The document discusses orthographic projections and sectional orthographic projections. It explains that orthographic projections create 2D representations of 3D objects by projecting lines from edges orthogonal to the projection plane. There are two types of projections: first angle and third angle. The difference between them is the positioning of top, bottom, and side views. Sectional views indicate hollow and solid areas using hatching lines at 45 degrees spaced 0.25 mm apart. The document provides examples of orthographic and sectional orthographic projections of various machine parts.

1. Topic :
Guided By :
Branch : Batch :

2. Name ENROLLMENT NO.
Abhishek Chokshi 140120109005
Himal Desai
Harsh Dedakia
140120109008
140120109012

3. Orthographic
Projections

4. Basically, orthographic projection
means a 2-dimensional representation
of and 3-dimensional solid object. The
object is represented by projecting
lines from its edges such that the lines
are orthogonal to the projection plane.

5. Basically, there are 2 types of
orthographic projection. They are:
1) 1st angle projection
And
2)3rd angle projection
They are explained below.

6. PROJECTION SYSTEMS
1. First angle system
2. Third angle system
First Quadrant
Third
Quadrant

7.  The one and only difference between 1st
angle & 3rd angle projection is that only the
representation positions of plan (top view),
bottom view and side view.
 In 1st angle projection, the front view is in
center, top view is below front view, bottom
view is above front view, RHSV(right hand
side view) is to the left of front view and
LHSV(left hand side view) is to the right of
front view.

8. ORTHOGRAPHIC PROJECTION
1st angle system 3rd angle system

9. ORTHOGRAPHIC VIEWS
1st angle system 3rd angle system
Folding
line
Folding
line
Folding
line
Folding
line

10. ORTHOGRAPHIC VIEWS
1st angle system 3rd angle system
Front View
Front View
Right Side View
Right Side View
Top View
Top View

11. First angle
system
Third angle
system
PROJECTION SYMBOLS

12. 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.

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

14. 30
10
25 SQ
15 SQ
Ø30,Depth 10
40 SQ
ISOMETRIC
ORTHO. VIEWS

15. 25 Sq
4015
453535
15 Sq
40 Sq
Ø30
5
10
30
10
5
10
R.H.
S.V.
F.V.
T.V.

16.  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 :-

17. ISOMETRIC
VIEW Ø40
Ø64
24
50

18. L.H.S.VFRONT VIEW
TOP VIEW
1414
48
70
24
10
Ø40
50
Ø64
30
140

19. Sectional
Orthographic
Projection

20.  Sectional view is used to indicate that when
the solid is cut from a particular plane, where
there is mass and where it is hollow.
 Straight lines at 45 degree angle are drawn at
distance of 0.25 mm to indicate the mass and
the part that is hollow is kept plain
 Also, in sectional view, no hidden lines are to
be indicated.

21. Aim:-Sketch-1, shows Isometric View of a
machine part. Draw its following
orthographic views using third angle
method of projections, giving
dimensions.
(1) Sectional F.V.-AA
(2) T.V.
(3) L.H.S.V
A
A
8
Φ20Φ36
A
A
LEFT HAND SIDE VIEW SECTIONAL FRONT VIEW AA
TOP VIEW
X
SCALE:- 1:1
SYMBOL OF PROJECTION METHOD, NOT SHOWN
Sketch-1
2 HOLES,Φ 14
Φ36
Φ20
R35
65
14`
100
AA
SOLUTION`
30

22. A
A
LEFT HAND SIDE VIEW SECTIONAL FRONT VIEW AA
TOP VIEW
SCALE:- 1:1
SYMBOL OF PROJECTION METHOD, NOT SHOWN
SOLUTION`
AA
100
8
Φ20Φ36
2 HOLES,Φ 14
X
Φ36
Φ20
R35
A
A
Aim:-Sketch-1, shows Isometric View of a
machine part. Draw its following
orthographic views using third angle
method of projections, giving dimensions.
(1) Sectional F.V.-AA
(2) T.V.
(3) L.H.S.V
14
30
Hatch (section) lines, to be kept at 1 to 1.5 mm apart,
at 45° normally, but depends on areas to be hatched.

23. 50
10
40,DEPTH 24
60

25. Ø64
30
140
24
Ø40
50
10
L.H.S.VFRONT VIEW
1414
4870
TOP VIEW