawing field, as well as with a rotation. In the latter case, the word “Rotated” must be added to the inscription. For asymmetrical sections located in a gap or superimposed, the section line is drawn with arrows, but not marked with letters.
In views and sections, it is allowed to depict in a simplified manner the projections of the lines of intersection of surfaces, if their precise construction is not required.
GOST 2.306-68 provides for a special type of shading for various materials from which parts are made.
The difference between a section and a section.
If an object is conditionally cut by a plane, mentally discard the cut-off part of it located in front of the secant plane, and project the remaining part from the side of the secant plane onto the projection plane, then such a projection is called a cut.
Consequently, a cut is an image of an object mentally dissected by one or more planes, while the mental dissection of an object relates only to this cut and does not entail a change in other images of the same object. The section shows what lies in the cutting plane (section) and what is located behind it.
A section is an image of a flat figure resulting from the mental dissection of an object by a plane or several planes.
The section shows only what is obtained directly in the cutting plane.
A section differs from a section in that it shows not only what is in the cutting plane, but also what is located behind it.
Using scales when depicting drawings.
Scale is a ratio that shows how many times the value of a line segment in a drawing is less or greater than the value of the corresponding line segment in kind.
Scales can be numerical or graphic. The latter are divided into linear, transverse and angular.
When drawing drawings using a numerical scale, you have to make arithmetic calculations to determine the size of the line segments drawn on the drawing.
To reduce calculations and quickly obtain the size of line segments drawn on a drawing at a certain scale, use a scale bar or construct a linear scale corresponding to the numerical scale.
The transverse scale makes it possible to express or determine the size with an error of up to hundredths of the basic unit of measurement.
In cases where it is necessary to construct an enlarged or reduced image, made according to a given drawing, the scale of which can be arbitrary, an angular scale is used.
The choice of drawing scale depends on the purpose of the drawing. And also on the complexity of the shapes of the object and structure, their sizes.
According to GOST 2.302-68, the following scales are used when making drawings:
scale of reduction:
1:2; 1:2.5; 1:4; 1:5; 1:10; 1:15; 1:20; 1:25; 1:40; 1:50; 1:75; 1:100; 1:200; 1;400; 1:500; 1:800; 1:1000; for life-size images M 1:1;
scale of increase:
2:1; 2.5:1; 4:1; 5:1; 10:1; 20:1; 40:1; 50:1; 100:1.
When designing master plans for large objects, it is recommended to use a scale of 1:2000; 1:5000; 1:10000; 1:20000; 1:25000; 1:50000.
The scale indicated in the designated column of the title block of the drawing is designated as 1:1; 1:2, etc., and in other cases - according to type M 1:1; M 1:2, etc.
This article covers the main questions about how to How to make a drawing, scale of drawings, design of drawings, etc.
The problem of drawing up a drawing on their own often arises among entry-level students studying in technological fields or receiving education in the field of artistic design or technical design. The rules that must be followed when creating drawing works are recorded in Gosstandart. Anyone who receives education in these areas should know and adhere to them. However, the Gosstandart rules were issued for industrial use, so small deviations from the established standards are sometimes allowed in the drawings.
Paper sheet formats and frames for them
Any drawing is drawn up on a sheet of paper of a standardized size, limited by a frame. Such a frame is applied by drawing a line of medium thickness along the markings marked on the sheet.
For drawings of different formats, certain dimensions of the frames outlined in them are established:
- A0 format contains a frame measuring 1189 x 841 mm
- A1 format – 594 x 841 mm
- A2 format – 594 x 420 mm
- A3 format – 297 x 420 mm
- A4 format – 297 x 210 mm
Each smaller drawing is obtained by halving the values of the previous format.
Title block of the drawing
The inscription on the drawing is located in the corner located on the right. It states:
- Title of the drawing work
- The material from which this part is made
- The company that manufactures the part
When using A4 format, the main inscription is placed on the smallest side. If the format used is larger than A4, then the inscription can be placed on either side.
Initial data for the drawing and working with it
To do simple drawing, you can either depict the detail that the drawing will depict in the future, on paper, in the form of a drawing in three projections, or have it before your eyes in the original.
