ENGINEERING GRAPHICS By R.Nathan Assistant Professor Department of Mechanical Engineering

1
ENGINEERING GRAPHICSBy R.NathanAssistant
ProfessorDepartment of Mechanical Engineering
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
2
UNIT 2PROJECTION OF PLANES

• Engineering Graphics Lecture Notes

C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
3

• Engineering Graphics
  Lecture Notes

TYPES OF PLANE FIGURES
TRIANGLE
SQUARE
RECTANGLE
CIRCLE
TRAPEZOID
PARALLELOGRAM
PENTAGON
HEXAGON
DIAMOND
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• Engineering Graphics
  Lecture Notes

TYPES OF PLANES
PERPENDICULAR PLANES Planes which are
perpendicular to one of the principal planes of
projection and inclined or parallel to the other
OBLIQUE PLANES Planes inclined to both the
reference planes
TRACE OF PLANE
HORIZONTAL TRACE The intecsection line of the
plane surface with H.P
VERTICAL TRACE The intecsection line of the plane
surface with V.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
5

• Engineering Graphics
  Lecture Notes

PROJECTION OF PLANE PERPENDICULAR TO V.P AND
PARALLEL TO H.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
6

• Engineering Graphics
  Lecture Notes

EXAMPLE- An equilateral triangle ABC of 50 mm
side has its plane parallel to H.P and side AB
parallel to V.P Draw its projections when the
corner C is 15 mm from H.P and 45 mm from the V.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
7

• Engineering Graphics
  Lecture Notes

PROJECTION OF PLANE PERPENDICULAR TO H.P AND
PARALLEL TO V.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
8

• Engineering Graphics
  Lecture Notes

EXAMPLE- An equilateral triangle ABC of 50 mm
side is parallel to and 15 mm in front of V.P,
its base AB is parallel to and 75 mm above H.P,
Draw the projections of the triangle when the
corner is near the H.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
9

• Engineering Graphics
  Lecture Notes

PROJECTION OF PLANE PERPENDICULAR TO BOTH H.P
AND V.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
10

• Engineering Graphics
  Lecture Notes

EXAMPLE- A semicircle of diameter, CD 50 is
kept in the 1st quadrant such that its diameter
is perpendicular to V.P and H.P, Draw its
projections, when the diameter is near V.P,
distance of diameter from H.P is 15 mm and from
V.P is 20
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
11

• Engineering Graphics
  Lecture Notes

PROJECTION OF PLANE PERPENDICULAR TO V.P AND
INCLINED TO H.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
12

• Engineering Graphics
  Lecture Notes

EXAMPLE- A thin horizontal plate of 15 mm sides
is inclined at 45 to the H.P and perpendicular
to V.P, two of its parallel edges is parallel to
V.P, the plate is 10 mm above H.P and 15 mm
infront of V.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
13

• Engineering Graphics
  Lecture Notes

PROJECTION OF PLANE PERPENDICULAR TO H.P AND
INCLINED TO V.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
14

• Engineering Graphics
  Lecture Notes

EXAMPLE- Draw the projections of a circular
lamina of 30 mm diameter. The lamina is inclined
a an angle of 45 to V.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
15

• Engineering Graphics
  Lecture Notes

PROJECTION OF OBLIQUE PLANES
When the plane is inclined to both the reference
planes, its projections are drawn in three
stages First stage, the plane is assumed to be
parallel to H.P Second stage, it is tilted so as
to make the required angle with the H.P, its
Front View in this position will be a line while
its Top View will be smaller is size Third
stage, the plane is turned to the required
inclination with the V.P, only the position of
the Top View will alter. Its shape and size will
not be affected
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012
16

• Engineering Graphics
  Lecture Notes

EXAMPLE- Draw the projections of a regular
hexagon of 20 mm side, having one of its sides in
the H.P and inclined at 45 to the V.P and its
surface making an angle of 30 with the H.P
C.R.ENGINEERING COLLEGE Alagarkovil, Madurai -
625301
I - SEMESTER
04.10.2012