Engineering Graphics- Basics Effectiveness of Graphics Language 1. Try to write a description of this object. 2. Test your written description by having someone attempt to make a sketch from your description. You can easily understand that
*1 The word languages are inadequate for describing the size, shape and features completely as well as concisely. Freehand drawing The lines are sketched without using instruments other than pencils and erasers.
Example Drawing by use of Instruments Instruments are used to draw straight lines, circles, and curves concisely and accurately. Thus, the drawings are usually made to scale. Example Drawing by use of Computer The drawings are usually made by commercial software
such as AutoCAD, solid works etc. Example Engineering Drawing *2 Elements of Engineering Drawing Engineering drawing are made up of graphics language
and word language. Graphics language Describe a shape (mainly). Word language Describe size, location and specification of the object.
Basic Knowledge for Drafting Word language Graphics language Line types Projection
method Geometric construction Lettering Drawing Standard *2
DEFINITION Standards are set of rules that govern how technical drawings are represented. Drawing standards are used so that drawings convey the same meaning to everyone who reads them. Standard Code Full name Country
Code USA ANSI American National Standard Institute Japan
JIS Japanese Industrial Standard UK BS British Standard Australia
AS Australian Standard Germany DIN Deutsches Institut fr Normung
ISO International Standards Organization Drawing Sheet Trimmed paper of a size A0 ~ A4. Standard sheet size (JIS) A4 A3
A2 A1 A0 210 x 297 297 x 420 420 x 594 594 x 841 841 x 1189 (Dimensions are in millimeters)
A4 A3 A2 A1 A0 Drawing Scales
Definition: Scale is define as ratio of linear dimensions of an element of an object represented in the original drawing to the linear dimension of the same element of the object by itself. Designation of a scale consists of the word SCALE followed by the indication of its ratio, as follow SCALE 1:1 for full size scales
SCALE X:1 for enlargement scales SCALE 1:X for reduction scales Basic Line Types Meaning of Lines Visible lines : represent features that can be seen in the current view Hidden lines : represent features that can not be seen in the current view Center line : represents symmetry, path of motion, centers
of circles, axis of symmetrical parts Dimension and Extension lines indicate the sizes and location of features on a drawing Example : Line conventions in engineering drawing Traditional Drawing Tools DRAWING TOOLS
*4 *3 1. T-Square 2. Triangles DRAWING TOOLS 2H or HB for thick line 4H for thin line
3. Adhesive Tape 4. Pencils DRAWING TOOLS 5. Sandpaper 6. Compass
DRAWING TOOLS 7. Pencil Eraser 8. Erasing Shield DRAWING TOOLS 9. Circle Template 10. Tissue paper
DRAWING TOOLS 11. Sharpener 12. Clean paper Lettering Lettering Standard ANSI Standard
This course Use a Gothic text style, Use only a vertical Gothic either inclined or vertical. text style.
Use all capital letters. Use both capital and lower-case letters. Use 3 mm for most Same. For letters in title text height.
block it is recommend to use 5~8 mm text height Space between lines N/A. of text is at least 1/3 Follows ANSI rule.
of text height. Stroke Sequence I L E H
T F Stroke Sequence V X W
N Y Stroke Sequence Z M K A
4 Stroke Sequence O Q C G
D R Stroke Sequence U P B J
1 2 Stroke Sequence 5 7 Stroke Sequence S
0 8 9 3 6
Stroke Sequence l i Stroke Sequence w x v z
k Stroke Sequence y f j r t
Stroke Sequence o a c b d e
p q Stroke Sequence n m g u
s h Example : Good and Poor Lettering GOOD Not uniform in style. Not uniform in height. Not uniformly vertical or inclined. Not uniform in thickness of stroke.
Area between letters not uniform. Area between words not uniform. Sentence Composition Leave the space between words equal to the space requires for writing a letter O. Example ALL O DIMENSIONS O ARE OIN MILLIMETERS O UNLESS
OTHERWISE O SPECIFIED. References- IMAGE 1. http://www.bibliocad.com/library/piston_63810 2. http://www.dreamstime.com/royalty-free-stock-photo-enginee ring-drawing-equipment-image19335615 3. http://trade.indiamart.com/details.mp?offer=4715409313 4. http://en.wikipedia.org/wiki/Set_square 5. http://nptel.ac.in/courses/112103019/3 6. http://grafoindia.com/drawinginstruments.html
http:// www.engineering108.com/pages/Engineering_graphics/Enginee ring_graphics_tutorials_free_download.html References- Contents http://www.engineering108.com/pages/Engin eering_graphics/Engineering_graphics_tutoria ls_free_download.html A text book of engineering graphics- Prof. P.J SHAH Engineering Drawing-N.D.Bhatt
Engineering Drawing-P.S.Gill Thank You
