MEMB113

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MEMB113

• ENGINEERING GRAPHICS CAE
• 1 MANUAL DRAWING

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Contents

• Chapter 1 Introduction to Eng. Graphics
• C2 Introduction to Manual Drawing
• C3 Engineering geometry (Basic geometrical
  constructions)
• C4 Dimensioning
• C5 Multi-view drawing
• C6 Isometric drawing
• C7 Auxiliary drawing
• C8 Section drawing
• C9 Tolerance
• C10 Assembly detail drawings

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CHAPTER 1

• Introduction to Engineering Graphics

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Content
MEMB113 MANUAL DRAWING CHAPTER 1

• Overview
• Engineering design
• Engineering graphics
• Sketching

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What Why
MEMB113 MANUAL DRAWING CHAPTER 1

• What?
• To provide the big picture of what engineering
  design eng. graphics is all about
• To learn the importance of sketches and the
  techniques in engineering graphics
• Why?

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1.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 1

• Engineering graphics communication involves the
  use of visual material to convey technical ideas
  and problem solutions.
• Engineering or technical drawing one of the
  most widely used method.
• Definition of drawing
• A graphic representation of an idea, concept or
  an entity which actually or potentially exists in
  life.

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1.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 1

• Importance
• A way of communication between engineers at all
  stages of the design problem solving from
  initial ideas, design, analysis manufacturing.
• For Visualisation, Communication and Documentation

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1.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 1

• Types of drawing
• artistic
• technical
• Illustrations
• rendering

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1.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 1

• Examples of different drawing types

3-D computer model of the interior of an office
building
A dimensioned technical/mechanical drawing
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1.2 Engineering design
MEMB113 MANUAL DRAWING CHAPTER 1
Concurrent design process
Traditional engineering design sequence
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1.2 Engineering design
MEMB113 MANUAL DRAWING CHAPTER 1

• Engineering drawing in design process

Visualisation is the ability to mentally picture
things that do not exist
to see the problem possible solutions
Visualise
Sketches
Communication - the design solution should be
communicated to others without ambiguity
to record initial ideas
created from sketches used for analysis
Geometric model
Detail drawings
to record the precise data for production process
Documentation - permanent record of the solution
3D model
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1.3 Engineering graphics
MEMB113 MANUAL DRAWING CHAPTER 1

• Drawings are widely used in engineering
  applications manufacturing, design, structural,
  electrical, etc.
• Standards and conventions
• To ensure everybody using the same method
• Commonly used
• ANSI, ASME, ISO, JIS, MS, DIN, BS

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1.3 Engineering graphics
MEMB113 MANUAL DRAWING CHAPTER 1

• What will you learn
• Producing engineering drawings
• Interpreting engineering drawings
• Graphics theory, visualisation,
• standards, conventions,
• applications,etc.

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1.3 Engineering graphics
MEMB113 MANUAL DRAWING CHAPTER 1

• E.g. Anatomy of a technical drawing

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1.4 Sketching
MEMB113 MANUAL DRAWING CHAPTER 1

• 3 methods of creating technical drawings
• Freehand, mechanical digital
• Technical sketching is the process of producing
  a rough preliminary drawing representing the main
  features of a product or structure
• Normally done by freehand, generally less
  finished, less structured/ restricted, take
  less time to produce

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1.4 Sketching
MEMB113 MANUAL DRAWING CHAPTER 1

• Technical sketches
• Used extensively in the first stage of design
  process / visualisation
• An informal tool used by everyone involved in the
  design manufacture of a product

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1.4 Sketching
MEMB113 MANUAL DRAWING CHAPTER 1

• Sketching tool
• Paper
• Pencils
• Eraser
• Sketching technique e.g.
• Straight line sketch
• Circle arc
• Component (proportional sketch)
• Pictorial sketch

Mechanical
Sketched
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1.4 Sketching
MEMB113 MANUAL DRAWING CHAPTER 1

• Sketching straight line

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1.4 Sketching
MEMB113 MANUAL DRAWING CHAPTER 1

• Sketching circle

Sketching component (proportional)
Sketching circle
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1.4 Sketching
MEMB113 MANUAL DRAWING CHAPTER 1

