INTRODUCTION TO DRAWING

ENGINEERING DRAWING

It is graphical representation of physical objects and their relationship.the ability to read drawing is the most important requirement of all technical people in engineering profession.

In the basic engineering drawing we mainly discuss about the geometrical drawing , it is the art of representation of objects on a drawing sheet and is the foundation of all engineering drawing...


NOTE: if a student understand the trick involved in it, he can easily gain the grip on the subject.
IMAGINATION is very important while studying engineering drawing.

click on the links below for the topics:

• BASICS
• SCALES
• CONIC SECTION
• PARABOLA
• Parabola by eccentricity
• parabola by triangle method
• parabola by oblong or rectangle method
• ELLIPSE
• ellipse by eccentricity
• ellipse by concentric circles method
• HYPERBOLA
• Hyperbola by eccentricity method
• rectangular hyperbola
• CYCLOIDS
• Cycloid and their construction
• Epi-cycloid
• Hypo-cycloid
• INVOLUTES
• ORTHOGRAPHIC PROJECTIONS
• ISOMETRIC PROJECTIONS

BASICS OF Engineering drawing

Creating a drawing
Drawing  instruments are used to draw straight lines ,circles , and curves accurately  concisely 

                   

The drawing tools are  like drawing board, mini drafter, instrument box containing compass,divider etc,.. set squares,protractor,french curves, drawing sheet,pencils,erasers..... 


DRAWING STANDARDS

• Drawing standards are set of rules that govern how the technical drawings are represented
• these are used so that every one can commonly understand the meaning of drawn picture

  Drawing sheet

we have many types and sizes of drawing sheets..  like A4,A3,A2,A1,A0 etc

while in the drawing sheet .. first we have to draw border lines and title box and then we have to start drawing

lettering

lettering and numbering should be in a perfect manner.. for example in this figure.. the upper and lower case letters  are neatly draw

    lines and its types 

basically lines which are used in the representation of the diagrams are of mainly 4 types they are

• Visible line : represent features that can be seen in the current view
• Dimension line ;Extension line;Leader line: indicate the sizes and location of features
• Hidden line : represent features that can not be seen in the current view
• Center line: represents symmetry, path of motion, centers of circles, axis of axisymmetrical parts

In this way we use different types of lines in the drawing

CYCLOIDS,EPICYCLOIDS ,HYPOCYCLOIDS

What is a Cycloid?

• A cycloid is a curve generated by a point on the circumference of the circle as the circle rolls along a straight line with out slipping..
• The moving circle is called the "Generating circle" and the straight line is called the "Directing line" or the "Base line".
• The point on the Generating circle which generates the curve is called the "Generating point"

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Construction of a Cycloid

EPICYCLOIDS

What is Epicycloid?

• The cycloid is called the epicycloid when the generating circle rolls along another circle outside(directing circle)

• The curve traced by a point on a circle which rolls on the out side of a circular base surface

CONSTRUCTION OF EPICYCLOID

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HYPOCYCLOIDS

construction of hypocycloid

• The curve traced by a point on a circle which rolls on the inside of a circular base surface.

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Applications of the cycloids

• cycloid curves are used in the design of the gear tooth profiles
• It is also used in the conveyor of mould boxes in the foundry shops.
• cycloidal curves are mainly used in Kinematics.