Figures 4 and 5 show how it is possible to reduce and enlarge irregular figures. Reduction and enlargement ratio of side method by saifullizza. How to draw technical drawing enlargement and reduction. Read a working or assembly drawing blueprint represent mechanical components in multiview orthographic representation create conceptual design sketches create assembly drawings limited. Whenever the drawings are set to a size smaller than the real size of the objects, they are described to have been drawn to a reduction scale. Most of engineering students get confused about scale reduction and enlargement. Scale diagrams and enlargements scale diagram a scale drawing. Construction of ellipse, parabola, hyperbola and cycloid. We have found this useful for converting fractional scale to feet per inch, inches per feet, inches per mile, meters per inch, acrescontinue. The sizechange factor for scale drawings is usually called the. The scale factor can be written as a fraction or decimal. The books are also suitable for craft level courses such as engineering and building related subjects and for industrial training courses where an understanding.
Scale is the ratio of the linear dimension of an element of an object as represented in the drawing, to the real linear dimension of the same element of the object itself. The fixed pivot, pointer, and pencil must be rigid, and, with pivot c, be of such a length that the pantograph as a whole moves parallel to the paper. In suitable proportion the dimensions should be reduced in order to adopt conveniently on the drawing sheet. When you are given a scale factor, how do you know if it is an enlargement or a reduction. Enlargement and reduction of irregular plane figures. This print out serves as a guideline for measurements of grid enlargement based on the use of a 4x6 image for reference, and either a 12x18 inch or 16x24 inch paper. It it sometimes necessary to enlarge or reduce a plane figure in one direction only.
Technical drawing is concerned mainly with using lines, circles, arcs etc. Technical drawings are drawn to scale so that engineers, architects and builders can create the objects in the drawing to exact specifications. However, it is very important that the drawing produced to be accurate and clear. Freehand sketching and drawing using instruments in. Use a method of your choice and a scale factor of 0.
A motif or a design can also be enlarged by the desired amount, say doubled in size or made four times. Technical drawings are graphic and technical communication tools. The drawing shows its name, wall bracket within the title block. Aug 23, 2018 the final part of a three part series. Intro to technical drawing elevations technical drawing elevation details and materials in elevations each elevation should show the location of all the elements of the building rooflines, windows, doors, and indicate the siding and roof materials, dimensions of windows. Pdf engineering drawing for beginners researchgate. If the scale factor is less than one, the diagram is a reduction. Objects as like buildings, town plans, bridges, maps of countries, large machine parts and their assemblies are usually drawn to decrease scales. A scale factor can be used to enlarge or reduce a shape. Working and assembling drawing and details in both first and third angles. The actual dimensions of the room say 10m x 8m cannot be adopted on the drawing. Enlargement scale full scale drawings show the actual size of an object. In order to calculate the scale factor the units must be the same. The computer keeps a record of all dimensions in the drawing changes to drawing can be made easily editing processes include the ability to copy, move, rotate, mirror and erase drawing parts drawing storage is on a hard drive, memory stick, cd, dvd or floppy disk rather than in a drawing folio.
Plane and solid geometry is the first of three books which together provide comprehensive coverage of all aspects of secondary school technical drawing. Early humans felt a need to represent the world hunting scenes to their peers. X for reduction scales x 1 dimension numbers shown in the drawing are correspond to true size of. Today you and i will quickly take a look at the topic waec syllabus for technical drawing 20202021 download waec syllabus pdf 2020. This is video is created for subject basic engineering drawing, faculty of education, utm skudai. This construction works equally well for reducing the size of a plane figure. A transformation is a way of changing the size or position of a shape. The appearance of technology gradually led humans to develop another use for drawing. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Use the new length of each line segment to draw the reduction. Students understand that a scale drawing is either the reduction or the enlargement of a twodimensional picture. This work sets out to learn and assess the use students make of the knowledge acquired in technical drawing subjects when.
If the room is represented by a rectangle of 10cm x 8cm size on the drawing sheet that means the actual size is reduced by 100 times. Technical drawing is a universal language for effective communication in the manufacturing industry and is therefore an important subject in the tvet programme at the senior high school. Geometrical drawing introduction to technical drawing and technical drawing equipment care and use of equipment. The reduction compass is made of two branches, with two points each. Nov 10, 2019 today you and i will quickly take a look at the topic waec syllabus for technical drawing 20202021 download waec syllabus pdf 2020. Students who tend work fast, or desire more of a challenge, may choose a larger piece of paper for the grid portrait project. Reduction and enlargement scales, drawing scale, assignment help. A drawing that displays technical information to the reader through specific visuals, directions, notes, etc a good technical drawing should be informative, clear, neat, unambiguous and not cluttered. Show you know tech link you can use a drawing program to enlarge or reduce an image using a scale factor.