• Multi-view and pictorial sketches

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1.5 Conclusion
MEMB113 MANUAL DRAWING CHAPTER 1
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End of Chapter 1

• Thank You

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CHAPTER 2

• Introduction to Manual Drawing

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Contents
MEMB113 MANUAL DRAWING CHAPTER 2

• Drawing tools
• Drawing sheets and layout
• Lettering
• Lines
• Scale
• Abbreviations

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What Why
MEMB113 MANUAL DRAWING CHAPTER 2
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2.1 Drawing tools
MEMB113 MANUAL DRAWING CHAPTER 2

• Tools and instruments that are used to produce
  technical drawing manually
• Some tools are essentials while others are
  optional
• Including
• The drawing board/table
• Drawing instruments
• Measuring instruments
• The set squares
• Pencils and erasers
• Instruments to aid the drawing of curves

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2.1 Drawing tools
MEMB113 MANUAL DRAWING CHAPTER 2

• These are used to place the paper for drawing
• The drawing table
• Normally A0 or A1 size
• Usually attached with Tee-square
• The drawing board
• Normally a flat wooden board with Tee square
• Size to suit the range of paper sizes (A0-A3)
• Drawing sheet is fixed to the board using clips
  or tape

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2.1 Drawing tools
MEMB113 MANUAL DRAWING CHAPTER 2

• Drawing instruments
• Include instruments to draw circles
• Compasses friction-joint spring bow
• Many sizes e.g.
• To draw small circles - up to 20mm radius
• To draw circles 5mm to 150mm radius

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2.1 Drawing tools
MEMB113 MANUAL DRAWING CHAPTER 2

• Measuring instruments
• E.g scale rule
• Set squares
• Several types
• 60o,30o set square
• 45o set square
• adjustable set square

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2.1 Drawing tools
MEMB113 MANUAL DRAWING CHAPTER 2

• Pencil and erasers
• 18 degrees of hardness
• from 9H very hard
• to 7B very soft
• normally it is recommended
• 2H or H for construction, dimension, extension,
  leader, center lines
• HB or B for lettering, visible lines
• Instruments to aid drawing curves
• French curves
• Flexible curve

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2.2 Drawing layout
MEMB113 MANUAL DRAWING CHAPTER 2

• Drawing sheets
• Usually based on 'A' series
• Drawing sheets material - paper, linen, plastic
  film
• Drawing sheet layout
• Sheet frames or border
• Usually 20mm for A0 A1, 10mm for others
• Title block or title frame
• Represents general information source for a
  drawing
• Usually at bottom right-hand corner

A0 1189x841 A1 841 x 594 A2 594 x 420 A3
420 X 297 A4 297 X 210 All in mm
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2.2 Drawing layout
MEMB113 MANUAL DRAWING CHAPTER 2
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2.3 Lettering
MEMB113 MANUAL DRAWING CHAPTER 2

• Text is an important part of a technical drawing.
  Not all info required on technical dwg can be
  communicate graphically such as dimensions.
• One method of creating text is by freehand
  lettering. The standard style for freehand
  lettering is single-stroke Gothic lettering.

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2.3 Lettering
MEMB113 MANUAL DRAWING CHAPTER 2

• Characteristic of good lettering
• Should be neat, not sloppy
• Should be uniform and consistent i.e. same
  height, proportion inclination use guidelines
• Should have proper spacing of letters and words
• Should not contain unnecessary frills

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2.3 Lettering
MEMB113 MANUAL DRAWING CHAPTER 2

• Characteristic of good lettering
• Should use capital letters except for standard
  abbreviation e.g. mm, kg
• Recommended minimum height 2.5mm
• Recommended height 5mm to 7mm
• Underlining of lettering should be avoided

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2.4 Lines
MEMB113 MANUAL DRAWING CHAPTER 2

• Different line types for different purposes - to
  ensure drawing to be read quickly accurately
• Types of lines and thickness of line
• Commonly used line types thickness

