# Engineering Drawing

OBJECTIVES

• To develop the ability to use various drawing instruments and materials.

• To enable in constructing and using various types of scales in drawing.

• To provide the ability to construct various geometrical figures.

• To enable to adopt various symbols used in drawing.

• To provide the skill of freehand sketching with shades and shadows.

• To provide the basic skill of drawing orthographic views.

SHORT DESCRIPTION

Drawing instruments and their uses; Lettering, numbering and constructing title strip; Adopting alphabet of lines and dimensioning; Constructing scales; Constructing geometrical figures; Constructing conic sections; Adopting symbols; Freehand sketching (with shades and shadows), Drawing orthographic views.

DETAIL DESCRIPTION

DRAWING INSTRUMENTS AND MATERIALS

1 Practice with drawing instruments and materials for basic drawing technique.

1.1 Identify the different types of drawing instruments.

1.2 Use different types of drafting equipment.

1.3 Use different types of drafting software.

1.4 Identify the standard sizes of drawing board and sheets.

1.5 Draw the border lines in drawing sheets following standard rule.

1.6 Draw horizontal, vertical and inclined lines with the help of set squares and T-square.

1.7 Draw 15 degree, 75 degree, 105 degree and 120 degree angles with the help of set squares.

1.8 Use lettering guide, template, scale pantograph and French curve.

LETTERING NUMBERING AND TITLE STRIP

2 Letter and number freehand and with instruments.

2.1 Identify the necessity of good lettering in engineering drawing.

2.2 Draw freehand single stroke vertical letters from A to Z (upper and lower case) and numbers 0 to 9.

2.3 Draw freehand inclined (65 degree to 75 degree) single stroke letters from A to Z (upper and lower case) and numbers from 0 to 9.

2.4 Draw block letters (Gothic) using 5 : 4 and 7 : 5 proportions and height.

2.5 Select a suitable size of letters and write a few sentences using all the letters selecting suitable scale.

2.6 Draw title strip with proper placement using suitable size of letters and measurements.

ALPHABET OF LINES AND DIMENSIONING

3 Adopt the alphabet of lines.

3.1 Select different lines in drawing.

3.2 Use center line, hidden line, phantom line, break line, dimension line, extension line, section line and cutting plane line.

3.3 Use different thickness of line to emphasize a part of drawing.

3.4 Select recommended grades of pencils for various types of lines for engineering drawing.

4 Adopt the elements and theory of dimensioning.

4.1 Put dimensions in engineering drawing according to an accepted standard.

4.2 Identify the elements of dimensions from a given dimensioned drawing.

4.3 Apply aligned and unidirectional system of dimensioning.

4.4 Draw size and location of dimension, continuous dimension, staggered dimension and dimensioning in limited space.

4.5 Add necessary dimension to a given drawing with suitable arrows.

CONSTRUCTION OF SCALE

5 Prepare scale for drawing application.

5.1 Calculate representative fraction and interpret a scale reading.

5.2 Use different types of scale to find full size dimension.

5.3 Draw a plain scale to show meters, centimeters and millimeters of a given distance on object.

5.4 Draw a diagonal scale to show three units having given RF.

5.5 Read particular distance on plain and diagonal scale.

5.6 Use scale of chord.

5.7 Draw angle of 49 degree, 78 degree and 95 degree with the help of scale of chord.

GEOMETRICAL CONSTRUCTIONS

6 Construct geometric figures (lines, triangles & squares).

6.1 Divide given straight line into any number of equal parts.

6.2 Draw perpendicular when the given point is at or near the end of the line.

6.3 Bisect a given angle.

6.4 Trisect a given angle.

6.5 Draw a straight line parallel to given straight line at some given distance.

6.6 Draw a square on a given straight line.

7 Construct geometric figures (circles and regular polygons).

7.1 Draw regular polygons i.e. pentagon, hexagon and octagon having given one side.

7.2 Locate the center of circle and arc.

7.3 Inscribe circle in triangles.

7.4 Inscribe a circle about a triangle.

7.5 Divide a triangle into any number of equal parts.

7.6 Draw an equilateral triangle equal in area of a square.

7.7 Determine the length of the circumference of circle.

CONIC SECTIONS

8 Construct conic sections.

8.1 Draw an ellipse by concentric circle method.

8.2 Draw an ellipse by parallelogram method.

8.3 Draw an ellipse by four center method.

8.4 Draw a parabola having given foci and directrix.

8.5 Draw a parabola from given abscissa and ordinate.

SYMBOLS

9 Adopt standard symbols in drawing.

9.1 Identify symbols used in drawing.

9.2 Draw a legend using symbols of different engineering materials.

9.3 Draw the symbols of different plumbing fittings and fixtures used in drawing.

9.4 Draw the symbols of different electrical fittings and fixtures used in drawing.

9.5 Interpret information from drawing containing standard symbols.

FREEHAND SKETCHING (WITH SHADES AND SHADOWS)

10 Sketch freehand with shades and shadows.

10.1 Produce freehand sketches of the following with shade and shadow technique:

a. Book

b. Brick

c. Step

d. Cylinder

e. Hand tubewell

f. Spade with handle

g. Pipe wrench h. Bib-cock

i. Bench vice

j. Open box

k. Electric lamps

l. Electric switches

m. Electric fan

n. Nuts and bolts

10.2 Use different materials and methods of shading and shadowing freehand sketches.

ORTHOGRAPHIC PROJECTION

11 Translate pictorial views of simple objects into orthographic views.

Identify different planes.

Draw third angle orthographic views of simple objects.

Draw first and third angle views of a simple object and add proper dimensions.

Solve missing Lines problems of different objective.

REFERENCE BOOKS

1 Geometrical Drawing

I H Morris

2 Prathamic Engineering Drawing

Hemanta Kumar Bhattacharia

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