Brief Introduction Lecture:F16 Handout Page 1 Brief Introduction to Engineering Graphics The use of drawings to convey information. Sketching freehand straight edge CAD drawings 2D drafting 3D model to 2D drawings 1 Orthographics ◦ Multiviews Pictorials ◦ Isometric - a special type of axonometric which uses 120 degree angles for axis. ◦ Obliques-front faces similar to orthographic: 90° axis Perspectives ◦ Used in architecture, more realistic but hard to use for measuring. Isometric Oblique 120° 90° 2 Different Graphical Representation of objects. On pg 27: See Fig. 3 and Table 1
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Brief Introduction Lecture:F16 Handout Page 1
Brief Introduction
to Engineering GraphicsThe use of drawings to convey
information.
� Sketching
� freehand
� straight edge
� CAD drawings
� 2D drafting
� 3D model to 2D drawings
1
� Orthographics◦ Multiviews
� Pictorials
◦ Isometric - a special type
of axonometric which uses
120 degree angles for axis.
◦ Obliques-front faces similar
to orthographic: 90° axis
� Perspectives
◦ Used in architecture, more
realistic but hard to use for
measuring.
Isometric Oblique
120°
90°
2
Different Graphical Representation of objects.On pg 27:
See Fig. 3
and Table 1
Brief Introduction Lecture:F16 Handout Page 2
Engineering Lettering
� Information that is hard to read is even harder to understand…use
GOOD ENGINEERING LETTERING
� Class standard is VERTICAL and UPPERCASE (except in the case of
*metric units) as shown on pg. 39 Fig. 21of graphics text
� Usually height of text is about 1/8” (3 mm) but don’t measure it…use
guidelines if provided.
Example of lettering expected for
all class assignments.
Fractions can vary from standard…don’t make too small
3
*Note: 25.4 mm = 1 INCH
mm is millimeters, leave lowercase
10 mm = 1 centimeter
mm IS THE STANDARD METRIC UNIT
See pg. 30 Sec. 3 I inch
Examples of Lettering
Decent Lettering – spaced a
bit too close together
Same here – needs to keep letters VERTICAL!!!
FLOATING letters – needs to use
the guidelines
Incorrect fraction (too small).
POOR form (one shouldn’t
have top or bottom plus
NON-UNIFORM height.
Good Form plus correct way to do millimeters (case-sensitive)
4
Brief Introduction Lecture:F16 Handout Page 3
Expectations of LetteringGood – spacing of letterings could be improved upon
Fair to Poor – form is fine but not uniform height –FLOATING letters.
Poor to Fail – Not vertical, not uniform height, poor spacing.
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- Linetypes -
� The type or appearance of a line depends on what it
is trying to represent.
� Be familiar with the different types of lines found in
Fig. 7 on pg. 29.
Solid/Continuous indicates a
visible surface/edge
Dashed indicates a hidden
surface/edge
Centerline indicates symmetry
� Each linetype has its own lineweight too.
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Radius of:
Centermark indicates center of circular feature. Extends past actual diameter Ø
of circle of or radius of arc.
22 mm
Started at 10 mm mark - due to manufacture of ruler
Brief Introduction Lecture:F16 Handout Page 4
- RULES and EXPECTATIONS -
� Use of straight edge is allowed.
� Lettering templates, circle templates, compasses
and other “drafting” equipment is not allowed.
� NEATNESS and ACCURACY do count!
� Even Lineweight (LWT)
� Sharp corners
� Gaps (or no gaps) in important areas
� Examples will be given showing both “good” and
“poor” work.
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- SKETCHING EXAMPLES -
� FAIR (B work)• Uneven LW
• Visible Lines need to be darker
• Poor dashes
� GOOD (A
work)
� POOR (D
work)• overall
neatness
• used straightedge (sort of)
� I suggest using a SHARP No. 2 pencil or a 0.7 mm HB lead mechanical pencil.
� Don’t forget the straight edge.
� Fig. 24 on page 70 shows examples of good totally freehand lines. You are allowed and expected to use a straight edge.