This document discusses the basic tools used for technical drawing and engineering graphics (EG). It describes commonly used drawing tools like pencils, drawing boards, T-squares, rulers, scales, compasses, and drafting machines. It also provides details on the different types of planes (perpendicular and oblique) and how they are projected, including examples of planes positioned perpendicular to and inclined from the horizontal and vertical planes.

1. Projection Of Planes
Created By:- Viraj shah

2. Basic tools For EG
Pens
Traditional and typical pens used for technical drawing
are pencils and technical pens.
Pencils in use are usually mechanical pencils with a standard lead
thickness. General line widths are 0.18 mm, 0.25 mm, 0.5 mm and
0.7 mm. Hardness varies usually from HB to 2H. Softer lead gives a better
contrast, but harder lead gives more accurate track.
 Drawing board
The drawing board is an essential tool. Paper will be attached and
kept straight and still, so that the drawing can be done with accuracy.
Generally, different kind of assistance rulers are used in drawing. The
drawing board is usually mounted to a floor pedestal in which the board
turns to a different position, and also its height can be adjustable. Smaller
drawing boards are produced for table-top use. In the 18th and 19th
centuries, drawing paper was dampened and then its edges glued to the
drawing board. After drying the paper would be flat and smooth. The
completed drawing was cut free. Paper could also be secured to the
drawing board with pins. More recent practice is to use self-adhesive tape
to secure paper to the board.

4. •T-square
A T-square is a straightedge which uses the edge of the drawing board as a
support. It is used with the drafting board to draw horizontal lines and to align other
drawing instruments. Wood, metal, or plastic triangles with 30 and 60 degree angles
or with two 45 degree angles are used to speed drawing of lines at these commonly
used angles. Also in use are a continuously adjustable 0-90 degrees protractor. An
alternative to the T-square is the parallel bar which is permanently attached to the
drawing board. It has a set of cables and pulleys to allow it to be positioned anywhere
on the drawing surface while stil remaining parallel to the bottom of the board. The
drafting machine replaces the T-square and triangles.
•Drafting machine
A drafting machine is a device which is mounted to the drawing board. It has
rulers whose angles can be precisely adjusted with a controlling mechanism. There
are two main types of apparatus: an arm-type parallelogram apparatus based on a
hinged arm; and a track-type apparatus which moves on a rail mounted to the top of
the drawing board. The accuracy of the arm type apparatus is better in the middle of
the board, decreasing towards the edges, whereas a track machine has a constant
accuracy over the whole board. The drawing head of a track-type drafting machine
slides on bearings in a vertical rail, which in turn is moved along a horizontal, top-mounted
rail. Both apparatus types have an adjustable drawing-head with rules
attached to a protractor scale so that the angle of the rules may be adjusted.

6. Rulers
Rulers used in technical drawing are usually made of polystyrene. Rulers come in
two types according to the design of their edge. Straight edge can be used with lead
and felt pens, whereas when technical pen is used the edge must be grooved to
prevent the spread of the ink.
 An architect's scale
Architect's scale is a scaled, three-edged ruler which has six different scales
marked to its sides. A typical combination for buildings details is 1:20, 1:50, 1:100,
1:25, 1:75 and 1:125. There are their own rulers for zoning work as well as for inch
units. Today scale rulers are made of plastic, formerly of hardwood. A pocket-sized
version is also available, with scales printed on flexible plastic stripes.
View of a drafting table: the old way of producing architectural and engineering
drawings. On the top of the board is a paraller ruler
Compass
The compass is used for drawing circles or arc segments of circles. One form has
two straight legs joined by a hinge; one leg has a sharp pivot point and the other has
a holder for a technical pen or pencil. Another form, the beam compass, has the pivot
point and pen holder joined by a bar, useful when drawing very large radius arcs.
Often a circle template is used instead of a compass when predefined circle sizes are
required.

8. INTRODUCTION
A plane is a two dimensional object having length
and breadth only. Its thickness is always neglected;
various shapes of plane figures are considered
such as square, rectangle, circle, pentagon,
hexagon, etc.

9. PROJECTION OF PLANES

10. Some of the
planar projection
are illustrated
here

11. A Plane is a two dimensional entity having only length
and breadth with negligible thickness which is
considered as zero.
TYPES OF PLANES
Planes may be divided as two main types. They are
(I) Perpendicular Planes
(II) Oblique Planes.
Perpendicular Planes
Planes which are perpendicular to any one of the
principal planes of projection are called as
perpendicular planes. These planes may be inclined or
parallel to the other principal plane.

12. Various positions of
perpendicular planes
(a) Planes perpendicular to V.P. And Parallel to H.P.
Consider a plane perpendicular to V.P. And Parallel to H.P. The top
view reveals the true shape of the plane
the front view is a line parallel to xy line.

13. (b) Planes perpendicular to H.P. And Parallel to V.P.
Consider a plane perpendicular to H.P. And Parallel to V.P.
The front view shows the exact shape and size of the plane.
The top view is a line parallel to xy line

14. (c) Plane perpendicular to both H.P. And V.P.
Consider a plane in space which is perpendicular to
both the H.P & V.P.
Both the front view and top view of the plane appear
as a straight lines on a single projector.

15. (d) Plane perpendicular to V.P. And inclined to H.P.
Consider a plane perpendicular to V.P. And inclined at an
angle to the H.P. The top view is shorter than its ture size.
The front view is a line inclined at an angle to xy line .

16. (e) Plane perpendicular to H.P. And inclined to V.P.
Consider a plane perpendicular to the H.P. And inclined at
an angle to the V.P. The front view is shorter than its true
size.
The top view is a line inclined at an angle to xy line.

17. (f) Surface of the plane kept inclined to HP and
VP or OBLIQUE PLANE
Consider the plane to be inclined to both the surfaces
that is the Horizontal plane and the Vertical plane

18. Example
A plate having a shape of an isosceles
triangle has base 50mm and altitude
70mm. It is so placed that in the front
view it seen as an equilateral triangle of
50mm side and one side is inclined at 45
deg to xy .

19. SOLUTION
Front view is seen as an equilateral triangle of 50mm side and one side is
inclined at 45 deg to xy
isosceles triangle has base 50mm and altitude 70mm.
Projections of Planes Peculiar problem wherein plane surface is inclined to
both the planes
Draw the side view and rotate the side view to get the true inclinations with
VP and HP as well as the top view.
Don’t forget to denote the points with appropriate notations

21. Thank you