Engineering drawing-part-1

Contents
1. Scales
2. Engineering Curves - I
3. Engineering Curves - II
4. Loci of Points
5. Orthographic Projections - Basics
6. Conversion of Pictorial View into Orthographic Views
7. Projections of Points and Lines
8. Projection of Planes
9. Projection of Solids
10. Sections & Development
11. Intersection of Surfaces
12. Isometric Projections
13. Exercise
14. Solutions – Applications of Lines

Scales
1. Basic Information
2. Types and important units
3. Plain Scales (3 Problems)
4. Diagonal Scales - information
5. Diagonal Scales (3 Problems)
6. Comparative Scales (3 Problems)
7. Vernier Scales - information
8. Vernier Scales (2 Problems)
9. Scales of Cords - construction
10. Scales of Cords (2 Problems)

Engineering Curves – I
1.Classification
2.Conic sections - explanation
3. Common Definition
4. Ellipse – ( six methods of construction)
5. Parabola – ( Three methods of construction)
6. Hyperbola – ( Three methods of construction )
7. Methods of drawing Tangents & Normals ( four cases)

Engineering Curves – II
1.
Classification
2. Definitions
3. Involutes - (five cases)
4. Cycloid
5. Trochoids – (Superior and Inferior)
6. Epic cycloid and Hypo - cycloid
7. Spiral (Two cases)
8. Helix – on cylinder & on cone
9. Methods of drawing Tangents and Normals (Three cases)

Loci of Points
1. Definitions - Classifications
2. Basic locus cases (six problems)
3. Oscillating links (two problems)
4. Rotating Links (two problems)

Orthographic Projections - Basics
1. Drawing – The fact about
2. Drawings - Types
3. Orthographic (Definitions and Important terms)
4. Planes - Classifications
5. Pattern of planes & views
6. Methods of orthographic projections
7. 1st
angle and 3rd
angle method – two illustrations

Conversion of pictorial views in to orthographic views.
1. Explanation of various terms
2. 1st angle method - illustration
3. 3rd angle method – illustration
4. To recognize colored surfaces and to draw three Views
5. Seven illustrations (no.1 to 7) draw different orthographic
views
6. Total nineteen illustrations ( no.8 to 26)

Projection of Points and Lines
1. Projections – Information
2. Notations
3. Quadrant Structure.
5. Projections of a Point – in 1st quadrant.
6. Lines – Objective & Types.
8. Lines inclined to one plane.
9. Lines inclined to both planes.
10. Imp. Observations for solution
11. Important Diagram & Tips.
12. Group A problems 1 to 5
13. Traces of Line ( HT & VT )
14. To locate Traces.
15. Group B problems: No. 6 to 8
16. HT-VT additional information.
17. Group B1 problems: No. 9 to 11
18. Group B1 problems: No. 9 to 1
4. Object in different Quadrants – Effect on position of views.
19. Lines in profile plane
20. Group C problems: No.12 & 13
21. Applications of Lines:: Information
22. Group D: Application Problems: 14 to 23

Projections of
Planes:
1. About the topic:
2. Illustration of surface & side inclination.
3. Procedure to solve problem & tips:
4. Problems:1 to 5: Direct inclinations:
5. Problems:6 to 11: Indirect inclinations:
6. Freely suspended cases: Info:
7. Problems: 12 & 13
8. Determination of True Shape: Info:
9. Problems: 14 to 17

Projections of Solids:
1. Classification of Solids:
2. Important parameters:
3. Positions with Hp & Vp: Info:
4. Pattern of Standard Solution.
5. Problem no 1,2,3,4: General cases:
6. Problem no 5 & 6 (cube & tetrahedron)
7. Problem no 7 : Freely suspended:
8. Problem no 8 : Side view case:
9. Problem no 9 : True length case:
10. Problem no 10 & 11 Composite solids:
11. Problem no 12 : Frustum & auxiliary plane:

Section & Development
1. Applications of solids:
2. Sectioning a solid: Information:
3. Sectioning a solid: Illustration Terms:
4. Typical shapes of sections & planes:
5. Development: Information:
6. Development of diff. solids:
7. Development of Frustums:
8. Problems: Standing Prism & Cone: no. 1 & 2
9. Problems: Lying Prism & Cone: no.3 & 4
10. Problem: Composite Solid no. 5
11. Problem: Typical cases no.6 to 9

Intersection of Surfaces:
1. Essential Information:
2. Display of Engineering Applications:
3. Solution Steps to solve Problem:
4. Case 1: Cylinder to Cylinder:
5. Case 2: Prism to Cylinder:
6. Case 3: Cone to Cylinder
7. Case 4: Prism to Prism: Axis Intersecting.
8. Case 5: Triangular Prism to Cylinder
9. Case 6: Prism to Prism: Axis Skew
10. Case 7 Prism to Cone: from top:
11. Case 8: Cylinder to Cone:

Isometric Projections
1. Definitions and explanation
2. Important Terms
3. Types.
4. Isometric of plain shapes-1.
5. Isometric of circle
6. Isometric of a part of circle
7. Isometric of plain shapes-2
8. Isometric of solids & frustums (no.5 to 16)
9. Isometric of sphere & hemi-sphere (no.17 & 18)
10. Isometric of Section of solid.(no.19)
11. Illustrated nineteen Problem (no.20 to 38)

FOR FULL SIZE SCALE
R.F.=1 OR ( 1:1 )
MEANS DRAWING
& OBJECT ARE OF
SAME SIZE.
Other RFs are described
as
1:10, 1:100,
1:1000, 1:1,00,000
SCALES
REPRESENTATIVE FACTOR (R.F.) =
=
=
=
A
USE FOLLOWING FORMULAS FOR THE CALCULATIONS IN THIS TOPIC.
B LENGTH OF SCALE = R.F. MAX. LENGTH TO BE MEASURED.X
DIMENSION OF DRAWING
DIMENSION OF OBJECT
LENGTH OF DRAWING
ACTUAL LENGTH
AREA OF DRAWING
ACTUAL AREA
VOLUME AS PER DRWG.
ACTUAL VOLUME
V
V
3

1. PLAIN SCALES ( FOR DIMENSIONS UP TO SINGLE DECIMAL)
2. DIAGONAL SCALES ( FOR DIMENSIONS UP TO TWO DECIMALS)
3. VERNIER SCALES ( FOR DIMENSIONS UP TO TWO DECIMALS)
4. COMPARATIVE SCALES ( FOR COMPARING TWO DIFFERENT UNITS)
5. SCALE OF CORDS ( FOR MEASURING/CONSTRUCTING ANGLES)
TYPES OF SCALES:
= 10 HECTOMETRES
= 10 DECAMETRES
= 10 METRES
= 10 DECIMETRES
= 10 CENTIMETRES
= 10 MILIMETRES
1 KILOMETRE
1 HECTOMETRE
1 DECAMETRE
1 METRE
1 DECIMETRE
1 CENTIMETRE
BE FRIENDLY WITH THESE UNITS.