When depicting a part in the form of a three-dimensional drawing, it is useful to:
- First, practice on simple objects - a notebook, a book, a plate - with your eyes closed, try to imagine their volume and outline
- Try to display on a piece of paper what you presented and compare the result with the original
- Make corrections to parts of the resulting drawing that do not correspond to its original - it is possible that the proportions or its dimensions are not observed
- Try to “decompose” a drawing depicted in space into its component projections along the coordinate axes imagined
- Draw on the drawing all the dimensions required for someone else to make the item.
If the successive steps of the above algorithm were performed correctly, then the copy of the original depicted on paper will correspond to it. If their similarity was not obtained, adjustments will need to be made to the dimensional chains.
A dimensional chain is the total size of a certain part of an image of an object applied to paper, which cannot be distorted up or down. Of course, depending on what goal you are pursuing when depicting an object in a drawing, the accuracy of the dimensions may vary. For example, for domestic purposes, it sometimes deviates within one to one and a half millimeters, and this is often acceptable. In technical drawing, dimensional chains are established taking into account various factors.
What is needed to “measure” a drawing?
The correct creation of a drawing consists not only in observing the external similarity of the image applied to whatman paper or recreated in a computer program with a real object. For technical purposes, it is necessary that all dimensions of the image match the original. In this regard, the concept of accuracy tolerance was introduced.
Dimensional tolerances indicated in technical drawings are indicated taking into account the articulation of two adjacent parts with each other. A whole system of tolerances has been developed, taking into account how parts interact with each other (moving or stationary interaction), as well as the nature of probable movements during their assembly or disassembly (often, rarely, always, never) and so on.
How to learn to read drawings?
Drawings are 2-dimensional architectural schematic sketches that show the size of a building's design. For materials that will be used in construction. Learning to read blueprints is important for builders and anyone who hires architects to draw them.
Spatial imagination training
Standard drawings usually have three projections of an object in which the coordinate points X, Y, Z are located on the axis. However, with their composition, the scaling remains and the same is set for all.
It is human nature to observe each object or detail in geometric isometry from a certain angle of view. This often happens in the branches of mechanical engineering drawing, and in the design development of objects of artistic and technical design. Therefore, it is worth presenting the drawing object as flat in a certain projection.
And an additional detail is the projection connection of different images of the drawing object. If all the elements of both configurations are built incorrectly with scale distortions, which will lead to a discrepancy between the copy of the drawing and the originals. Therefore, it is worth following a number of rules in the process of drawing up a projection:
Measurements are carried out using a ruler - for simple ones, with a caliper or micrometer - for complex parts, for all dimensional elements. Establish their relative position for each of the projections of the part. Compare the results obtained with real picture details. With bug fixes. Final distance measurements are taken on the original object or its mock-up drawing. If all the data is correct and matches, then the diagrams and drawings were read correctly.
How to apply dimensions correctly?
It doesn’t matter what scale the drawings are made, all attention is paid to the base of the part and its dimensions. When writing a certain number, the unit of measurement, which is standard, is not shown. To indicate the parameters of the part, a dimensional path is drawn with a number located on it. It is drawn parallel to the part segment and is limited by arrows. The minimum distance between the dimension line and the contour of the part is 10 mm.
How can I get help acquiring independent technical graphics skills? To master the skills of reading drawing tables, it is necessary to conduct a training course and practical work. Carry out simple repairs household appliances, for the production of new and old element details. In this case, it is also necessary to make primitive drawings.
Learn how to read drawings correctly, and then learn how to represent a flat picture on a drawing in 3D form. The skills of reading drawings help to competently make all kinds of objects, assemble them from nodes, final product, get the entire device, models and much more.
Types of formats
The format of the sheet with the drawing is determined by the length of the line drawn on the edge of the sheet. The internal ones are made with distances of 2 cm from the left side and 5 mm from the others. It is worth adhering to the exact calculations of the drawing so that when reading them there is no disagreement about what the part looks like.
Drawing frame formats are divided into main and additional directions. The first type included all the resulting schemes by halving the lines from point A0. The dimensions for drawing A1 are carried out so that when the largest axis is divided into two, a rectangle similar to the original sample is obtained. The designation of standard formats consists of a letter and a number from one to five.
