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Lesson
4: Drawing the Dovetail Finger in Ortho, Iso and 3d |
FIG. 4a (dovetail finger)
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In lesson 4 you will be drawing the dovetail finger.The
multi views of this part are the front, top an side
views. All of these views are necessary to describe
this part.
This dovetail finger has several hidden lines that
need to be identified, and can be located by projecting
lines from the other models. The "projection
rectangle" serves this purpose. This geometric
shape, which is a perfect square is developed while
drawing the other views. In the lessons media disc
you will be shown how to create this rectangle.
The word dovetail is used to describe an interlocking
joint in woodworking to lock corners of boxes and
cabinets. The finger part of the model lends its application
to a setup jig in assembly processes.
Connecting Your Learning
As you work your way through this lesson, you should
reflect on the following questions:
How did this part get its name?
How the name of an object often defines its shape?
Can you see how its shape could be used to hold an object
as well as allow another object to slide through its
angled surface?
How to create and use a "projection
rectangle"?
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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 of the
dovetail finger and dimension the model.
2. Identify the isometric angles used to create isometric
views (30, 90 and 150 degrees)
3. Scale down the orthographic view and create an Isometric
view.
4. Adjust the dimscale overall and linear to reflect
full scale dimensions in the ortho/iso drawing.
5. Create the 3d model of the dovetail finger from the
top orthographic view.
6. Working with colors for visualization enhancement.
7. Maintain approximate proportions using "boxing
in" also called the "Glass box Technique"
Key
Terms
"click
on the key on any of these terms and it will hyperlink
to the course glossary" |
The 4th model
you will be drawing is called the dovetail finger because
its function it is used to lock one part to another and
is used in assembly processes. This part could be made
out of allot of different materials including metals,
ceramics, plastics and wood.
Insert
your Lesson 4a media disk into your CD drive and begin listening
to the avi file: lesson 4a. You can open up both software
programs: ACAD and your media player at the same time and
toggle back and forth between screens, and be able to draw
and listen simultaneously. Below is an example of what your
completed drawing should look like. Pay attention to details
so you can obtain all your points for this assignment. It
is always better to get it right the first time, especially
when you have what the finished product should look like.
I will mention in the media files about the Dim-scale of
the dimension text.
The next part of Lesson 4 is creating the
Isometric view of these flat 2 dimensional images of the
v-block. This is where our talent begins to develop in conceptualizing
what this model really looks like. In this lesson you will
be scaling your orthographic views and adjusting the linear
dimscale accordingly. Common sense will say if a scale something
to half its size the dimension scale needs to be doubled.
I will explain this in the l esson disk titled Lesson 4b.
The following is what your completed assignment should look
like when completed.
Please Insert the Media Disk labeled Lesson
4 into your CD drive of your computer and begin listening
how to draw the 3d model of the Dovetail Finger. The lesson
avi is titled Lesson 4c and below is an example of a completed
accurate model of the Dovetail Finger. You will submit your
drawing in South East Isometric. This is what that Isometric
view and model looks like.
*Note:
The Lessons are best viewed with real player, or Windows
Media Player 9 for 2000 Professional
and Version 10 for XP.
After
completing each lesson attach your drawing to an email and
send to your Instructor's email.
email:
losimilar@yahoo.com
Your
Text Book and Reading Assignments
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Text:
Autocad Drafting by
Grout, Resetarits and James
Use
this text as a reference to the media disks that you
are using for the Semester.
Lesson 4 assessment comprises:
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Lesson 4a submitted as a dwg. file
(10 pts.)
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Lesson 4b submitted as a dwg. file.(10
pts.)
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Lesson 4c 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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