# Problem 3.2 Engineering Curves

## Procedure:

Step-1 Draw a horizontal axis of some suitable length. And mark a point O on it.

Step-2 Draw a vertical axis, perpendicular to the horizontal axis & passing through the point O of the length equal to the length of minor axis, which is 60 mm and give points C & D as shown into the figure.

Step-3 Mark the points F1 & F2 Which are focal points on the horizontal axis and are 80 mm apart from each other.

Step-4 Measure the distance between the point F1 & C or D and with this distance keep O as center and cut the horizontal axis on both the sides and give points A & B, which is the major axis of the ellipse. Hence the distance of the major axis is 100 mm.

Step-5 With O as center and radii equal to OC and OA or OD and OB draw two circles.

Step-6 Divide these circles into 12 equal divisions as shown into the figure. And give the notations 1,2,3, etc. where these lines of divisions intersect the outer circle & 1’,2’,3’ etc. where these lines intersect the inner circle.

Step-7 Draw vertical lines from the points 2,3,5,6, in downward directions and 8,9,11,12 in upward directions respectively.

Step-8 Draw horizontal lines from the points 2’,3’,11’,12’ in left hand direction and from the points 5’,6’,8’,9’ in right hand direction respectively.

Step-9 Give the notations p1,p2,p3 etc. at the points of intersections of these horizontal & vertical lines respectively as shown into the figure.

Step-10 Draw a smooth free hand medium dark curve from the points p1,p2,p3 etc. in sequence, so the resulting curve is the ellipse.

Step-11 Give the dimensions by any one method of dimensions and give the name of the components by leader lines wherever necessary.

## Author: Vasim Machhar

An Engineering Drawing Geek. Working at Noble Group of Institutions, Junagadh as Head of Mechanical Engineering Department.