2H/H/ 0.3mm
B/2B/ 0.5mm
2H/H/ 0.3mm
2H/H/ 0.3mm
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2.4 Lines
MEMB113 MANUAL DRAWING CHAPTER 2
Standard line types used in technical drawing
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2.5 Scale
MEMB113 MANUAL DRAWING CHAPTER 2

• What does it mean?
• Scale used should always be stated on drawing
  important info that is usually written in the
  title block.
• 'do not scale' / 'not to scale / NTS the
  drawing is not drawn to a certain scale
• Recommended scale
• 11 for full size
• for greater than full size
• 21 for twice full size
• 101 for ten times full size
• for reduced size
• 12 for half full size
• 110 for tenth full size
• other common scale - 15, 120, 150, 1100,
  1500 etc.

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2.6 Abbreviations
MEMB113 MANUAL DRAWING CHAPTER 2
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2.7 Conclusion
MEMB113 MANUAL DRAWING CHAPTER 2
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End of Chapter 2

• Thank You

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CHAPTER 3

• Engineering geometry
• (Basic geometrical constructions)

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Contents
MEMB113 MANUAL DRAWING CHAPTER 3

• Overview
• Geometric element
• Basic geometrical constructions
• Bisect lines, angles, etc.
• Draw circles, hexagon, pentagon, etc.
• Draw arc tangents, etc.

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3.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 3

• Geometry provides the building blocks for the
  engineering design process.
• Engineering geometry is the basic geometric
  elements and forms used in engineering design.
• Coordinate system
• cartesian coordinate system
• polar coordinate system

Cartesian coordinate system
Polar coordinate system
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3.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 3

• Absolute coordinate Relative coordinate
• Right hand rule
• to determine positive direction of axis

Relative
Absolute
Right hand rule
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3.2 Geometric elements
MEMB113 MANUAL DRAWING CHAPTER 3

• Can be categorised as points, lines, surfaces,
  solids.
• Points, lines, circles and arcs are basic 2D
  geometric primitives.

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3.2 Geometric elements
MEMB113 MANUAL DRAWING CHAPTER 3

• Point - theoretical location that has neither
  width, height, nor depth. It describe an exact
  location in space. Represented as a small cross.
• Line - has length and direction, but not
  thickness. May be straight or curve or both.

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3.2 Geometric elements
MEMB113 MANUAL DRAWING CHAPTER 3

• Circle - is a single-curved-surface, all points
  of which are equidistant from one point, the
  center

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3.2 Geometric elements
MEMB113 MANUAL DRAWING CHAPTER 3
Major components of a circle
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3.3 Basic Geometrical construction
MEMB113 MANUAL DRAWING CHAPTER 3

• To develop the skill of
• Division of lines and angles
• Construction of tangents
• Blending of radii
• Accuracy is important, inaccuracy causes the
  constructions unusable

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3.3 Basic Geometrical construction
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing a point
• Drawing a straight line
• Drawing a circle
• Drawing an arc

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Bisecting a straight line
• To divide a line into two equal parts

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing a perpendicular line from a point in a
  line
• AB is the line, and C is the point on it
• With center C and any radius, describe equal arcs
  to cut AB at E and F
• From E and F describe equal arcs to intersect at
  D
• Join C and D to give the required perpendicular

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Bisecting an angle
• ABC is the given angle
• From B describe an arc to cut AB and BC at E and
  D respectively
• With centers E and D, draw equal arcs to
  intersect at F
• Join BF, the required bisector of the angle

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing a line parallel to a given line at a
  given distance from it
• AB is the given line, and c is the given distance
• From any two points well apart of AB, draw two
  arcs of radius equal to c
• Draw a line tangential to the two arcs to give
  the required line

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• To construct a regular pentagon on a given line
• AB is the given line
• Bisect AB at C, erect a perpendicular at B, and
  mark off BD equal to AB
• With C as center and radius CD, describe an arc
  to intersect AB produced at E
• From A and B, and with radius AE, describe arcs
  to intersect at F
• With radius AB and centers A, B and F describe
  arcs to intersect at G and H
• Join FG, GA, FH and HB to complete the pentagon