Automatic drawing creation
The first place was taken by those drawings that were made using programs computer-aided design. For different designs and details. This applies to two systems - Auto-cad and Compass. They involve reading drawings of a different type. And the image of the entire node is set. And then the parts included in the assembly unit are designed. Thanks to their work with entire libraries of source data. After all, they include profile normalized and standardized elements. Using it in work, the developer is able to insert a fragment into a workpiece, controlling individual parameters, and adapt the drawing to new source data.
Drawing scales
Necessary requirements and features. Let's start with the fact that scale is the ratio of the linear dimensions of the image depicted on a drawing or map to its actual size on the ground or object. Its use greatly facilitates the preparation of maps and drawings, because it is not always convenient and possible to depict an object in its natural size. There are details with large sizes, which do not allow them to be drawn on paper, and it happens that the detail is very small and in order to display it on paper with all the nuances, you have to significantly increase its size. In the presented cases, zoom out and zoom in are used.
Standard scales
Several common reduction scales:
- 1:2,5
For example, the scaling option is 1:4. Number, coming first- one, denotes the actual dimensional characteristics of the object, while the second number, in this case, four, denotes how many times these actual dimensions have been reduced. When depicting a very small object, an increase in scale is used, and this is indicated as follows: 2: 1; 2.5:1; 50:1. With this option, in order to find out the actual dimensions of the object, it is necessary to divide the dimensions indicated in the drawing by the first number reflected in the scale.
How to determine the scale?
In order to depict an object or detail on a sheet of paper, first you need to find out its true dimensions. This can be done by taking measurements of the object depicted in the drawing using a ruler, and only then figuring out how much its actual dimensions should be reduced or increased when drawing its image on a sheet of paper. Drawings are mostly used in construction and in the development of parts and structures. The use of scaling allows designers and constructors to depict on a sheet of paper both a huge building and a smaller exact copy of an airplane.
How to choose the right and, most importantly, the correct scale when working with drawings? Most inexperienced people, when faced with such a question, tend to make quite a lot of mistakes. However, this can be avoided through experience gained over time, or you can seek help from a teacher.
Why is it necessary to follow the rules?
When drawing up drawings and diagrams, it is necessary to follow certain standards reflected in GOST - a document that contains generally accepted rules for applying images, inscriptions, tables and technical requirements. With the help of these rules, any specialist who knows how to read drawings can read a correctly completed drawing. This greatly facilitates communication, during construction and production of parts, between designers and workers carrying out the task according to the drawing. In addition to the scale, other information relating to the subject is also included on the drawing. You should know the basic rules for drawing up drawings and diagrams:
- If graphic information is inappropriate, add additional text
- Any inscription on the drawing is written in abbreviation
- Additional inscriptions are applied parallel to the main one
- Words that cannot be abbreviated are not included in the drawing work.
- Any inscription should not clutter the image and, moreover, interfere with reading the diagram
- When we want to make a leader from the surface of a part, the leader line must end with an arrow. And in the case when the outline of a part is indicated, a dot is placed at the end of the line
- A large amount of information on the diagram must be placed in a frame
- Tables in the drawing are placed next to the image of the part itself, in a space free from the drawing
- If we denote the elements of a part with letters, then we use them strictly in alphabetical order no gaps
If you use all the rules presented above, you can create a truly high-quality drawing work that any specialist will be able to read.
Design of drawings
The process of preparing any work required for certification in construction, design and architectural specialties studied at higher educational institutions, involves the production of drawings. Making a drawing is quite difficult simple task. Its creation must be carried out taking into account certain rules. In addition, any drawing work must be prepared on sheets of a certain size.
The nuances of using different formats
The drawing format is limited by the scope of the work, which is drawn on the sheet with a line of minimum thickness.
The completed work allows students to take into account the dimensions of all formats used in the work. By dividing the work into two parts, a drawing is drawn up containing the following characteristics:
- Dimensions of the sides of the drawing – 841 x 1189 millimeters
- The total sheet area is one square meter
- Format of completed work A0
For other drawing formats, the rules also set the parameters for the dimensions of their sides:
- For A4 format – 210 x 297 millimeters
- For A3 format – 297 x 470 millimeters
- For A2 format – 420 x 594 millimeters
- For A1 format – 594 x 841 millimeters
Also, according to GOST, the possibility of using other formats used as a supplement to the drawings produced by students, which are formed as a result of working on changing the basic parameters upward, should be taken into account. At the same time, to create them, a value that is a multiple of the sizes used in the basic formats is used, and the coefficient of the changes made must necessarily be an integer.