0 1 2 3 4 510
PLAIN SCALE:- This type of scale represents two units or a unit and it’s sub-division.
METERS
DECIMETERS
R.F. = 1/100
4 M 6 DM
PLANE SCALE SHOWING METERS AND DECIMETERS.
PLAIN SCALE

PROBLEM NO.2:- In a map a 36 km distance is shown by a line 45 cms long. Calculate the R.F. and construct
a plain scale to read kilometers and hectometers, for max. 12 km. Show a distance of 8.3 km on it.
CONSTRUCTION:-
a) Calculate R.F.
R.F.= 45 cm/ 36 km = 45/ 36 . 1000 . 100 = 1/ 80,000
Length of scale = R.F. max. distance
= 1/ 80000 12 km
= 15 cm
b) Draw a line 15 cm long and divide it in 12 equal parts. Each part will represent larger division unit.
c) Sub divide the first part which will represent second unit or fraction of first unit.
d) Place ( 0 ) at the end of first unit. Number the units on right side of Zero and subdivisions
on left-hand side of Zero. Take height of scale 5 to 10 mm for getting a look of scale.
e) After construction of scale mention it’s RF and name of scale as shown.
f) Show the distance 8.3 km on it as shown.
KILOMETERS
HECTOMETERS
8KM 3HM
R.F. = 1/80,000
PLANE SCALE SHOWING KILOMETERS AND HECTOMETERS
0 1 2 3 4 5 6 7 8 9 10 1110 5
PLAIN SCALE

PROBLEM NO.3:- The distance between two stations is 210 km. A passenger train covers this distance
in 7 hours. Construct a plain scale to measure time up to a single minute. RF is 1/200,000 Indicate the distance
traveled by train in 29 minutes.
CONSTRUCTION:-
a) 210 km in 7 hours. Means speed of the train is 30 km per hour ( 60 minutes)
Length of scale = R.F. max. distance per hour
= 1/ 2,00,000 30km
= 15 cm
b) 15 cm length will represent 30 km and 1 hour i.e. 60 minutes.
Draw a line 15 cm long and divide it in 6 equal parts. Each part will represent 5 km and 10 minutes.
c) Sub divide the first part in 10 equal parts,which will represent second unit or fraction of first unit.
Each smaller part will represent distance traveled in one minute.
d) Place ( 0 ) at the end of first unit. Number the units on right side of Zero and subdivisions
on left-hand side of Zero. Take height of scale 5 to 10 mm for getting a proper look of scale.
e) Show km on upper side and time in minutes on lower side of the scale as shown.
After construction of scale mention it’s RF and name of scale as shown.
f) Show the distance traveled in 29 minutes, which is 14.5 km, on it as shown.
0 10 20 30 40 5010 MINUTESMIN
R.F. = 1/100
PLANE SCALE SHOWING METERS AND DECIMETERS.
KMKM 0 5 10 15 20 255 2.5
DISTANCE TRAVELED IN 29 MINUTES.
14.5 KM

We have seen that the plain scales give only two dimensions, such
as a unit and it’s subunit or it’s fraction.
1
2
3
4
5
6
7
8
9
10
1’
2’
3’
4’
5’
6’
7’
8’
9’
10’
X
Y
Z
The principle of construction of a diagonal scale is as follows.
Let the XY in figure be a subunit.
From Y draw a perpendicular YZ to a suitable height.
Join XZ. Divide YZ in to 10 equal parts.
Draw parallel lines to XY from all these divisions
and number them as shown.
From geometry we know that similar triangles have
their like sides proportional.
Consider two similar triangles XYZ and 7’ 7Z,
we have 7Z / YZ = 7’7 / XY (each part being one unit)
Means 7’ 7 = 7 / 10. x X Y = 0.7 XY
:.
Similarly
1’ – 1 = 0.1 XY
2’ – 2 = 0.2 XY
Thus, it is very clear that, the sides of small triangles,
which are parallel to divided lines, become progressively
shorter in length by 0.1 XY.
The diagonal scales give us three successive dimensions
that is a unit, a subunit and a subdivision of a subunit.
DIAGONAL
SCALE

R.F. = 1 / 40,00,000
DIAGONAL SCALE SHOWING KILOMETERS.
0 100 200 300 400 500100 50
10
9
8
7
6
5
4
3
2
1
0
KM
KM
KM
569 km
459 km
336 km
222 km
SOLUTION STEPS: RF = 5 cm / 200 km = 1 / 40, 00, 000
Length of scale = 1 / 40, 00, 000 X 600 X 105
= 15 cm
Draw a line 15 cm long. It will represent 600 km.Divide it in six equal parts.( each will represent 100 km.)
Divide first division in ten equal parts.Each will represent 10 km.Draw a line upward from left end and
mark 10 parts on it of any distance. Name those parts 0 to 10 as shown. Join 9th
sub-division of horizontal scale
with 10th
division of the vertical divisions. Then draw parallel lines to this line from remaining sub divisions and
complete diagonal scale.

Draw a line 15 cm long.
It will represent 600 m.Divide it in six equal parts.
( each will represent 100 m.)
Divide first division in ten equal parts.Each will
represent 10 m.
Draw a line upward from left end and
mark 10 parts on it of any distance.
Name those parts 0 to 10 as shown.Join 9th
sub-division
of horizontal scale with 10th
division of the vertical divisions.
Then draw parallel lines to this line from remaining sub divisions
and complete diagonal scale.
0 100 200 300 400 500100 50
10
9
8
7
6
5
4
3
2
1
0
M
M
M
438 meters
R.F. = 1 / 4000
DIAGONAL SCALE SHOWING METERS.

10
9
8
7
6
5
4
3
2
1
0
CENTIMETRES
MM
CM
R.F. = 1 / 2.5
DIAGONAL SCALE SHOWING CENTIMETERS.
0 5 10 155 4 3 2 1
13 .4 CM

SOLUTION STEPS:
cale of Miles:
0 miles are represented = 8 cm
80 miles = 16 cm
R.F. = 8 / 40 X 1609 X 1000 X 100
= 1 / 8, 04, 500
CONSTRUCTION:
Take a line 16 cm long and divide it into 8 parts. Each will represent 10 miles.
Subdivide the first part and each sub-division will measure single mile.
Scale of Km:
Length of scale
= 1 / 8,04,500 X 120 X 1000 X 100
= 14. 90 cm
CONSTRUCTION:
On the top line of the scale of miles cut off a distance of 14.90 cm and divide
it into 12 equal parts. Each part will represent 10 km.
Subdivide the first part into 10 equal parts. Each subdivision will show single km.
10 100 20 305 50 60 70 MILES40
10 0 10 20 30 40 50 60 70 80 90 100 110 KM
5
R.F. = 1 / 804500
COMPARATIVE SCALE SHOWING MILES AND KILOMETERS
EXAMPLE NO. 7 :
A distance of 40 miles is represented by a line
8 cm long. Construct a plain scale to read 80 miles.
Also construct a comparative scale to read kilometers
upon 120 km ( 1 m = 1.609 km )

COMPARATIVE SCALE:
EXAMPLE NO. 8 :
A motor car is running at a speed of 60 kph.
On a scale of RF = 1 / 4,00,000 show the distance
traveled by car in 47 minutes.
SOLUTION STEPS:
Scale of km.
length of scale = RF X 60 km
= 1 / 4,00,000 X 60 X 105
= 15 cm.
CONSTRUCTION:
Draw a line 15 cm long and divide it in 6 equal parts.
( each part will represent 10 km.)
Subdivide 1st
part in `0 equal subdivisions.
( each will represent 1 km.)
Time Scale:
Same 15 cm line will represent 60 minutes.
Construct the scale similar to distance scale.
It will show minimum 1 minute & max. 60min.
10 100 20 305 50 KM40
10 100 20 305 50 MINUTES40
MIN.
KM
47 MINUTES
47 KM
R.F. = 1 / 4,00,000
COMPARATIVE SCALE SHOWING MINUTES AND KILOMETERS

EXAMPLE NO. 9 :
A car is traveling at a speed of 60 km per hour. A 4 cm long line represents the distance traveled by the car in two hours.
Construct a suitable comparative scale up to 10 hours. The scale should be able to read the distance traveled in one minute.
Show the time required to cover 476 km and also distance in 4 hours and 24 minutes.
:
COMPARATIVE
SCALE
10
5
0
kM
kM 060 60 120 180 240 300 360 420 480 540
060 1 2 3 4 5 6 7 8 9
HOURS
MIN.
10
5
0
KILOMETERSDISTANCE SCALE TO MEASURE MIN 1 KM
TIME SCALE TO MEASURE MIN 1 MINUTE.
4 hrs 24 min. ( 264 kms )
476 kms ( 7 hrs 56 min.)