It became a way to convey technical thought archimedes, leonardo da vinci. If the object is either too small or too large to draw full scale, the designer scales it up or down. Official website of the the ministry of education moe in guyana. Students compare the scale drawing picture with the original picture and determine if the scale drawing is a reduction or an enlargement. Figures 4 and 5 show how it is possible to reduce and enlarge. Pupils determine whether the drawing is a reduction or an enlargement and the constant of proportionality between the original and. Let a b c d e figure 4 be an irregular pentagon which has to be. This module unit involves ability to select, use, care and maintain drawing equipments and materials, construct lines and geometric shapes, use of scales and grids in perspective drawings, draw surface developments and intersection of solids, draw architectural environments, convert pictorial drawings to orthographic views and vice versa. If there is no likelihood of misunderstanding, the word scale may be omitted. You can use a drawing program to enlarge or reduce an image using a scale factor. We have a handy pdf file showing engineering and map scales, and their decimal and fractional equivalents. How to calculate scale reduction and enlargement in technical drawing. Drawing a triangle which is twice the size of the original triangle. Drawing triangles in a coordinate plane use what you learned about dilations to complete exercises 46 on page 87.
Plane and solid geometry is the first of three books which together provide comprehensive coverage of all aspects of secondary school technical drawing syllabuses. Chief examiner for the general certificate of education, ordinary level hulton preface in this technological age there is a need for well qualified engineers and scientists, and young people who wish to parti cipate in the fields of. This has become very necessary as several aspirants of the 20202021 waec examination have been trooping into our website for waec guide and asking us several other questions concerning the syllabus for waec technical drawing to help them prepare. It is a language of communication between architects and engineers, usually to convey information about the object. Round your answer to decimal places 140 200 200 350 often, we are given units of length in our diagrams. The reduction compass or proportional dividers is a geometry tool with asymmetriclength branches to allow performing homothetic transformations, reproducing a pattern while enlarging or reducing its size and conserving angles. Grid drawing challenge created for middle school, but challenging enough for high school as well. When adjusting the instrument for reduction or enlargement, make sure that the adjustment pivots are in the holes corresponding with the scale. The lesson plan introduces scale drawing to the class. The name or title of the drawing is the name by which in this case the detail drawing is commonly referred to by many parties involved. Plane and solid geometry is the first of three books which together provide comprehensive coverage of all. Technical drawing offers prerequisite knowledge and skills for a number of the technical and vocational areas of work. Enlarging and reducing plane figures and equivalent areas.
Technical drawings dgd pdf download apex tool group. T squares, set squares, pencils, rulers metric, erasers, compasses, dividers, radius gauges, protractors, scale rulers metric, layout of paper, title blocks, lettering, types of lines, plane geometry. Reduction and enlargement of regular and irregular plane figures to specified linear and area ratios. Construction of triangles, quadrilaterals and polygons. To enlarge a shape, a centre of enlargement is required. A missing length on a reductionenlargement figure can be calculated by finding its linear scale factor. Technical drawing 417 mechanical drawing the recommendations of the current bs 308a metric should be followed.
Technical drawing tutorial faculty of engineering and. This video gives basic information on the method of reduction and enlargement of plane figures by the ratio to side method. Fasteners and locking devices conven tional representatio ns. This is an easy to use chart so you can convert to different scales.
Drawing scales designation of a scale consists of the word scale followed by the indication of its ratio, as follow scale 1. Very often it is necessary to enlarge and sometimes to reduce mouldings in size but it is also essential to retain their similarity. Enlarging and reducing shapes scale factor national 4. Construction and use of scales plane and diagonal only. A scale diagram that is an enlargement or reduction of another. Intro to technical drawing elevations technical drawing elevation details and materials in elevations each elevation should show the location of all the elements of the building rooflines, windows, doors, and indicate the siding and roof materials, dimensions of windows and doors, the roof pitch, details of the trim, etc. Show full abstract memory, measuring, budgets and technical drawings. Write each scale factor as a decimal and state whether it will create an enlargement or a reduction. Aug 09, 2009 this feature is not available right now. The scale and the size of the object, in turn, will decide the size of the drawing. Loci such as the paths of points in simple link mechanisms. Dimensions and drawing to scale west orange technology. Basic technology lesson notes, basic technology objective. Reduction and enlargement of triangles, quadrilaterals, polygon etc.
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