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3
Constructing a pentagon, given the
diameter/radius of the circumscribe circle
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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• To construct a regular hexagon on a given line
• AB is the given line
• From A and B, and with radius AB, draw two equal
  arcs to intersect at O
• With radius OA or OB and center O draw a circle
• From A or B, using the same radius, step off arcs
  around the circle at C, D, E and F
• Join these points to complete the hexagon

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3
Constructing a hexagon, given the distance
across flats
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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Draw tangent from a point to a circle
• draw straight line from centre point A of the
  circle to the given point B
• find the midpoint O of the line AB
• set the compass to the radius AO
• draw a circle or arc intersecting the circle A
• the crossing point is the tangent point

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing a tangent to two given circles
• A and B are the centers of two given circles of
  radii r and R respectively
• With center B and radius R-r, describe a circle
• Bisect AB at X, and draw a semicircle on AB to
  cut circle R-r at C
• Join BC, and produce it to cut the larger circle
  at D
• Draw AE parallel to BD
• Join ED to give the required tangent

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing an arc tangential to two straight lines
• AB and CB are the given lines, and c is the
  radius of the required arc
• Draw two lines parallel to the given lines at a
  distance c from them to intersect at D
• With centers D and radius c, draw an arc, which
  will be tangential to both given lines

• - Erect perpendiculars at D to intersect AB and
  BC at E and F respectively. These are the points
  of tangency of the lines with the arc

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing an arc tangential to two arcs
  (externally)
• A and B are the centers of the given arcs of
  radii a and b respectively c is the external arc
  radius
• From centers A and B, describe two arcs of radii
  a c and bc respectively to intersect at C
• With center C and radius c, describe an arc which
  will be tangential to the given arcs
• E and F are the points of tangency of the three
  arcs

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing an arc tangential to two arcs
  (internally)
• A and B are the centers of the given arcs of
  radii a and b respectively c is the required
  tangential arc radius
• From centers A and B, describe two arcs of radii
  c-a and c-b respectively to intersect at C
• With center C and radius c, describe an arc which
  will be tangential to the given arcs
• E and F are the points of tangency of the three
  arcs

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing an arc tangential to a line and another
  arc
• A is the center of the given arc of radius a. BC
  is the given line, and b is the radius of the
  required arc
• From A, describe an arc with radius ab
• Draw a line parallel to BC and distant b, from it
  to intersect the arc ab at D
• From D, describe an arc of radius b, which will
  be tangential to the given line BC and the given
  arc a
• E and F are the points of tangency

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3.3 Geometrical constructions
MEMB113 MANUAL DRAWING CHAPTER 3

• Drawing an arc tangential to two arcs and
  enclosing one of them
• A and B as centers of two arcs of radius a and b
  respectively. Line c is the radius of the
  required arc
• With A and B as centers, describe arcs of radii
  ac and c-b respectively to intersect at C
• With center C and radius c, describe the required
  arc
• Join AC to intersect the curve at E, and produce
  CE to intersect the curve at F. Then E and F are
  the points of tangency of the three arcs

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End of Chapter 3

• Thank You

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CHAPTER 4

• Dimensioning

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Content

• Overview
• Terminology
• Basic Concept
• Standard Practice
• Detail Dimensioning
• Dimensioning Technique

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4.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 4

• Dimension is a way of displaying the size
  information and feature location on a drawing
• Generally consist of lines and number
• dimension lines
• extension lines
• leader lines
• number to indicate the measurement

Dimension
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Dimension line
Extension line
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R6
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4.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 4

• Proper dimensioning should give enough
  information to manufacture the component
• The dimension should not be redundant / over
  dimension

Example of redundant dimensioning
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4.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 4

• Designs are dimensioned based on two criteria
• Basic sizes and locations of features
• Details for construction and for manufacturing
• The unit of measurement should be consistent mm
  or inches
• ALL DIMENSIONS IN MM
• - should be written on drawing

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4.1 Overview
MEMB113 MANUAL DRAWING CHAPTER 4

• Generally two types
• Linear dimension in mm
• Angular dimension in degree, minutes and seconds

Linear dimension
Angular dimension
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4.2 Terminology
MEMB113 MANUAL DRAWING CHAPTER 4
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4.3 Basic concept
MEMB113 MANUAL DRAWING CHAPTER 4