Figure to the right shows a part of a plain scale in
which length A-O represents 10 cm. If we divide
A-O
into ten equal parts, each will be of 1 cm. Now it
would
not be easy to divide each of these parts into ten
equal
divisions to get measurements in millimeters.
Now if we take a length BO equal to 10 + 1 = 11
such equal parts, thus representing 11 cm, and
divide it into ten equal divisions, each of these
divisions will represent 11 / 10 – 1.1 cm.
The difference between one part of AO and one
division of BO will be equal 1.1 – 1.0 = 0.1 cm or 1
mm.
This difference is called Least Count of the scale.
Vernier Scales:
These scales, like diagonal scales , are used to read to a very small unit with great accuracy.
It consists of two parts – a primary scale and a vernier. The primary scale is a plain scale fully
divided into minor divisions.
As it would be difficult to sub-divide the minor divisions in ordinary way, it is done with the help of the vernier.
The graduations on vernier are derived from those on the primary scale.
9.9 7.7 5.5 3.3 1.1
9 8 7 6 5 4 3 2 1 0A
0B

.9 .8 .7 .6 .5 .4 .3 .2 .1
.99 .77 .55 .33 .11 01.1
0 1 2 31.0 1.4
2.39 m
0.91 m
METERS
METERS
Vernier Scale

Vernier Scale
SOLUTION:
RF =
=
= 2 / 105
Length of
scale = RF X max. Distance
= 2 / 105
X 7 kms
= 14 cm
AREA OF DRAWING
ACTUAL AREAV
500 X 50 cm sq.
6250 km sq.V
CONSTRUCTION: ( Vernier)
Take 11 parts of hectometer part length
and divide it in 10 equal parts.
Each will show 1.1 hm m or 11 dm and
Covering in a rectangle complete scale.
CONSTRUCTION: ( Main scale)
Draw a line 14 cm long.
Divide it in 7 equal parts.
( each will represent km )
Sub-divide each part in 10 equal parts.
( each will represent hectometer )
Name those properly.
KILOMETERSHECTOMETERS
0 1 2 310 4 5 6
90 70 50 30 10
99 77 55 33 11
Decameters
5.33 km59 dm

100
200
300
400
500
600
700
800 900
00
0 10 20 4030 7050 60 9080
OA
CONSTRUCTION:
1. DRAW SECTOR OF A CIRCLE OF 900
WITH ‘OA’ RADIUS.
( ‘OA’ ANY CONVINIENT DISTANCE )
2. DIVIDE THIS ANGLE IN NINE EQUAL PARTS OF 10 0
EACH.
3. NAME AS SHOWN FROM END ‘A’ UPWARDS.
4. FROM ‘A’ AS CENTER, WITH CORDS OF EACH ANGLE AS RADIUS
DRAW ARCS DOWNWARDS UP TO ‘AO’ LINE OR IT’S EXTENSION
AND FORM A SCALE WITH PROPER LABELING AS SHOWN.
AS CORD LENGTHS ARE USED TO MEASURE & CONSTRUCT
DIFERENT ANGLES IT IS CALLED SCALE OF CORDS.

100
200
300
400
500
600
700
800 900
00
0 10 20 4030 7050 60 9080
OA
OA
B
O1 A1
B1
x
z
y
0
10
20
40
30
70
5060
90
80
0
10
20
40
30
70
50
60
90
80
300550
Angle at z = 180 – ( 55 + 30 ) = 950

100
200
300
400
500
600
700
800 900
00
0 10 20 4030 7050 60 9080
OA
ROBLEM 12: Construct 250
and 1150
angles with a horizontal line , by using scale of cords.
B1
750
1150
0
10
20
40
30
70
50
60
90
80
B
250
0
10
20
40
30
70
5060
90
80
A O
O
C
A
To construct 250
angle at O. To construct 1150
angle at O.

CONIC SECTIONS
ELLIPSE, PARABOLA AND HYPERBOLA ARE CALLED CONIC SECTIONS
BECAUSE
THESE CURVES APPEAR ON THE SURFACE OF A CONE
WHEN IT IS CUT BY SOME TYPICAL CUTTING PLANES.
Section PlaneSection Plane
Through GeneratorsThrough Generators
EllipseEllipse
Section Plane ParallelSection Plane Parallel
to end generator.to end generator.
Parabola
Parabola
Section PlaneSection Plane
Parallel to Axis.Parallel to Axis.
HyperbolaHyperbola
OBSERVE
ILLUSTRATIONS
GIVEN BELOW..

These are the loci of points moving in a plane such that the ratio of it’s distances
from a fixed point And a fixed line always remains constant.
The Ratio is called ECCENTRICITY. (E)
A) For Ellipse E<1
B) For Parabola E=1
C) For Hyperbola E>1
SECOND DEFINATION OF AN ELLIPSE:-
It is a locus of a point moving in a plane
such that the SUM of it’s distances from TWO fixed points
always remains constant.
{And this sum equals to the length of major axis.}
These TWO fixed points are FOCUS 1 & FOCUS 2
Refer Problem nos. 6. 9 & 12
Refer Problem no.4
Ellipse by Arcs of Circles Method.
COMMON DEFINATION OF ELLIPSE, PARABOLA & HYPERBOLA:

1
2
3
4
5
6
7
8
9
10
BA
D
C
1
2
3
4
5
6
7
8
9
10
Steps:
1. Draw both axes as perpendicular bisectors
of each other & name their ends as shown.
2. Taking their intersecting point as a center,
draw two concentric circles considering both
as respective diameters.
3. Divide both circles in 12 equal parts &
name as shown.
4. From all points of outer circle draw vertical
lines downwards and upwards respectively.
5.From all points of inner circle draw
horizontal lines to intersect those vertical
lines.
6. Mark all intersecting points properly as
those are the points on ellipse.
7. Join all these points along with the ends of
both axes in smooth possible curve. It is
required ellipse.
Problem 1 :-
Draw ellipse by concentric circle method.
Take major axis 100 mm and minor axis 70 mm
long.
ELLIPSE
BY CONCENTRIC CIRCLE METHOD

1
2
3
4
1 2 3 4
1
2
3
4
3 2 1A B
C
D
Problem 2
Draw ellipse by Rectangle method.
Take major axis 100 mm and minor axis 70
mm long.
Steps:
1 Draw a rectangle taking major
and minor axes as sides.
2. In this rectangle draw both
axes as perpendicular bisectors
of each other..
3. For construction, select upper
left part of rectangle. Divide
vertical small side and horizontal
long side into same number of
equal parts.( here divided in four
parts)
4. Name those as shown..
5. Now join all vertical points
1,2,3,4, to the upper end of minor
axis. And all horizontal points
i.e.1,2,3,4 to the lower end of
minor axis.
6. Then extend C-1 line upto D-1
and mark that point. Similarly
extend C-2, C-3, C-4 lines up to
D-2, D-3, & D-4 lines.
7. Mark all these points properly
and join all along with ends A
and D in smooth possible curve.
Do similar construction in right
side part.along with lower half of
the rectangle.Join all points in
smooth curve.
It is required ellipse.
ELLIPSE
BY RECTANGLE METHOD

C
D
1
2
3
4
1 2 3 4 3 2 1A B
1
2
3
4
Problem 3:-
Draw ellipse by Oblong method.
Draw a parallelogram of 100 mm and 70 mm
long sides with included angle of 750.
Inscribe
Ellipse in it.STEPS ARE SIMILAR TO
THE PREVIOUS CASE
(RECTANGLE METHOD)
ONLY IN PLACE OF RECTANGLE,
HERE IS A PARALLELOGRAM.
ELLIPSE
BY OBLONG METHOD

F1 F2
1 2 3 4
A B
C
D
p1
p2
p3
p4
ELLIPSE
BY ARCS OF CIRCLE METHOD
O
PROBLEM 4.
MAJOR AXIS AB & MINOR AXIS CD ARE
100 AMD 70MM LONG RESPECTIVELY
.DRAW ELLIPSE BY ARCS OF CIRLES
METHOD.
STEPS:
1.Draw both axes as usual.Name the
ends & intersecting point
2.Taking AO distance I.e.half major
axis, from C, mark F1 & F2 On AB .
( focus 1 and 2.)
3.On line F1- O taking any distance,
mark points 1,2,3, & 4
4.Taking F1 center, with distance A-1
draw an arc above AB and taking F2
center, with B-1 distance cut this arc.
Name the point p1
5.Repeat this step with same centers but
taking now A-2 & B-2 distances for
drawing arcs. Name the point p2
6.Similarly get all other P points.
With same steps positions of P can be
located below AB.
7.Join all points by smooth curve to get
an ellipse/
As per the definition Ellipse is locus of point P moving in
a plane such that the SUM of it’s distances from two fixed
points (F1 & F2) remains constant and equals to the length
of major axis AB.(Note A .1+ B .1=A . 2 + B. 2 = AB)

1
4
2
3
A B
D C
ELLIPSE
BY RHOMBUS METHOD
PROBLEM 5.
DRAW RHOMBUS OF 100 MM & 70 MM LONG
DIAGONALS AND INSCRIBE AN ELLIPSE IN IT.
STEPS:
1. Draw rhombus of given
dimensions.
2. Mark mid points of all sides &
name Those A,B,C,& D
3. Join these points to the ends of
smaller diagonals.
4. Mark points 1,2,3,4 as four
centers.
5. Taking 1 as center and 1-A
radius draw an arc AB.
6. Take 2 as center draw an arc
CD.
7. Similarly taking 3 & 4 as
centers
and 3-D radius draw arcs DA &
BC.