When choosing a scale for drawings, we use the following GOST standards:
GOST 2.302-68 one system design documentation. Scale.
GOST 21.501-2011 System of design documentation for construction. Rules for the execution of working documentation of architectural and structural solutions.
GOST R 21.1101-2013 System of design documentation for construction. Basic requirements for design and working documentation
When developing drawings, the dimensions of graphic images of structures, components, and diagrams, as a rule, do not correspond actual sizes. Size ratio graphic image there is a certain ratio to the size of the depicted object, which is usually called scale. To be precise:
Scale is the ratio of the linear dimensions of the image of an object in the drawing to its actual dimensions.
In accordance with GOST R21.1101-2013, construction drawings, as a rule, do not have scales
put down.
In cases where the images on the sheet are made in different scales, the corresponding scale is indicated above each of them.
Architectural and construction drawings of residential and public buildings carried out on the following scales:
floor plans, sections, facades – 1:50; 1:100; 1:200
fragments of plans, sections, facades – 1:50; 1:100
knots – 1:5; 1:10; 1:20
master plan – 1:500; 1:1000
In some cases it is necessary to choose other scales. Let's consider common list existing scales.
GOST 2.302 establishes the scale of images for drawings.
Scales can be of the following types:
| Natural | Magnification scale | Reduction scale |
| 1:1 | 1: 2 | 2:1 |
| 1:2,5 | 2,5:1 | |
| 1:4 | 4:1 | |
| 1:5 | 5:1 | |
| 1:10 | 10:1 | |
| 1:15 | 20:1 | |
| 1:20 | 40:1 | |
| 1:25 | 50:1 | |
| 1:40 | 100:1 | |
| 1:50 | ||
| 1:75 | ||
| 1:100 | ||
| 1:200 | ||
| 1:400 | ||
| 1:500 | ||
| 1:800 | ||
| 1:1000 |
When developing drawings, the image scale should be taken as minimal as possible, depending on the complexity of the drawing, but ensuring the clarity of copies made from them.
Rice. 26. Part drawing without dimensions
Obviously, this cannot be done, since there are no dimensions.
Drawing dimensions on drawings is a very important operation that significantly affects the ease of reading the drawing.
Rules for applying dimensions are established by standards ESKD (GOST 2.307-68).
When applying dimensions, the following symbols are used: S (thickness), ø (diameter), R (radius), (square).
Sizes available linear and angular. Linear dimensions indicate the length, width, height, thickness, diameter or radius of the part being measured. Angular dimension denotes the size of the angle.
Linear dimensions in the drawings are indicated in millimeters, but the unit of measurement is not indicated.
Angular dimensions indicated in degrees, minutes and seconds with the designation of the unit of measurement.
The number of dimensions in the drawing should be minimal, but sufficient for the manufacture and control of the product.
To apply dimensions use remote And dimension lines, which are drawn with a continuous thin line.
Leader lines- lines that indicate size.
Dimensional lines– the lines on which the size is placed ends with arrows at both ends. The arrows must touch the extension lines; the shape of the arrow is shown in Fig. 27.
Rice. 27. Arrow shape
The dimension line is always drawn parallel to the contour line of the part of the part whose size it defines and perpendicular to the extension lines. If the size is less than 12 mm, then the arrows are placed outside, and if more than 12 mm, then inside (Fig. 28). The dimension line is 10 mm away from the contour of the part drawing, the distance between parallel dimension lines must be at least 7-10 mm.
Extension lines extend beyond the ends of the arrows of the dimension line by 1-5 mm. The size is placed above the size line, closer to its middle.
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Rice. 28. Examples of sizing
With a vertical dimension line, the dimension number is written to the left of it.
The same size is placed in the drawing only once.
First, the smaller size is taken out, and then the larger one. In the drawing, dimension lines should not intersect.
When specifying the size of an angle, the dimension line is drawn in the form of a circular arc with the center at the vertex of the angle.
Diameter sign is placed in front of the dimension number if the circle is drawn completely. The dimension line is drawn through the center of the circle. If the part has several identical holes, then the size is set once, indicating the number of holes (see Fig. 28).