• Size dimension
• May be the overall width of a part or the
  diameter of a hole
• Location dimension
• May be the length from the edge of an object to
  the center of a feature

Size and location dimensions are used to
describe parts for manufacture
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4.3 Basic concept
MEMB113 MANUAL DRAWING CHAPTER 4

• Basic criteria
• What info necessary to manufacture or construct
  the object?
• E.g. to drill a hole, need to know
• The diameter of the hole
• The location of the center
• The depth of the hole

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4.3 Basic concept
MEMB113 MANUAL DRAWING CHAPTER 4
Dimensions showing the location and orientation
of features, such as the location of the center
of the hole
Dimensions showing the size of features, such as
the height and depth of the part and the
diameter of the hole
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Dimension
• the numerical value that defines the size, shape,
  location, etc. of a feature.
• Normally height 3mm and space between line
  1.5mm

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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Dimension line
• A thin solid line that shows the extent
  direction
• Broken for the placing numbers
• Placement
• Dimension placement depends on the space
  available
• Should follow the standard practices

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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4
EITHER OR
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Reading direction
• All dimensions and note text must be orientated
  to read from the bottom of the drawing

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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Arrows
• Symbols at end of dim. Lines to show limits of
  the dim.
• Uniform in size style, usually 3mm long 1/3
  as wide
• Extension line
• A thin solid line perpendicular to dim. line,
  indicating which feature is associated with dim.
• Visible gap
• There should be visible gap of 1mm between
  feature and extension line

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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Leader line
• - A thin solid line to indicate the feature with
  which a dimension, note or symbol is associated
• Diameter symbol
• Radius symbol
• Tolerance

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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Spacing
• The minimum distance from the object to first
  dim. is 10mm
• Min. spacing between dimensions is 6mm
• Should be visible gap between extension line and
  the feature it refers
• Extend beyond dimension lines 2mm

Minimum dimension line spacing
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Grouping and staggering
• Dimensions should be grouped for uniform
  appearance
• Do not use object lines as part of your
  dimensions

Group dimensions
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Extension line
• Used to relate a dim. to one or more feature, and
  usually drawn perpendicular to feature dim.
  line
• The center of a feature, such as a hole, is
  located by making the center lines extension
  lines for the dimension. Extension lines can also
  cross to mark a theoretical point

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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Extension line should not cross dim lines, are
  not broken when crossing object or other
  extension lines, and are broken when crossing
  arrows

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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• View dimensioning
• Dimensions should be kept outside the object

Dimension outside the view
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Repetitive feature
• The symbol x is used to indicate the number of
  times a feature is to be repeated

Repetitive feature
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Staggered dimensioning

A part dimensioned using coordinate dimensions,
with a baseline or datum surface as a starting
point
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4
Stagger dimension text
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4.4 Standard practice
MEMB113 MANUAL DRAWING CHAPTER 4

• Others
• Avoid dimension to hidden lines
• The extension line can cross each other, but not
  dimension line
• The extension line can cross the object, but not
  the dimension line
• Avoid dimensioning inside of object
• Centre line cannot be used as dimension line, but
  can be extended as extension line

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4.5 Detail Dimensioning
MEMB113 MANUAL DRAWING CHAPTER 4
Dimensioning a blind hole
Dimensioning keyways keyseats
Dimensioning slots
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4.5 Detail Dimensioning
MEMB113 MANUAL DRAWING CHAPTER 4
Symbol for drilling operations
Dimensioning chamfers
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4.5 Detail Dimensioning
MEMB113 MANUAL DRAWING CHAPTER 4
Dimensioning arcs
Foreshortened leaders
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4.6 Dimensioning Technique
MEMB113 MANUAL DRAWING CHAPTER 4
Geometric breakdown technique
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MEMB113 MANUAL DRAWING CHAPTER 4
Example of the steps to create a dimensional
drawing
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MEMB113 MANUAL DRAWING CHAPTER 4
Summary of current and previous ASME standard
dimensioning ysmbol
Contour dimensioning
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End of Chapter 4

• Thank You