ELLIPSE
DIRECTRIX-FOCUS METHOD
PROBLEM 6:- POINT F IS 50 MM FROM A LINE AB.A POINT P IS MOVING IN A PLANE
SUCH THAT THE RATIO OF IT’S DISTANCES FROM F AND LINE AB REMAINS CONSTANT
AND EQUALS TO 2/3 DRAW LOCUS OF POINT P. { ECCENTRICITY = 2/3 }
F ( focus)
DIRECTRIX
V
ELLIPSE
(vertex)
A
B
STEPS:
1 .Draw a vertical line AB and point F
50 mm from it.
2 .Divide 50 mm distance in 5 parts.
3 .Name 2nd
part from F as V. It is 20mm
and 30mm from F and AB line resp.
It is first point giving ratio of it’s
distances from F and AB 2/3 i.e 20/30
4 Form more points giving same ratio such
as 30/45, 40/60, 50/75 etc.
5.Taking 45,60 and 75mm distances from
line AB, draw three vertical lines to the
right side of it.
6. Now with 30, 40 and 50mm distances in
compass cut these lines above and below,
with F as center.
7. Join these points through V in smooth
curve.
This is required locus of P.It is an ELLIPSE.
30mm
45mm

1
2
3
4
5
6
1 2 3 4 5 6
1
2
3
4
5
6
5 4 3 2 1
PARABOLA
RECTANGLE METHOD
PROBLEM 7: A BALL THROWN IN AIR ATTAINS 100 M HIEGHT
AND COVERS HORIZONTAL DISTANCE 150 M ON GROUND.
Draw the path of the ball (projectile)-
STEPS:
1.Draw rectangle of above size and
divide it in two equal vertical parts
2.Consider left part for construction.
Divide height and length in equal
number of parts and name those
1,2,3,4,5& 6
3.Join vertical 1,2,3,4,5 & 6 to the
top center of rectangle
4.Similarly draw upward vertical
lines from horizontal1,2,3,4,5
And wherever these lines intersect
previously drawn inclined lines in
sequence Mark those points and
further join in smooth possible curve.
5.Repeat the construction on right side
rectangle also.Join all in sequence.
This locus is Parabola.
.

1
2
3
4
5
6
7
8
9
10
11
12
13
14 1
2
3
4
5
6
7
8
9
10
11
12
13
14
C
A B
PARABOLA
METHOD OF TANGENTS

A
B
V
PARABOLA
(VERTEX)
F
( focus)
1 2 3 4
PARABOLA
DIRECTRIX-FOCUS METHOD
SOLUTION STEPS:
1.Locate center of line, perpendicular to
AB from point F. This will be initial
point P and also the vertex.
2.Mark 5 mm distance to its right side,
name those points 1,2,3,4 and from
those
draw lines parallel to AB.
3.Mark 5 mm distance to its left of P and
name it 1.
4.Take O-1 distance as radius and F as
center draw an arc
cutting first parallel line to AB. Name
upper point P1
and lower point P2
.
(FP1=O1)
5.Similarly repeat this process by taking
again 5mm to right and left and locate
P3
P4
.
6.Join all these points in smooth curve.
It will be the locus of P equidistance
from line AB and fixed point F.
O
P1
P2

P
O
40 mm
30 mm
1
2
3
12 1 2 3
1
2
HYPERBOLA
THROUGH A POINT
OF KNOWN CO-ORDINATES
Solution Steps:
1) Extend horizontal
line from P to right side.
2) Extend vertical line
from P upward.
3) On horizontal line
from P, mark some
points taking any
distance and name them
after P-1, 2,3,4 etc.
4) Join 1-2-3-4 points
to pole O. Let them cut
part [P-B] also at 1,2,3,4
points.
5) From horizontal
1,2,3,4 draw vertical
lines downwards and
6) From vertical 1,2,3,4
points [from P-B] draw
horizontal lines.
7) Line from 1
horizontal and line from
1 vertical will meet at
P1
.Similarly mark P2
, P3
,
P4
points.
8) Repeat the procedure
by marking four points
on upward vertical line
from P and joining all
those to pole O. Name
this points P6
, P7
, P8
etc.
and join them by smooth
Problem No.10: Point P is 40 mm and 30 mm from horizontal
and vertical axes respectively.Draw Hyperbola through it.

VOLUME:( M3
)
PRESSURE
(Kg/cm2
)
0 1 2 3 4 5 6 7 8 9 10
1
2
3
4
5
6
7
8
9
10
HYPERBOLA
P-V DIAGRAM
Problem no.11: A sample of gas is expanded in a cylinder
from 10 unit pressure to 1 unit pressure.Expansion follows
law PV=Constant.If initial volume being 1 unit, draw the
curve of expansion. Also Name the curve.
Form a table giving few more values of P & V
P V = C
+
10
5
4
2.5
2
1
1
2
2.5
4
5
10
10
10
10
10
10
10
++++++
=
=
=
=
=
=
Now draw a Graph of
Pressure against Volume.
It is a PV Diagram and it is Hyperbola.
Take pressure on vertical axis and
Volume on horizontal axis.

F ( focus)V
(vertex)
A
B
30mm
45mm
HYPERBOLA
DIRECTRIX
FOCUS METHOD
POINT F IS 50 MM FROM A LINE AB.A POINT P IS MOVING IN A PLANE
E RATIO OF IT’S DISTANCES FROM F AND LINE AB REMAINS CONSTANT
O 2/3 DRAW LOCUS OF POINT P. { ECCENTRICITY = 2/3 }
STEPS:
1 .Draw a vertical line AB and point F
50 mm from it.
2 .Divide 50 mm distance in 5 parts.
3 .Name 2nd
part from F as V. It is 20mm
and 30mm from F and AB line resp.
It is first point giving ratio of it’s
distances from F and AB 2/3 i.e 20/30
4 Form more points giving same ratio such
as 30/45, 40/60, 50/75 etc.
5.Taking 45,60 and 75mm distances from
line AB, draw three vertical lines to the
right side of it.
6. Now with 30, 40 and 50mm distances in
compass cut these lines above and below,
with F as center.
7. Join these points through V in smooth
curve.
This is required locus of P.It is an ELLIPSE.

