orthographic projections of engg. graphics

TOPICS OF “ENGINEERING GRAPHICS”
(Mechanical Portion)
( C ) ORTHOGRAPHIC PROJECTIONS
FROM GIVEN ISOMETRIC VIEW
( D ) ISOMETRIC VIEW/PROJECTIONS
FROM GIVEN ORTHOGRPHIC VIEWS
Without Sections With Sections
View i.e. drawing Projections
Topic no. Topic Content No. of Lectures
07
05

TYPES OF LINES
USED IN
ENGINEERING
DRAWING
APPLICATIONS OF
LINES ON
DRAWING
G2
CUTTING PLANE
LINE (IN T.V)
CONTINUOUS
THICK
A
A
G1
CUTTING PLANE
LINE (IN F.V)
G1
B CONTINUOUS
THIN (WAVY)
B
C SHORT ZIGZAG
THIN
C
D
D
D CONTINUOUS
THIN
D
E
SHORT DASH
MEDIUM (DOTED
LINE )
E
F LONG CHAIN
THIN (CENTER
LINE)
F
 40
 30
25
150
 60

Trimmed and untrimmed drawing sheet
sizes are commercially designated as A0
(Maximum size), A1, A2, A3, A4 & A5 (Least
size).
In Engineering Graphics’ term work, all
the 4 sheets will be of A2 (approximately ½
Imperial) size
The following two systems are adopted for
dimensioning purposes on orthographic
views as well as on pictorial view.
Dimensioning Techniques

20
35
ALIGNED
SYSTEM
(FOR A2 TO A5
SHEET SIZE)
UNIDIRECTIONAL
SYSTEM
(FOR LARGE SIZED
SHEETS)
35
20
ARROW HEADS
(H x 3H) 3H
H

ORTHOGRAPHIC PREOJECTIONS
(MULTI VIEW REPRESENTATIONS i.e. F.V.,
T.V. & S.V. – L.H.S.V OR R.H.S.V) FROM
ISOMETRIC VIEW
 PLANES OF PROJECTIONS
 QUADRANTS
 VISION DIRECTIONS

 SCALING OF A DRAWING (Full Size 1:1,
Reduced 1:2 or Enlarged 5:1 )
 VIEWES
 METHODS OF PROJECTIONS WITH
THEIR SYMBOLS

(AS PER BUREAU OF INDIAN STANDARDS
FOR ENGINEERING DRAWING.)
SCALING OF A DRAWING
RECOMMENDED SCALES
1. FULL SCALE e.g. 1: 1
In certain cases the engineering components may
be very large or very small for drawing purposes,
hence the corresponding scale may be preferred
from the following

3. ENLARGED SCALE e.g. 50:1, 20:1, 10:1,
5:1, 2:1
2. REDUCED SCALE e.g. 1:2, 1:2.5, 1:5,
1:10, 1:20,
1:15, 1:100,
1:200, 1:500,
1:1000, 1:2000,
1:5000,
1:10000

SYMBOLS USED ON
ENGINEERING DRAWING SHEET
FIRST ANGLE METHOD
OF
ORTHOGRAPHIC
PROJECTIONS
THIRD ANGLE METHOD
OF
ORTHOGRAPHIC
PROJECTIONS
M/c. PARTS ARE NEVER ASSUMED IN SECOND
OR IN FOURTH QUADRANT, AS THE VIEWS
MAY OVERLAP ON ONE ANOTHER ABOVE XY
OR BELOW XY RESPECTIVELY.

HP
VP
PP
ISOMETRIC VIEW
OF
FIRST ANGLE METHOD OF PROJECTIONS (FOR L.H.S.V.)
Z1
X
Y
Y
X
OBJECT IN
FIRST
QUADRANT
(FOR L.H.S.V.)

Fig. 2(c) shows turning of the planes H.P & P.P
with their respective hinges, considering
V.P as fixed plane.
b) F.V is within L & H, T.V is within L & D,
While L.H.S.V is within H & D.
It may be noted that :-
(a) F.V. (X directional view) is on V.P, T.V. (Y
directional view) is on H.P, while L.H.S.V (Z1
directional view) is on P.P
c) The symbol for Ist angle method of projections
is placed as shown on fig. 2(c)

Fig. 2(c)
X Y
H.P
T.V.
L
V.P
F.V.
L.H.S.V.
D
P.P
H

AIM: Fig. 2(a) shows the Pictorial
(ISOMETRIC) view of a cut
block. Draw its following
orthographic views using Ist angle
method of projections.
I. Front View
II. Top View
III.R. H. S.View

