Engineering Graphics

Let consider a simple object as shown in figure below. We will draw its orthographic views Draw thin reference line x-y. Keeping approximately 20 mm distance above reference line, draw front view as shown below After completion of front view, draw projection lines perpendicular to reference line x-y, from every corners and edges of the front view Complete top view by keeping approximately 20 mm distance below x-y After completion of top view, draw vertical reference line x 1 -y 1 , by keeping approximately 20 mm distance to left or right of the front view based upon which side view (LHSV or RHSV) is to be drawn. Draw horizontal projection lines from front view. The projectors from top view can be drawn by any method shown in Figure below Visible outlines are drawn thick Projection lines are drawn thin Hidden edges are drawn by dashed line.

Draw front view from direction-x, top view and left hand side view  Solution  

Draw a regular octagon inscribed in a circle of diameter 70 mm. Regular Octagon Inscribed in a Circle Draw a circle of diameter 70 mm. Draw the four lines of diameter (AB, CD, EF, and GH) making the angle 45 o between each other. Join the sequential ends of the line by straight lines to complete pentagon.

Inscribe a regular heptagon in a circle of diameter 60 mm Heptagon Inscribed in a circle Draw a circle of diameter 60mm. Draw a diameter line AB. By taking center A and radius AO, draw an arc EF. Draw a straight line EF, intersecting the line AB at point G. Length GE or GF is the representing length of sides of pentagon. Therefore, by taking distance equal to EG in the compass, make seven equal divisions 1, 2, 3, 4, 5, 6 and 7 on the circle. Join all the divisions by straight lines and obtain the heptagon.

Inscribe a hexagon in a circle of diameter 60 mm. Draw a circle of diameter 60 mm. With the same radius and starting from point A anywhere on the circle, set-off six divisions on the circle. Join the division points in proper sequence and complete the hexagon.

Inscribe a pentagon in a circle of diameter 70 mm. Draw a circle of diameter 70 mm. Draw the diameter lines PQ and RS, mutually perpendicular to each other. Locate mid-point T of a line PO. By taking radius TS and center T, draw an arc cutting the line PQ at U. By taking center S and radius SU, draw an arc cutting the circle at point C and E. Locate point D, overlapping on S. Locate points A and B by taking centers E & C and radius CD respectively. Join points A, B, C, D, E and A in order to complete pentagon.

Draw a circle of 60 mm diameter and inscribe a circle in it.   Let the square is ABCD. Draw a circle of diameter 60 mm. Draw two diagonals AC and BD, mutually perpendicular to each other. Join the points A, B, C, D and A by straight lines in order to complete the square ABCD.

Construct square of side 30 mm by general method. Square by General Method   Draw a line AB of length 30 mm. From point B, draw a line BM perpendicular to AB. Draw a line joining A with M. With centre B and radius AB, draw arc AM. Draw the perpendicular bisector of AB. It is intersecting to the straight line AM at O and to arc AM at Q. Point P is the midpoint of OQ. A square ABMN is inscribed in the circle drawn with centre O and radius OA. .

1. Construct a regular pentagon of side 30mm by arc method   Steps Draw a line AB of length 30 mm. With centre A and radius AB, draw a semi-circle BM. With a divider, divide the semi-circle into five equal parts (same as the number of sides). Number the division-points as 1, 2, 3, 4 and B. Draw a line joining points A and 2. Draw and extend the lines joining points A and 4, and points A and 3. With centre B and radius AB, draw an arc cutting A4 line at C. Draw a line joining points B and C. With centre C and radius AB, draw an arc cutting A3 line at D. Draw a line joining points C and D. Join points D and 2. Give a name E to point 2. Thus completing the pentagon ABCDE. 2. Construct a regular hexagon of side 25mm by arc method Draw a line AB of length 25 mm. With centre A and radius AB, draw a semi-circle BM. With a divider, divide the semi-circle into six equal parts (same as the number of sides). Number the division-points

Construct a regular pentagon of side 30mm by inscribe circle method.   Draw a line AB of length 30 mm. With centre A and radius AB, draw a semi-circle BM. With a divider, divide the semi-circle into five equal parts (same as the number of sides). Number the divisions as 1, 2, 3, 4 and 5 starting from M. Draw a line joining points A and 2. Draw the perpendicular bisectors of lines A2 and AB intersecting each other at O. With centre O and radius OA, draw a circle. With radius AB and starting from B, cut the circle at points, C, D, and E. Draw lines BC, CD, and DE. Thus, completing the required pentagon.

  With O as a centre and any radius, draw an arc cutting the lines OA and OB at points C and D respectively. With centres C and D and any convenient radius, draw the two arcs intersecting at point E. Join O and E by straight line. Line OE is bisecting angle AOB.

Divide a line AB of length 110mm into 7 equal parts.   Steps Draw a line AB of length of 110mm. Draw a line AC of any length inclined to some convenient acute angle to line AB. With the help of divider, divide a line AC into sever 7 equal parts (1’, 2’, ….7’) of any dimension. Join points C and B by straight line. Draw the lines from the divisions 6’, 5’, 4’…..1’ parallel to line CB or 7-7’ intersecting AB at 6, 5, 4, …..1. Points 1, 2, 3, 4, 5, 6, and 7 are indicating equal divisions.