D
F1 F2
1 2 3 4
A B
C
p1
p2
p3
p4
O
Q TANGENT
NORMAL
TO DRAW TANGENT & NORMAL
TO THE CURVE FROM A GIVEN POINT ( Q )
1. JOIN POINT Q TO F1 & F2
2. BISECT ANGLE F1Q F2 THE ANGLE BISECTOR IS NORMAL
3. A PERPENDICULAR LINE DRAWN TO IT IS TANGENT TO THE CURVE.
ELLIPSE
TANGENT & NORMAL
Problem 13:

ELLIPSE
TANGENT & NORMAL
F ( focus)
DIRECTRIX
V
ELLIPSE
(vertex)
A
B
T
T
N
N
Q
900
TO THE CURVE
FROM A GIVEN POINT ( Q )
1.JOIN POINT Q TO F.
2.CONSTRUCT 900 ANGLE WITH
THIS LINE AT POINT F
3.EXTEND THE LINE TO MEET DIRECTRIX
AT T
4. JOIN THIS POINT TO Q AND EXTEND. THIS IS
TANGENT TO ELLIPSE FROM Q
5.TO THIS TANGENT DRAW PERPENDICULAR
LINE FROM Q. IT IS NORMAL TO CURVE.
Problem 14:

A
B
PARABOLA
VERTEX F
( focus)
V
Q
T
N
N
T
900
TO THE CURVE
2.CONSTRUCT 900
ANGLE WITH
THIS LINE AT POINT F
3.EXTEND THE LINE TO MEET DIRECTRIX
AT T
TANGENT TO THE CURVE FROM Q
PARABOLA
TANGENT & NORMALProblem 15:

F ( focus)V
(vertex)
A
B
HYPERBOLA
TANGENT & NORMAL
QN
N
T
T
900
TO THE CURVE
2.CONSTRUCT 900
ANGLE WITH THIS LINE AT
POINT F
3.EXTEND THE LINE TO MEET DIRECTRIX AT T
TANGENT TO CURVE FROM Q
Problem 16

INVOLUTE CYCLOID SPIRAL HELIX
ENGINEERING CURVES
Part-II
(Point undergoing two types of displacements)
1. Involute of a circle
a)String Length = πD
b)String Length > πD
c)String Length < πD
2. Pole having Composite
shape.
3. Rod Rolling over
a Semicircular Pole.
1. General Cycloid
2. Trochoid
( superior)
3. Trochoid
( Inferior)
4. Epi-Cycloid
5. Hypo-Cycloid
1. Spiral of
One Convolution.
2. Spiral of
Two Convolutions.
1. On Cylinder
2. On a Cone
AND

CYCLOID:
IT IS A LOCUS OF A POINT ON THE
PERIPHERY OF A CIRCLE WHICH
ROLLS ON A STRAIGHT LINE PATH.
INVOLUTE:
IT IS A LOCUS OF A FREE END OF A STRING
WHEN IT IS WOUND ROUND A CIRCULAR POLE
SPIRAL:
IT IS A CURVE GENERATED BY A POINT
WHICH REVOLVES AROUND A FIXED POINT
AND AT THE SAME MOVES TOWARDS IT.
HELIX:
IT IS A CURVE GENERATED BY A POINT WHICH
MOVES AROUND THE SURFACE OF A RIGHT CIRCULAR
CYLINDER / CONE AND AT THE SAME TIME ADVANCES IN AXIAL DIRECTION
DEFINITIONS

INVOLUTE OF A CIRCLEProblem no 17: Draw Involutes of a circle.
String length is equal to the circumference of circle.
1 2 3 4 5 6 7 8
P
P8
1
2
3
4
5
6
7
8
P3
3
to
p
P4
4 to p
P5
5to
p
P7
7
to
p
P6
6top
P2
2top
P1
1to
p
π
D
A
Solution Steps:
1) Point or end P of string AP is exactly
πD distance away from A. Means if this
string is wound round the circle, it will
completely cover given circle. B will
meet A after winding.
2) Divide πD (AP) distance into 8
number of equal parts.
3) Divide circle also into 8 number of
equal parts.
4) Name after A, 1, 2, 3, 4, etc. up to 8
on πD line AP as well as on circle (in
anticlockwise direction).
5) To radius C-1, C-2, C-3 up to C-8
draw tangents (from 1,2,3,4,etc to
circle).
6) Take distance 1 to P in compass and
mark it on tangent from point 1 on
circle (means one division less than
distance AP).
7) Name this point P1
8) Take 2-B distance in compass and
mark it on the tangent from point 2.
Name it point P2.
9) Similarly take 3 to P, 4 to P, 5 to P up
to 7 to P distance in compass and mark
on respective tangents and locate P3,
P4, P5 up to P8 (i.e. A) points and join
them in smooth curve it is an INVOLUTE
of a given circle.

INVOLUTE OF A CIRCLE
String length MORE than πD
1 2 3 4 5 6 7 8
P
1
2
3
4
5
6
7
8
P3
3
to
p
P4
4 to p
P5
5to
p
P7
7
to
p
P6
6top
P2
2top
P1
1to
p
165 mm
(more than πD)
πD
p8
Solution Steps:
In this case string length is more
than Π D.
But remember!
Whatever may be the length of
string, mark Π D distance
horizontal i.e.along the string
and divide it in 8 number of
equal parts, and not any other
distance. Rest all steps are same
as previous INVOLUTE. Draw
the curve completely.
Problem 18: Draw Involutes of a circle.
String length is MORE than the circumference of circle.

1 2 3 4 5 6 7 8
P
1
2
3
4
5
6
7
8
P3
3
to
p
P4
4 to p
P5
5to
p
P7
7
to
p
P6
6top
P2
2top
P1
1top
150 mm
(Less than πD)
πD
String length LESS than πD
oblem 19: Draw Involutes of a circle.
tring length is LESS than the circumference of circle.
Solution Steps:
In this case string length is Less
than Π D.
But remember!
Whatever may be the length of
string, mark Π D distance
horizontal i.e.along the string
and divide it in 8 number of
equal parts, and not any other
distance. Rest all steps are same
as previous INVOLUTE. Draw
the curve completely.

1
2
34
5
6
1 2 3 4 5 6
A
P
πD/2
P1
1toP
P2
2
to
P
P3
3 to P
P4
4toP
P
AtoPP5
5toP
P6
6toP
INVOLUTE
OF
COMPOSIT SHAPED POLE
PROBLEM 20 : A POLE IS OF A SHAPE OF HALF HEXABON AND SEMICIRCLE.
ASTRING IS TO BE WOUND HAVING LENGTH EQUAL TO THE POLE PERIMETER
DRAW PATH OF FREE END P OF STRING WHEN WOUND COMPLETELY.
(Take hex 30 mm sides and semicircle of 60 mm diameter.)
SOLUTION STEPS:
Draw pole shape as per
dimensions.
Divide semicircle in 4
parts and name those
along with corners of
hexagon.
Calculate perimeter
length.
Show it as string AP.
On this line mark 30mm
from A
Mark and name it 1
Mark πD/2 distance on it
from 1
And dividing it in 4 parts
name 2,3,4,5.
Mark point 6 on line 30
mm from 5
Now draw tangents from
all points of pole
and proper lengths as
done in all previous
involute’s problems and
complete the curve.

1
2
3
4
πD
1
2
3
4
A
B
A1
B1
A2 B2
A3
B3
A4
B4
PROBLEM 21 : Rod AB 85 mm long rolls over
a semicircular pole without slipping from
it’s initially vertical position till it becomes
up-side-down vertical.
Draw locus of both ends A & B.
Solution Steps?
If you have studied previous problems
properly, you can surely solve this also.
Simply remember that this being a rod,
it will roll over the surface of pole.
Means when one end is approaching,
other end will move away from poll.
OBSERVE ILLUSTRATION CAREFULLY!

P
C1 C2 C3 C4 C5 C6 C7 C8
p1
p2
p3
p4
p5
p6
p7
p8
1
2
3
4
5
6
7
C
πD
CYCLOID
PROBLEM 22: DRAW LOCUS OF A POINT ON THE PERIPHERY OF A CIRCLE
WHICH ROLLS ON STRAIGHT LINE PATH. Take Circle diameter as 50 mm
Solution Steps:
1) From center C draw a horizontal line equal to πD distance.
2) Divide πD distance into 8 number of equal parts and name them C1, C2, C3__ etc.
3) Divide the circle also into 8 number of equal parts and in clock wise direction, after P name 1, 2, 3 up to 8.
4) From all these points on circle draw horizontal lines. (parallel to locus of C)
5) With a fixed distance C-P in compass, C1 as center, mark a point on horizontal line from 1. Name it P.
6) Repeat this procedure from C2, C3, C4 upto C8 as centers. Mark points P2, P3, P4, P5 up to P8 on the
horizontal lines drawn from 2, 3, 4, 5, 6, 7 respectively.
7) Join all these points by curve. It is Cycloid.