X
Fig 2(b)
P.P
Z2
V.P
H.P
Z2
Fig 2(a)
X
Y
Y
Y

Note : Ist angle means, the block is assumed in
front of V.P, above H.P and inside P.P,
as in fig. 2(b) where the F.V. is
projected on V.P, seen in X direction,
T.V. is projected on H.P, seen in Y
direction & R.H.S.V. is projected on
P.P, seen in Z2 direction

a) F.V. (X directional view) is on V.P, T.V. (Y
directional view) is on H.P, while R.H.S.V (Z2
Fig. 2(c) shows turning of the planes H.P & P.P with
their respective hinges, considering plane V.P as
fixed plane.
b) F.V is within L & H, T.V is within L & D, While
R.H.S.V is within H & D.
c) The symbol for Ist angle method of projections is
placed as shown on fig. 2(c)

Fig. 2(c)
H.P
T.V.
L
F.V.
V.P
X Y
R.H.S.V.
D
P.
P
H

(ISOMETRIC) view of a cut block.
Draw its following orthographic views
using IIIrd angle method of projections.
I. Front View
II. Top View
III. Left Hand Side View

H.P
P.P
X
Y
Z1
X
Y
V.P
Fig 3(b)
Y
Z1
X
Fig 3(a)
Plane H.P turned
up(above V.P)
Plane P.P turned side
way(towards left side of
plane V.P)

Note : IIIrd angle means, the block is
assumed behind V.P, below H.P and
inside P.P, as in fig. 3(b) where the F.V.
is projected on V.P, seen in X direction,
T.V. is projected on H.P, seen in Y
direction & L.H.S.V. is projected on
P.P, seen in Z1 direction

c) The symbol for IIIrd angle method of projections
b) F.V is within L & H, T.V is within L & D, While
L.H.S.V is within H & D.
Fig. 3(c) shows turning of the planes H.P & P.P with
their respective hinges, considering plane V.P as
fixed plane.
directional view) is on H.P, while L.H.S.V (Z1

T.V.
4
D
6
L.H.S.V
2
F.V.
L
X Y
Fig.
3(c)

(ISOMETRIC) view of a cut block.
Draw its following orthographic
views using IIIrd angle method of
projections.
I. Front View
II. Top View
III.Right Hand Side View

X
Y
X
Y
H
P.P
Z2
Fig. 4(b)
Planes H.P, V.P & P.P are assumed as transparent
Y
Z2
Fig. 4(a)
X
H.
P
V.P

Note : IIIrd angle means, the block is assumed
behind V.P, below H.P and inside P.P, as
in fig. 4(b) where the F.V. is projected
on V.P, seen in X direction, T.V. is
projected on H.P, seen in Y direction &
R.H.S.V. is projected on P.P, seen in Z2
direction.

b) F.V is within L & H, T.V is within L & D,
While R.H.S.V is within H & D.
c) The symbol for IIIrd angle method of projections
Fig. 4(c) shows turning of the planes H.P &P.P with
their respective hinges, considering plane
V.P as fixed plane.
directional view) is on H.P, while R.H.S.V (Z2

Y
X
H
.
P
T.V. D
V
.
P
F.V.
L
Fig. 4(c)
P
.
P
R.H.S.V.
H

Step by step procedure
Suggested to prepare
Orthographic views (First angle
method) for The simple
component Shown pictorially in
figure

R40
20
100
80
ø40
80
20
TOP VIEW
FRONT VIEW
R.H.S.V
SCALE: 1:1
SYMBOL IS
NOT MARKED
20 20

FIGURE SHOWS ISOMETRIC VIEW OF A
SIMPLE OBJECT(WITHOUT DIMENSIONS)
SHOW ITS THREE ORTHOGRAPHIC VIEWS
Use First Angle
Method
1. Front View
2. Top View
3. L.H.S.View
A
B
a
b
3
c
2
1

F.V
T.V
L.H.S.V.
B
a
b
c
3
2
1
b
3
A

FIGURE SHOWS ISOMETRIC VIEW OF AN
OBJECT(WITHOUT DIMENSIONS) SHOW ITS
THREE ORTHO GRAPHIC VIEWS
Use Third
Angle Method
1. Front View
2. Top View
3. L.H.S.View
1. Front View
2. Top View
3. L.H.S.View
A
a
b
3 c
2
1

FRONT VIEW
L.H.S VIEW
TOP VIEW
A
a
b
3
c
2 1

Aim : Figure shows isometric
view, of a simple machine
component.
Draw its following Orthographic
views, & dimension them.
1. Front View
2. Top View
3. R.H.S. View
Use First Angle Method of projection

