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Lesson
1: Drawing the Base Bracket in Ortho and Ortho/Iso |
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Engineering Drafting is explored by the use of
ACAD 2002. The above simple model and the following
3 models that follow are examples of 3rd Angle
Projection, which is the projection technique
used in the United States. Refer to page 94 and
95 of your text to understand 1st and 3rd Angle
Projection.
In these four lessons we will be involving the
fundamentals of orthographic views and the creation
of an Isometric representation of the model that
is being explored.
The above animation represents the model rotating
on an axis which displays the useful view or the
working view of the model.It is positioned in
perspective view not isometric view.
In Engineering Drafting you will understand
that creating a part using isometric and orthographic
representation means that the part can be measured,
the various aspects of the model can be measured
accurately.
The Base Bracket is a common part which has 2
mounting holes and 2 vertical slots where another
machine part can be anchored and adjusted by this
slot.
Connecting Your Learning
As you work your way through this lesson, you
should reflect on the following questions:
What is the function of a base bracket?
How is the front side and top views determined
in the base bracket?
What an isometric model is and its symmetry?
Why is it important that all useful views are
represented in orthographic's ?
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The State of Arizona has assembled
Drafting standards
to make sure that Instruction is thorough and well
thought out by the instructor. By clicking on the
hyperlink below will upload to your browser window
the entirety of these standards. The standards that
are addressed in this lesson are below the hyperlink.
1.0 USE BOARD DRAFTING EQUIPMENT,
INSTRUMENTS AND MEDIA.
2.0 DEMONSTRATE SKETCHING, LETTERING,
AND LINE SKILLS.
- 2.1 Demonstrate freehand sketching skills for
drafting applications.
- 2.2 Demonstrate lettering skills.
- 2.3 Demonstrate line work.
6.0 DEMONSTRATE GEOMETRIC CONSTRUCTIONS
- 6.1 Measure Geometric Constructions.
- 6.2 Develop Geometric Constructions.
8.0 APPLY BOARD DRAFTING SKILLS TO COMPUTER-AIDED
DESIGN/DRAFTING (CADD)
- 8.1 Demonstrate computer skills for a CADD system.
- 8.2 Create dimensional CADD entities.
- 8.3 Create 3 dimensional CADD drawings.
The State of Arizona has also assembled Math
standards and many of these apply directly
to the vocational subject area of Drafting.
Drafting is a very precise discipline and
the use of mathematics is integral to design
and manufacturing. Below are the math standards
that are involved in this lesson
1M-P1. Compare and contrast
the real number system and its various subsystems
with
regard to their structural characteristics
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PO 2. Compare subsets of
the real number system with regard to their
properties
(commutative, associative, distributive,
identity, inverse and closure properties)
1M-P2. Construct, interpret
and demonstrate meaning for real numbers and absolute
- PO 3. Solve real-world distance problems
using absolute value
- PO 4. Determine, among the solutions to
a real-world problem, which, if any, is reasonable
- PO 2. Define absolute value as the distance
from the origin
4M-P1. Interpret and draw three-dimensional
objects
- PO 1. Sketch prisms, pyramids, cones, cylinders
and spheres
- PO 2. Classify prisms, pyramids, cones,
cylinders and spheres by base shape and lateral
surface shape.
- PO 3. Recognize the three-dimensional figure
represented by a two-dimensional drawing.
- PO 5. Make a model of a three-dimensional
figure from a two-dimensional drawing and
make a two-dimensional representation of a
three-dimensional object (models and representations
include scale drawings, perspective drawings,
blueprints or computer simulations)
4M-P4. Deduce properties
of, and relationships between, figures from
given
assumptions
- PO 1. Find similarities and differences
among geometric shapes and designs using a
given attribute (e.g., height, area, perimeter,
diagonals and angle measurements)
- PO 2. Identify arcs, chords, tangents and
secants of a circle
- PO 3. State valid conclusions using given
geometric definitions, postulates and theorems
- PO 4. Represent pi as the ratio of circumference
to diameter
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Lesson
Objectives
By the end of this lesson you should
be able to:
1. Draw the orthographic views and
dimension according to ASME14.5 using ACAD 2002.
2. Identify the isometric angles used to create
isometric views (30, 90 and 150 degrees)
3. Understand how to use the commands of : line,
copy, move, the @ command and vectoring,
4. Draw an Isometric view from orthographic views.
5. Center orthographic models in paper space using
1.5" between views.
6. Identify the working view of a model and its
front, top and side views.
Key
Terms
"click
on the key on any of these terms and it will hyperlink
to the course glossary" |
The
first model you will be drawing is called the base
bracket and below is enough of a dimensioned model
to draw the orthographic views. With the information
below you will draw in ACAD 2002 the 3 useful views
of the following model in full scale. Please Insert
Media Disk Engineering 3145 Lesson 1 into the D
drive of your computer if you have this course on
the Internet, otherwise ask your Instructor what
server to access this lesson file..
*Note:
The Lessons are best viewed with real player and you
can download the latest version by clicking on the
words real
player.
The following is what your completed
orthographic's of the Base Bracket should look like
before submission.
The
following screen capture shows half scale orthographic's
and a full scale Isometric of the Base Bracket.
This picture is an example of what your completed
assignment should look in drawing space.
*Note:
The Lessons are best viewed with real player and you
can download the latest version by clicking on the words
real
player.
After completing each
lesson attach your drawing to an email and send to
your Instructor:losimilar@yahoo.com
or if you are taking this course in the classroom
Print your assignment and pass it in to be graded.
Your
Text Book and Reading Assignments
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Text:
Engineering Drawing
and Design by
Jensen and Helsel
Use
this text as a reference together with the media
disks that you are using for the Semester. If
you are a classroom student media is available
on either of 3 Servers.
Lesson 1 assessment comprises:
-
Lesson 1a submitted as a dwg
file (10 pts.)
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Lesson 1b submitted as a dwg
file.(10 pts.)
Rubrics for Grading:
The drafting standards for assessing the quality and
accuracy of your drawings are as follows: Neatness,
Accuracy and Lines and Lettering. One half of one
point (.5) will be taking off your score in relation
to NALL.
Submit by email attachment
all of the above lessons as dwg. files and send to
your Instructor whose mail address is. losimilar@yahoo.com
Your Instructor will
grade your drawings within 24 hours and email you
back the grade/assessment of your work. You should
take allot of pride in your work.
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