C1 C2 C3 C4 C5 C6 C7 C8
p1
p2
p3
p4
p5
p6
p7
p8
1
2
3
4
5
6
7
C
πD
SUPERIOR TROCHOID
P
PROBLEM 23: DRAW LOCUS OF A POINT , 5 MM AWAY FROM THE PERIPHERY OF A
CIRCLE WHICH ROLLS ON STRAIGHT LINE PATH. Take Circle diameter as 50 mm
Solution Steps:
1) Draw circle of given diameter and draw a horizontal line from it’s center C of length Π D and divide it
in 8 number of equal parts and name them C1, C2, C3, up to C8.
2) Draw circle by CP radius, as in this case CP is larger than radius of circle.
3) Now repeat steps as per the previous problem of cycloid, by dividing this new circle into 8 number of
equal parts and drawing lines from all these points parallel to locus of C and taking CP radius wit
different positions of C as centers, cut these lines and get different positions of P and join
4) This curve is called Superior Trochoid.

P
C1 C2 C3 C4 C5 C6 C7 C8
p1
p2
p3
p4
p5
p6
p7
p8
1
2
3
4
5
6
7
C
πD
INFERIOR TROCHOID
PROBLEM 24: DRAW LOCUS OF A POINT , 5 MM INSIDE THE PERIPHERY OF A
CIRCLE WHICH ROLLS ON STRAIGHT LINE PATH. Take Circle diameter as 50 mm
Solution Steps:
1) Draw circle of given diameter and draw a horizontal line from it’s center C of length Π D and divide it
in 8 number of equal parts and name them C1, C2, C3, up to C8.
2) Draw circle by CP radius, as in this case CP is SHORTER than radius of circle.
3) Now repeat steps as per the previous problem of cycloid, by dividing this new circle into 8 number
of equal parts and drawing lines from all these points parallel to locus of C and taking CP radius
with different positions of C as centers, cut these lines and get different positions of P and join
those in curvature.
4) This curve is called Inferior Trochoid.

C
C1
C2
C3 C4
C
5
C
8
C6
C7
EPI CYCLOID
P
O
R
r = CP
+
r
R
3600
=
1
2
3
4 5
6
7
Generating/
Rolling Circle
Directing Circle
WHICH ROLLS ON A CURVED PATH. Take diameter of rolling Circle 50 mm
And radius of directing circle i.e. curved path, 75 mm.
Solution Steps:
1) When smaller circle will roll on larger
circle for one revolution it will cover Π D
distance on arc and it will be decided by
included arc angle θ.
2) Calculate θ by formula θ = (r/R) x 3600.
3) Construct angle θ with radius OC and
draw an arc by taking O as center OC as
radius and form sector of angle θ.
4) Divide this sector into 8 number of
equal angular parts. And from C onward
name them C1, C2, C3 up to C8.
5) Divide smaller circle (Generating circle)
also in 8 number of equal parts. And next
to P in clockwise direction name those 1,
2, 3, up to 8.
6) With O as center, O-1 as radius draw an
arc in the sector. Take O-2, O-3, O-4, O-5
up to O-8 distances with center O, draw all
concentric arcs in sector. Take fixed
distance C-P in compass, C1 center, cut arc
of 1 at P1.
Repeat procedure and locate P2, P3, P4,
P5 unto P8 (as in cycloid) and join them by
smooth curve. This is EPI – CYCLOID.

HYPO CYCLOID
C
P1
P2
P3
P4
P5
P6 P7
P8
P
1
2
3
6
5
7
4
C1
C2 C3
C4
C
5
C
6
C
7
C8
O
OC = R ( Radius of Directing Circle)
CP = r (Radius of Generating Circle)
+
r
R
3600
=
WHICH ROLLS FROM THE INSIDE OF A CURVED PATH. Take diameter of
rolling circle 50 mm and radius of directing circle (curved path) 75 mm.
Solution Steps:
1) Smaller circle is rolling
here, inside the larger circle.
It has to rotate anticlockwise
to move ahead.
2) Same steps should be
taken as in case of EPI –
CYCLOID. Only change is in
numbering direction of 8
number of equal parts on the
smaller circle.
3) From next to P in
anticlockwise direction,
name 1,2,3,4,5,6,7,8.
4) Further all steps are that
of epi – cycloid. This is called
HYPO – CYCLOID.

7 6 5 4 3 2 1
P
1
2
3
4
5
6
7
P2
P6
P1
P3
P5
P7
P4 O
olution Steps
With PO radius draw a circle
and divide it in EIGHT parts.
Name those 1,2,3,4, etc. up to 8
Similarly divided line PO also in
EIGHT parts and name those
1,2,3,-- as shown.
Take o-1 distance from op line
and draw an arc up to O1 radius
vector. Name the point P1
Similarly mark points P2, P3, P4
up to P8
And join those in a smooth curve.
t is a SPIRAL of one convolution.
IMPORTANT APPROACH FOR CONSTRUCTION!
FIND TOTAL ANGULAR AND TOTAL LINEAR DISPLACEMENT
AND DIVIDE BOTH IN TO SAME NUMBER OF EQUAL PARTS.

16 13 10 8 7 6 5 4 3 2 1 P
1,9
2,10
3,11
4,12
5,13
6,14
7,15
8,16
P1
P2
P3
P4
P5
P6
P7
P8
P9
P10
P11
P12
P13 P14
P15
Problem 28
Point P is 80 mm from point O. It starts moving towards O and reaches it in two
revolutions around.it Draw locus of point P (To draw a Spiral of TWO convolutions).
IMPORTANT APPROACH FOR CONSTRUCTION!
FIND TOTAL ANGULAR AND TOTAL LINEAR DISPLACEMENT
AND DIVIDE BOTH IN TO SAME NUMBER OF EQUAL PARTS.
SOLUTION STEPS:
Total angular displacement here
is two revolutions And
Total Linear displacement here
is distance PO.
Just divide both in same parts i.e.
Circle in EIGHT parts.
( means total angular displacement
in SIXTEEN parts)
Divide PO also in SIXTEEN parts.
Rest steps are similar to the previous
problem.

1
2
3
4
5
6
7
8
P
P1
P
P2
P3
P4
P5
P6
P7
P8
1
2
3
4
5
6
7
HELIX
(UPON A CYLINDER)
PROBLEM: Draw a helix of one convolution, upon a cylinder.
Given 80 mm pitch and 50 mm diameter of a cylinder.
(The axial advance during one complete revolution is called
The pitch of the helix)
SOLUTION:
Draw projections of a cylinder.
Divide circle and axis in to same no. of equal parts. ( 8 )
Name those as shown.
Mark initial position of point ‘P’
Mark various positions of P as shown in animation.
Join all points by smooth possible curve.
Make upper half dotted, as it is going behind the solid
and hence will not be seen from front side.

P
1
2
3
4
5
6
7
1
2
3
4
5
6
7
8
P
P1
P2
P3
P4
P5
P6
P7
P8
P1
P2
P3
P4
P5P6
P7
P8
X Y
HELIX
(UPON A CONE)PROBLEM: Draw a helix of one convolution, upon a cone,
diameter of base 70 mm, axis 90 mm and 90 mm pitch.
(The axial advance during one complete revolution is called
The pitch of the helix)
SOLUTION:
Draw projections of a cone
Divide circle and axis in to same no. of equal parts. ( 8 )
Name those as shown.
Mark initial position of point ‘P’
Mark various positions of P as shown in animation.
Join all points by smooth possible curve.
Make upper half dotted, as it is going behind the solid
and hence will not be seen from front side.