Figure, is the isometric view
X
Figure
L = 75+25=100
H = 10+30=40
D=50

10
10
F.V.
25 75
40
T.V.
ORTHOGRAPHIC
VIEWS
F.V L=100
H=40
T.V L=100
D=50
S.V D=50
H=40

30
10
25 SQ
15 SQ
Ø30,Depth 10
40 SQ
ISOMETRIC
ORTHO. VIEWS

25 Sq
40
15
45
35
35
15 Sq
40 Sq
Ø30
5
10
30
10
5
10
R.H.
S.V.
F.V.
T.V.

 Figure shows the isometric
view of a vertical shaft support.
 Draw its all the three views,
using first angle method of
projections.
 Give the necessary dimensions
as per aligned system.
Exercise :-

ISOMETRIC
VIEW Ø40
Ø64
24
50

14
14
48
70
24
10
Ø40
50
Ø64
30
140
L.H.S.V
FRONT VIEW
TOP VIEW

Isometric view of a rod support is
given.
Draw its all the three orthographic
views, using first angle method of
projections.
Give all the dimensions.
Exercise :-

TOP VIEW
R22
20
40
10
FRONT VIEW
RIGHT SIDE
VIEW
140
20
80
SCALE: 1:1
30
30
66
26
30

10
20
R20
R8
30
ISOMETRIC
ORTHO. VIEWS

45
30
8
20 25
16
R8
R20
30 20
10
100

SECTIONING OF A
MACHINE COMPONENT
BY ANY ONE SECTION
PLA NE ,OUT OF THREE
FOLLOWING MENTIONED
SECTION PLANES

(1)BY A VERTICAL SECTION PLANE
(PARALLEL TO PRINCIPLE V.P.)
Hence ,
(a)The real or true shape of the section is
observed in its F.V.
(b)Section plane will be seen as a cutting
plane line (similar to center line ,thick at
ends) with corresponding horizontal vision
direction arrows at the center of thick ends in
its T.V. & S.V.

(2)BY A HORIZONTAL SECTION PLANE
Hence,
(a)The real or true shape of the section is observed in
its T.V.
(b) The cutting or section plane will be observed as a
cutting plane line (similar to center line ,thick at
ends) with the corresponding vertically downward
vision direction arrows at the center of the thick
ends in its F.V. and in S.V.

(3) BY A SECTION PLANE , NORMAL TO
BOTH H.P. AND V.P.(i.e. parallel to
profile plane or side view plane)
Hence,
(a)The real or true shape of the section is observed in
its S.V.
(b) The cutting or section plane will be observed as a
cutting plane line (similar to center line ,thick at
ends) with the corresponding vertically downward
vision direction arrows at the center of the thick
ends in its F.V. and in T.V.

50
15
15
Figure shows isometric view of a
machine component. Draw its
(1)Front view, Top view & L.H.S
View, using 3rd angle method
of projections.
(2)Sectional Front view, Top
view & L.H.S.V., using 3rd
angle method of projections.

10
50 50
60
40
30
15
25
5
30
50
15
Front View
Top View
L.H.S.View
1.
Ortho. Views (No sectioning)

A
B
Retained split of the
machine parts
It will be nearer to V.P.
in 1st angle method &
against the vertical
plane in 3rd angle
method.

50 50
60
40
30
15
25
5
10
30
Top View
Sectional Front View -AB
L.H.S. View
A B
A
B
2.
(With sectioning)

20
20
60
A
A
X
Figure shows the pictorial
view of a machine component.
Draw its following views as
per First angle method of
projections
(1) Front view from X direction.
(2) Sectional top view-AA
(3) L.H.S. View

20
Sketch shows the assumed cut model (retained part of
the machine component / split against the observer) due
to horizontal section plane passing through AB.
X

120
60
28
Ø30, 7deep Ø20
20
20
14
F.V.
Sectional T.V.
L.H.S.V.
A A
A A

20
60
30
X
A
B
Figure shows the pictorial view
of a machine components.
Draw its following views,
using 3rd angle method of
projections.
(1) Front view from arrow X
(2) Top View
(3) Sectional R.H.S.V - AB

B
A
Retained split of the
machine parts
Retained split, will be
nearer to V.P. in 1st
angle method &
against the vertical
plane in 3rd angle
method.
No hatching in
this area as not
contained in the
section plane

80
20
20 20
60
90
40
A
A
A
F.V.
T.V.
SEC.
R.H.S.V

A
C
B
HALF SECTIONAL F.V.-AB HALF SECTIONAL
LEFT S.V.-BC
TOP VIEW

REMOVED & REVOLVED
SECTIONS
SPECIAL SECTIONS

REMOVEDSECTION
REVOLVED
SECTION
REMOVED
SECTION

orthographic projections of engg. graphics

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orthographic projections of engg. graphics