1. 16ME102 - ENGINEERING DRAWING
INTRODUCTION

2. CHAPTERS INTRODUCTION TO ENGINEERING DRAWING DRAWING STANDARDS
DRAWING SHEET
TRADITIONAL DRAWING TOOL
SCALES
LINES
LETTERING
PROJECTION
SECTIONING
DIMENSIONING

3. INTRODUCTION
An Engineering Drawing is a type of technical drawing, used to fully and clearly define requirements for engineered items, and is usually created in accordance with standardized conventions for layout, nomenclature interpretation, appearance size etc.

4. DRAWING STANDARD
Standard are the set of rules that govern how technical drawing are represented.
Drawing Standard are used so that drawing convey the same meaning to everyone who reads them.
Different countries use different standards according to there ease.
In India we follow IS (Indian Standard) which is some what like JIS system
IS: 1071 I Sizes of Drawing Sheet
IS: 9609 (Part 2) Lettering on Technical Drawing
IS: Scales on Drawing

6. JIS STANDARD PRACTICES

7. DRAWING
SHEET

8. DRAWING SHEET Sheet Size Margin Edge Line Border and Frame
Orientation Mark
Grid References
Title Block
Folding Sheet

9. Example of Drawing Sheet
Untrimmed Size
Trimmed Size
Example of Drawing Sheet
Margin
Orientation Mark
Grid Reference
Title Block
Margin Line
Border
Frame

10. SHEET SIZE
This section specifies sizes of blank and pre-printed drawing sheets for use with all technical drawings in any field of engineering. There are various standards for paper size such as A series, B series, C series.
Series A (ISO 216) is taken as standard all over the world
A0 size defined to have area of 1 square meter.
The length divided by the width is
Each subsequent size A(n) is defined as A(n-1) cut in half parallel to its shorter sides.
The area of B series sheets is the geometric mean of successive A series sheets. The international standard for envelopes is the C series of ISO 269.

11. Series A Paper Size (ISO 216)

12. MARGIN AND ORIENTATION OF PAPER

13. FOLDING OF DRAWING PRINTS
This section covers methods of folding of drawing prints.
All large prints of sizes higher than A4 are folded to A4 sizes.
The title blocks of all the folded prints appear in topmost position.
The bottom right corner shall be outermost visible section and shall have a width not less than 190 mm.
TYPES OF FOLD
Folding of prinits for Filing or Binding
Folding of prints for storing in Filing Cabinet

14. Folding of prinits for Filing or Binding

15. Folding of prints for storing in Filing Cabinet

17. TRADITIONAL DRAWING TOOLS
Drawing Table
Drawing Sheet
Drafting Tape
Pencil
Eraser
Sharpener
Drafter
Scale
Set-Square
T-Square
Compass

18. DRAWING TOOLS
Drawing Instruments or tools are used to prepare neat and accurate drawings.
To a greater extent, the ac-curacy of the Drawings depends on curacy of the Drawings depends on the quality of instruments used to prepare them.
The following is the list of Drawing Instruments and other materials required
Drawing Board Drafter (Drafting machine)
Set Squares
Protractor
Drawing Instrument Box
Drawing Sheet
Drawing Pencils
Drawing Pins/Clips

19. Drawing Board
Drawing board is made from strips of well seasoned soft wood generally 25 mm thick. It is cleated at the back by two battens to prevent warping.
One of the shorter edges of the rectangular board is pro One of the shorter edges of the rectangular board is pro-vided with perfectly straight ebony edge which is used as working edge on which the T edge on which the T-square is moved while making Drawings square is moved while making Drawing

20. PENCIL The difference is seen in the type of lead is in the pencil.
The hardness written as H, Black the mark the lead makes written as B.
The pencil No. 2(HB) pencil stands in middle.
The hardest lead in a pencil is a 9H pencil, the blackest lead is a 9B pencil.

21. TRY TO NAME THESE

22. SCALES

23. SCALES
Ratio of the linear dimension of an element of an object as represented in the original drawing to the real linear dimension of the same element of the object itself.
Full Size - A scale with the ratio 1: 1.
Enlargement Scale - A scale where the ratio is larger than 1 :1. It is said to be larger as its ratio increases.
Reduction Scale - A scale where ratio is smaller than 1: 1. It is said to be smaller as its ratio decreases.
SCALE 1 : 1 for full size
SCALE X : 1 for En-largement scale
SCALE 1 : X for Reduction scales

24. Scales for Use on Technical Drawings
In all cases, the selected scale shall be large enough to permit easy and clear interpretation of the information depicted.
Details that are too small for complete dimensioning in the main representation shall be shown adjacent to the main representation in a separate detail view (or section) which is drawn to a large scale.
The scale to be chosen for a drawing will depend upon the complexity of the object to be depicted and the purpose of the representation.