Tangent
Normal
Q
STEPS:
DRAW INVOLUTE AS USUAL.
MARK POINT Q ON IT AS DIRECTED.
JOIN Q TO THE CENTER OF CIRCLE C.
CONSIDERING CQ DIAMETER, DRAW
A SEMICIRCLE AS SHOWN.
MARK POINT OF INTERSECTION OF
THIS SEMICIRCLE AND POLE CIRCLE
AND JOIN IT TO Q.
THIS WILL BE NORMAL TO INVOLUTE.
DRAW A LINE AT RIGHT ANGLE TO
THIS LINE FROM Q.
IT WILL BE TANGENT TO INVOLUTE.
1 2 3 4 5 6 7 8
P
P8
1
2
3
4
5
6
7
8
π
D
C

Q
N Normal
Tangent
CYCLOID
Method of Drawing
Tangent & Normal
STEPS:
DRAW CYCLOID AS USUAL.
MARK POINT Q ON IT AS DIRECTED.
WITH CP DISTANCE, FROM Q. CUT THE
POINT ON LOCUS OF C AND JOIN IT TO Q.
FROM THIS POINT DROP A PERPENDICULAR
ON GROUND LINE AND NAME IT N
JOIN N WITH Q.THIS WILL BE NORMAL TO
CYCLOID.
DRAW A LINE AT RIGHT ANGLE TO
THIS LINE FROM Q.
IT WILL BE TANGENT TO CYCLOID.
P
C1 C2 C3 C4 C5 C6 C7 C8
πD
CYCLOID
C
CP

7 6 5 4 3 2 1
P
1
2
3
4
5
6
7
P2
P6
P1
P3
P5
P7
P4 O
SPIRAL (ONE CONVOLUSION.)
Normal
Tangent
Q
Spiral.
Method of Drawing
Tangent & Normal

LOCUS
It is a path traced out by a point moving in a plane,
in a particular manner, for one cycle of operation.
The cases are classified in THREE categories for easy understanding.
A} Basic Locus Cases.
B} Oscillating Link……
C} Rotating Link………
Basic Locus Cases:
Here some geometrical objects like point, line, circle will be described with there relative
Positions. Then one point will be allowed to move in a plane maintaining specific relation
with above objects. And studying situation carefully you will be asked to draw it’s locus.
Oscillating & Rotating Link:
Here a link oscillating from one end or rotating around it’s center will be described.
Then a point will be allowed to slide along the link in specific manner. And now studying
the situation carefully you will be asked to draw it’s locus.
STUDY TEN CASES GIVEN ON NEXT PAGES

A
B
p
4 3 2 1
F1 2 3 4
SOLUTION STEPS:
AB from point F. This will be initial
point P.
name those points 1,2,3,4 and from those
name it 1.
4.Take F-1 distance as radius and F as
center draw an arc
cutting first parallel line to AB. Name
upper point P1
and lower point P2
.
P3
P4
.
from line AB and fixed point F.
P1
P2
P3
P4
P5
P6
P7
P8
PROBLEM 1.: Point F is 50 mm from a vertical straight line AB.
Draw locus of point P, moving in a plane such that
it always remains equidistant from point F and line AB.
Basic Locus Cases:

A
B
p
4 3 2 1 1 2 3 4
P1
P2
P3
P4
P5
P6
P7
P8
C
SOLUTION STEPS:
AB from the periphery of circle. This
will be initial point P.
name those points 1,2,3,4 and from those
name it 1,2,3,4.
4.Take C-1 distance as radius and C as
center draw an arc cutting first parallel
line to AB. Name upper point P1
and
lower point P2
.
P3
P4
.
from line AB and given circle.
50 D
75 mm
PROBLEM 2 :
A circle of 50 mm diameter has it’s center 75 mm from a vertical
line AB.. Draw locus of point P, moving in a plane such that
it always remains equidistant from given circle and line AB.
Basic Locus Cases:

95 mm
30 D
60 D
p
4 3 2 1 1 2 3 4
C2C1
P1
P2
P3
P4
P5
P6
P7
P8
PROBLEM 3 :
Center of a circle of 30 mm diameter is 90 mm away from center of another circle of 60 mm diameter.
Draw locus of point P, moving in a plane such that it always remains equidistant from given two circles.
SOLUTION STEPS:
1.Locate center of line,joining two
centers but part in between periphery
of two circles.Name it P. This will be
initial point P.
2.Mark 5 mm distance to its right
side, name those points 1,2,3,4 and
from those draw arcs from C1
As center.
3. Mark 5 mm distance to its right
side, name those points 1,2,3,4 and
from those draw arcs from C2 As
center.
4.Mark various positions of P as per
previous problems and name those
similarly.
5.Join all these points in smooth
curve.
It will be the locus of P
equidistance from given two circles.
Basic Locus Cases:

P
A B
4 3 2 1 1 2 3 4
70 mm 30 mm
p1
p2
p3
p4
p5
p6
p7
p8
Problem 5:-Two points A and B are 100 mm apart.
There is a point P, moving in a plane such that the
difference of it’s distances from A and B always
remains constant and equals to 40 mm.
Draw locus of point P.
Basic Locus Cases:
Solution Steps:
1.Locate A & B points 100 mm apart.
2.Locate point P on AB line,
70 mm from A and 30 mm from B
As PA-PB=40 ( AB = 100 mm )
3.On both sides of P mark points 5
mm apart. Name those 1,2,3,4 as usual.
4.Now similar to steps of Problem 2,
Draw different arcs taking A & B centers
and A-1, B-1, A-2, B-2 etc as radius.
5. Mark various positions of p i.e. and join
them in smooth possible curve.
It will be locus of P

1) Mark lower most
position of M on extension
of AB (downward) by taking
distance MN (40 mm) from
point B (because N can
not go beyond B ).
2) Divide line (M initial
and M lower most ) into
eight to ten parts and mark
them M1
, M2
, M3
up to the
last position of M .
3) Now take MN (40 mm)
as fixed distance in compass,
M1
center cut line CB in N1
.
4) Mark point P1
on M1
N1
with same distance of MP
from M1
.
5) Similarly locate M2
P2,
M3
P3
, M4
P4
and join all P
points.
It will be
locus of P.
Solution Steps:
600
900
M
N
N1
N2
N3
N4
N5
N6
N7
N8
N9
N10
N11
N12
A
B
C
D
M1
M2
M3
M4
M5
M7
M8
M9
M10
M11
M6
M12
M13
N13
p
p1
p2
p3
p4
p5
p6
p7
p8
p9
p10
p13
p11
p12
Problem 6:-Two points A and B are 100 mm apart.
There is a point P, moving in a plane such that the
difference of it’s distances from A and B always
remains constant and equals to 40 mm.
FORK & SLIDER

1
2
3
4
5
6
7
8
p
p1
p2
p3
p4
p5
p6
p7
p8
O
A A1
A2
A3
A4
A5
A6
A7
A8
Problem No.7:
A Link OA, 80 mm long oscillates around O,
600
to right side and returns to it’s initial vertical
Position with uniform velocity.Mean while point
P initially on O starts sliding downwards and
reaches end A with uniform velocity.
Draw locus of point P
Solution Steps:
Point P- Reaches End A (Downwards)
1) Divide OA in EIGHT equal parts and from O to A after O
name 1, 2, 3, 4 up to 8. (i.e. up to point A).
2) Divide 600
angle into four parts (150
each) and mark each
point by A1
, A2
, A3
, A4
and for return A5
, A6
, A7
andA8
.
(Initial A point).
3) Take center O, distance in compass O-1 draw an arc upto
OA1
. Name this point as P1.
1) Similarly O center O-2 distance mark P2
on line O-A2
.
2) This way locate P3
, P4
, P5
, P6
, P7
and P8
and join them.
( It will be thw desired locus of P )
OSCILLATING LINK

p
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
O
A
Problem No 8:
A Link OA, 80 mm long oscillates around O,
600
to right side, 1200
to left and returns to it’s initial
vertical Position with uniform velocity.Mean while point
P initially on O starts sliding downwards, reaches end A
and returns to O again with uniform velocity.
Draw locus of point P
Solution Steps:
( P reaches A i.e. moving downwards.
& returns to O again i.e.moves upwards )
1.Here distance traveled by point P is PA.plus
AP.Hence divide it into eight equal parts.( so
total linear displacement gets divided in 16
parts) Name those as shown.
2.Link OA goes 600
to right, comes back to
original (Vertical) position, goes 600
to left
and returns to original vertical position. Hence
total angular displacement is 2400
.
Divide this also in 16 parts. (150
each.)
Name as per previous problem.(A, A1 A2 etc)
3.Mark different positions of P as per the
procedure adopted in previous case.
and complete the problem.
A2
A1
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
A15
A16
p8
p5
p6
p7
p2
p4
p1
p3
OSCILLATING LINK