Radius sign is placed when part of a circle is drawn, the dimension line is drawn from the center of the arc.
You should remember the basic concepts:
1) element sizes – dimensions of cutouts, protrusions, holes, grooves;
2) coordinating sizes – dimensions showing the location of the elements relative to the contour of the part and each other;
3) dimensions - the largest dimensions of the part in length, height, width.
In drawing practice, you have to draw images of very large parts (machine tools, ships, cars) and very small ones (clock mechanisms, precision instruments).
Is it possible to depict them in life size? Of course, it’s impossible, so large objects are depicted reduced, and small ones - enlarged, i.e. apply scale
(Fig. 29).
Rice. 29. Scale designation in the drawing
Scale– the ratio of the linear dimensions of the image of an object to its actual dimensions.
The scale of images and their designation are established by the standard (GOST 2.302-68).
natural size – 1:1(one to one);
reduction scale – 1:2; 1:25;1:4;1:5; 1:10; 1:15;
magnification scale – 2:1; 2.5:1; 4:1; 5:1; 10:1; 15:1.
The scale is indicated by the letter M on the drawing field, for example M 1:2. The letter M is not placed in the main inscription. Whatever the scale of the drawing, the actual dimensions are always indicated.
Sometimes you have to determine the scale at which an object is drawn. In this case, they do this: determine the size of the side (for example, A) using a measuring ruler, it is equal to 50 mm. The actual length of the segment indicated in the drawing is 100 mm. Consequently, the scale is determined as the quotient of dividing 50 by 100 and is equal to 1:2 (Fig. 30).
Rice. 30. Determining the scale of a part in a drawing
Every computer graphics program has a Loupe tool. It allows you to instantly change the scale of an image (drawing, picture), increasing (decreasing) it to the desired size (Fig. 31).
Rice. 31. Using scale in computer programs Loupe tool
Drawing font
In a wide variety of fields of science, technology, and design, people use fonts to write letters, numbers, symbols and other symbols.
Font– a method of encoding text information.
Each type of graphic activity is characterized by certain fonts. In many cases, artistic elements (decorations) are added to the font, giving it greater expressiveness.
The main types of fonts that were most often used throughout historical development written culture of mankind are presented in Fig. 32.
Rice. 32. Types of font
Computer fonts are popular these days. All inscriptions on the drawings are made in drawing font - GOST 2.304-81.
GOST sets the following font numbers: 1.8 (not recommended, but allowed); 2.5;3.5;5;7;10, as well as the height, width of letters and the distance between letters.
For drawings made in A4 format, the following font numbers are recommended: 2.5; 3.5; 5; 7. The standard establishes two types of font - capital ( capital letters) and lowercase. By design, uppercase and lowercase letters can be divided into three groups (Fig. 33).
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Rice. 33. Drawing font
Capital letters:
Group 1 – G, P, N, T, E, C, Sh, Shch;
Group 2 – I, X, K, F, M, A, L, D;
Group 3 – Ch, U, B, V, R, Z, O, S, E, Y, F, S, L, Ъ.
Lower case:
Group 1 – p, y, c, t, w, sch, i;
Group 2 – o, a, b, c, d, y, r, f, s;
Group 3 – f, b, i, g, g, h, j, l, m, n, x, h.
According to their proportions, they can be divided into wide and narrow: wide capitals - Ш, Ш, Ж, Ю, И, Ф; wide lowercase - t, sh, shch, yu, ы, m. The letters of the drawing font are written in a simplified form. The capital font number corresponds to the height of the letters, and the width corresponds to the smaller previous number, for example, font number 7, the height of the letters is 7, the width of the letters is 5. The width of wide letters corresponds to the height. The distance between letters is 2 mm.
The height of lowercase letters corresponds to the lower previous font number, and the width corresponds to the next previous number, for example, font number 7, letter height - 5, width - 3.5, the width of wide letters corresponds to the height of the letters. The distance between letters is 1.5 mm.
To correctly execute the letters on initial stage use a grid.
The main inscription is filled in font No. 3.5; the title of the drawing is in font No. 7 or No. 5 (Fig. 34).
Rice. 34. Sample of filling out the title block
Remember, the stitches do not touch the frame line.