25. LINES

26. LINES PROPERTIES OF LINE
This section specifies the types of lines, their thickness and application for use in technical drawings.
Lines on an engineering drawing signify more than just the geometry of the object and it is important that the appropriate line type is used.
Line Thickness
Line Style
Precedence of line
PROPERTIES OF LINE

27. Line Thickness
Line Style

28. Precedence of line

29. TYPES OF LINE

31. LETTERING
Lettering used in engineering drawing is referred to as a Single Stroke, Commercial Gothic.
The height h of the capital letter is taken as the base of dimensioning
The lettering may be inclined 15’ to the right, or may be vertical
Lettering in Engineering Drawing
To communicate non graphic information
Thus must be written with-
Legibility
Shape
Space between words and letters
Uniformity
Size
Line Thickness

32. Use of Lettering

35. WORD SPACING

36. WORD SPACING General conclusion are:
Space between the letters depends on the countour of the letter at an adjacent side
Good Spacing creates approximately equal background are between letters.

38. SENTENCE SPACING
Leave space between the words equal to space required for writing a letter ‘O’

39. DIMENSIONING Providing information on a drawing about
Dimension as a numerical value expressed in appropriate units of measurement and indicated graphically on technical drawings with lines, symbols and notes.
Units of Measurement: The most commonly used unit for length is the millimeter. In civil engineering and architectural drawing, inch or foot is often used as a unit of length. Angles are shown in degrees.
Symbols are incorporated to indicate specific geometry wherever necessary.
Providing information on a drawing about
Distances (size or functional dimensions)
Sizes and positions (location or datum dimensions) of holes, grooves and other features.
Details relating to manufacture etc.

40. FUNCTIONAL DIMENSIONS (FDS)
CATOGRIES OF DIMENSIONING
FUNCTIONAL DIMENSIONS (FDS)
These are dimensions, which directly dictate the functioning of the component. That is a FD is a dimension defined on the basis of the function of the product and the method of locating it in any assembly of which it may form part of, e.g. the diameter of a shaft, the length of a bolt, etc.
NON FUNCTIONAL DIMENSIONS (NFDS)
These are dimensions, which do not directly affect the functioning of the component but have to be specified to enable production of that component, e.g. the size of a bolt head.
AUXILLARY DIMENSIONS (FDS)
These are dimensions which should not necessarily appear on the drawing but are sometimes included to avoid calculations or when they would provide additional/useful information. ADs are usually written in brackets.

41. DIMENSION TERMINOLOGY

42. LEADER LINES AND NOTES
Leader (or pointer) line – Thin continuous line connecting a note or dimension figure with the feature to which it applies. One end of the leader terminates in an arrowhead or dot.
The arrowhead touches the outline while the dot is placed within the object or on the outline
The other end of a leader is terminated in a horizontal line underlining the note

43. RULES FOR LEADER LINE
A leader line is never drawn horizontal, vertical or curved
It is drawn at an angle not less than 30o to the line that it touches
When pointing to a circle or arc, it is drawn radially

44. ARROWHEADS AND DIMENSION LINE POSITIONING
A dimension line is placed at least 6-8 mm away from an outline and from each other
An extension line extends ~3mm beyond a dimension line
Arrowhead – Placed at each end of a dimension line, its pointed end touches an outline, extension line or a centerline. It is also placed at the end of a leader line

45. SYMBOLS AND ABBREVIATIONS USED IN ENGG. DRAWING

46. TYPES OF DIMENSIONING Aligned Unidirectional
Dimension are aligned with the entity being measured.
They are placed perpendicular to the dimension line such that they may be read from the bottom or right-hand side of the drawing sheet.
Dimensions are placed at the middle and on top of the dimension lines.
Unidirectional
Dimensions are placed in such a way that they can be read from the bottom edge of the drawing sheet.
Dimensions are inserted by breaking the dimension lines at the middle.

47. PLACING DIMENSION METHOD FOR DIMENSIONING Parallel Dimensioning
Continues Dimensioning

48. PARALLEL (PROGRESSIVE) DIMENSIONING
All the dimensions are shown from a common reference line. Obviously, all these dimensions share a common extension line. This method is adopted when dimensions have to be established from a particular datum surface
Smaller dimensions should always be placed nearer the view. The next smaller dimension should be placed next and so on.

49. CHAIN (CONTINUOUS) DIMENSIONING
All the dimensions are aligned in such a way that an arrowhead of one dimension touches tip-to-tip the arrowhead of the adjacent dimension. The overall dimension is placed outside the other smaller dimensions

50. COMBINED DIMENSIONING
When both the methods, i.e., chain dimensioning and parallel dimensioning are used on the same drawing, the method of dimensioning is called combined dimensioning

51. CYLINDRICAL DIMENSIONS
Cylindrical features should be dimensioned by giving their diameters. They should be dimensioned in the views in which they appear as rectangles
CYLINDER – OUTER DIMENSION IS ALSO CIRCULAR. CAN BE HOLLOW OR SOLID

52. DIMENSIONING ARCS

53. DIMENSIONING CONICAL FEATURES
DIMENSIONING WRONG VS. CORRECT

54. General Hints on Dimensioning
NOTE that all “rules” on dimensioning are just guidelines. Use common sense depending on circumstances (i.e. there are no strict rules/regulations on dimensioning)
In metric system, all linear dimensions are considered to be in millimeters
Show full size dimensions regardless of the scale used in the drawing
Dimension any feature only once (i.e. no repetitions are allowed)
Dimension obviously identical features only once