A B
A1
A2
A4
A5
A3
A6
A7
P
p1 p2
p3
p4
p5
p6
p7
p8
1 2 3
4 5 6 7
Problem 9:
Rod AB, 100 mm long, revolves in clockwise direction for one revolution.
Meanwhile point P, initially on A starts moving towards B and reaches B.
ROTATING LINK
1)  AB Rod revolves around center
O for one revolution and point P
slides along AB rod and reaches
end B in one revolution.
2)  Divide circle in 8 number of
equal parts and name in arrow
direction after A-A1, A2, A3, up to
A8.
3)  Distance traveled by point P is
AB mm. Divide this also into 8
number of equal parts.
4)  Initially P is on end A. When A
moves   to A1, point P goes one
linear division (part) away from
A1. Mark it from A1 and name the
point P1.
5)   When A moves to A2, P will be
two parts away from A2 (Name it
P2 ). Mark it as above from A2.
6)   From A3 mark P3 three parts
away from P3.
7)   Similarly locate P4, P5, P6, P7
and P8 which will be eight parts
away from A8. [Means P has
reached B].
8)   Join all P points by smooth
curve. It will be locus of P

A B
A1
A2
A4
A5
A3
A6
A7
P
p1
p2
p3
p4
p5
p6
p7
p8
1 2 3 4567
Problem 10 :
Rod AB, 100 mm long, revolves in clockwise direction for one revolution.
Meanwhile point P, initially on A starts moving towards B, reaches B
And returns to A in one revolution of rod.
Solution Steps
+ + + +
ROTATING LINK
1)   AB Rod revolves around center O for
one revolution and point P slides along
rod AB reaches end B and returns to A.
2)   Divide circle in 8 number of equal
parts and name in arrow direction after
A-A1, A2, A3, up to A8.
3)   Distance traveled by point P is AB
plus AB mm. Divide AB in 4 parts so
those will be  8 equal parts on return.
4)   Initially P is on end A. When A moves
to A1, point P goes one linear division
(part) away from A1. Mark it from A1 and
name the point P1.
5)   When A moves to A2, P will be two
parts away from A2 (Name it P2 ). Mark
it as above from A2.
6)   From A3 mark P3 three parts away
from P3.
7)   Similarly locate P4, P5, P6, P7 and P8
which will be eight parts away from A8.
[Means P has reached B].
8)   Join all P points by smooth curve. It
will be locus of P
           The Locus will follow the loop path
two times in one revolution.

DRAWINGS:
( A Graphical Representation)
The Fact about:
If compared with Verbal or Written Description,
Drawings offer far better idea about the Shape, Size & Appearance of
any object or situation or location, that too in quite a less time.
Hence it has become the Best Media of Communication
not only in Engineering but in almost all Fields.

Drawings
(Some Types)
Nature Drawings
( landscape,
scenery etc.)
Geographical
Drawings
( maps etc.)
Botanical Drawings
( plants, flowers etc.)
Zoological Drawings
(creatures, animals etc.)
Portraits
( human faces,
expressions etc.)
Engineering Drawings,
(projections.)
Machine component DrawingsBuilding Related Drawings.
Orthographic Projections
(Fv,Tv & Sv.-Mech.Engg terms)
(Plan, Elevation- Civil Engg.terms)
(Working Drawings 2-D type)
Isometric ( Mech.Engg.Term.)
or Perspective(Civil Engg.Term)
(Actual Object Drawing 3-D)

ORTHOGRAPHIC PROJECTIONS:
Horizontal Plane (HP),
Vertical Frontal Plane ( VP )
Side Or Profile Plane ( PP)
Planes.
   Pattern of planes & Pattern of views
     Methods of drawing Orthographic Projections

Different Reference planes are
FV is a view projected on VP.
TV is a view projected on HP.
SV is a view projected on PP.
And
Different Views are Front View (FV), Top View (TV) and Side View (SV)
IMPORTANT TERMS OF ORTHOGRAPHIC PROJECTIONS:
IT IS A TECHNICAL DRAWING IN WHICH DIFFERENT VIEWS OF AN OBJECT
ARE PROJECTED ON DIFFERENT REFERENCE PLANES
OBSERVING PERPENDICULAR TO RESPECTIVE REFERENCE PLANE
1
2
3


A.I.P.⊥ to Vp & ∠ to Hp

A.V.P.
⊥ to Hp & ∠ to Vp
PLANES
PRINCIPAL PLANES
HP AND VP
AUXILIARY PLANES
Auxiliary Vertical Plane
(A.V.P.)
Profile Plane
( P.P.)
Auxiliary Inclined Plane
(A.I.P.)
1

THIS IS A PICTORIAL SET-UP OF ALL THREE PLANES.
ARROW DIRECTION IS A NORMAL WAY OF OBSERVING THE OBJECT.
BUT IN THIS DIRECTION ONLY VP AND A VIEW ON IT (FV) CAN BE SEEN.
THE OTHER PLANES AND VIEWS ON THOSE CAN NOT BE SEEN.
X
Y
HP IS ROTATED DOWNWARD 900
AND
BROUGHT IN THE PLANE OF VP.
PP IS ROTATED IN RIGHT SIDE 900
AND
BROUGHT IN THE PLANE OF VP.
X
Y
X Y
VP
HP
PP
FV
ACTUAL PATTERN OF PLANES & VIEWS
OF ORTHOGRAPHIC PROJECTIONS
DRAWN IN
FIRST ANGLE METHOD OF PROJECTIONS
LSV
TV
PROCEDURE TO SOLVE ABOVE PROBLEM:-
TO MAKE THOSE PLANES ALSO VISIBLE FROM THE ARROW DIRECTION,
A) HP IS ROTATED 900
DOUNWARD
B) PP, 900
IN RIGHT SIDE DIRECTION.
THIS WAY BOTH PLANES ARE BROUGHT IN THE SAME PLANE CONTAINING VP.
PATTERN OF PLANES & VIEWS (First Angle Method)
2
Click to view Animation On clicking the button if a warning comes please click YES to continue, this program is
safe for your pc.

Methods of Drawing Orthographic Projections
First Angle Projections Method
Here views are drawn
by placing object
in 1st
Quadrant
( Fv above X-y, Tv below X-y )
Third Angle Projections Method
Here views are drawn
by placing object
in 3rd
Quadrant.
( Tv above X-y, Fv below X-y )
FV
TV
X Y X Y
G L
TV
FV
SYMBOLIC
PRESENTATION
OF BOTH METHODS
WITH AN OBJECT
STANDING ON HP ( GROUND)
ON IT’S BASE.
3
NOTE:-
HP term is used in 1st
Angle method
&
For the same
Ground term is used
in 3rd
Angle method of projections

FOR T.V.
FOR
S.V. FOR
F.V.
FIRST ANGLE
PROJECTION
IN THIS METHOD,
THE OBJECT IS ASSUMED TO BE
SITUATED IN FIRST QUADRANT
MEANS
ABOVE HP & INFRONT OF VP.
OBJECT IS INBETWEEN
OBSERVER & PLANE.
ACTUAL PATTERN OF
PLANES & VIEWS
IN
FIRST ANGLE METHOD
OF PROJECTIONS
X Y
VP
HP
PP
FV LSV
TV

FOR T.V.
FOR
S.V. FOR
F.V.
IN THIS METHOD,
THE OBJECT IS ASSUMED TO BE
SITUATED IN THIRD QUADRANT
( BELOW HP & BEHIND OF VP. )
PLANES BEING TRANSPERENT
AND INBETWEEN
OBSERVER & OBJECT.
ACTUAL PATTERN OF
PLANES & VIEWS
OF
THIRD ANGLE PROJECTIONS
X Y
TV
THIRD ANGLE
PROJECTION
LSV FV

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