Lecture 13 - Cadkey 1
Fundamentals of Engineering – Honors – ENGR H191
Question of the Day
What is the origin of the phrase“The Whole Nine Yards”?
ANSWER: Meaning to give absolute maximum
effort when trying to win or achieve something
From the 2nd World War; the American B-17 aircraft guns used ammunition belts that were nine yards long
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Fundamentals of Engineering – Honors – ENGR H191
Topics For Today
Sections Views Why section views are needed Types of section views References
BTG Chapter 6
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Fundamentals of Engineering – Honors – ENGR H191
Section Views
Goals Recognize various kinds of section
views, make full and half section views.
Improve visualization of interior features.
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Fundamentals of Engineering – Honors – ENGR H191
Section views are used when important hidden details are in the interior of an object. These details appear as hidden lines in one of the orthographic principal views; therefore, their shapes are not very well described by pure orthographic projection.
Section Views
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Fundamentals of Engineering – Honors – ENGR H191
Types Of Section Views
Full sectionsHalf sectionsOffset sectionsRevolved sectionsRemoved sectionsBroken-out sections
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Fundamentals of Engineering – Honors – ENGR H191
Cutting Plane
Section views show how an object would look if a cutting plane (or saw) cut through the object and the material in front of the cutting plane was discarded
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Fundamentals of Engineering – Honors – ENGR H191
Section LinesSection lines (crosshatching) are used to show where the cutting plane passed through solid material
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Fundamentals of Engineering – Honors – ENGR H191
Full Section View
In a full section view, the cutting plane cuts across the entire objectNote that hidden lines become visible in a section view
Hidden Lines are Visible
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Fundamentals of Engineering – Honors – ENGR H191
Full Section View
Shows cutting plane in the top viewMakes a full section on the front view
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Fundamentals of Engineering – Honors – ENGR H191
Full Section View
Note how the cutting plane is drawn and how the crosshatching lines mark the surfaces of material cut by the cutting plane.
No hidden lines on the section view, if possible.
Note: Interior lines behind cutting plane became visible.
Visible lines omitted
Incorrect
Correct
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Fundamentals of Engineering – Honors – ENGR H191
Multiple Sectioned Views
SECTION A-A
AA
SECTION B-B
B
B
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Fundamentals of Engineering – Honors – ENGR H191
Half Section View
The cutting planes do not cut all the way through to the object. They cut only half way. They intersect at the centerline.
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Fundamentals of Engineering – Honors – ENGR H191
Half Section View
Half Section used mainly for symmetric objects
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Fundamentals of Engineering – Honors – ENGR H191
Revolved Sections
Revolved sections examples show the shape of an object’s cross-section superimposed on a longitudinal view
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Fundamentals of Engineering – Honors – ENGR H191
Removed Sections Removed
sections are like revolved sections but moved aside. Note how they are named.
A
A
Section A-A
C CSection C-C
B
B
Section B-B
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Fundamentals of Engineering – Honors – ENGR H191
Broken Out Sections
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Fundamentals of Engineering – Honors – ENGR H191
Offset Sections
Offset sections are used to show interior features that do not lie along a straight line
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Fundamentals of Engineering – Honors – ENGR H191
Offset Sections
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Fundamentals of Engineering – Honors – ENGR H191
Conventional Revolutions
Used to make section views clear and avoid confusionAssociated with objects that have holes, ribs, spokes, or lugs in any combination equally spaced in a circular fashionNot projected orthographically to section viewExamples to follow
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Fundamentals of Engineering – Honors – ENGR H191Conventional Hole Revolutions
Note no hidden lines
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Fundamentals of Engineering – Honors – ENGR H191
Conventional Rib Revolutions
Note: Ribs not crosshatched
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Fundamentals of Engineering – Honors – ENGR H191Conventional Spoke Revolution
Note: Spokes not crosshatched
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Fundamentals of Engineering – Honors – ENGR H191Holes and Ribs in Combination
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Fundamentals of Engineering – Honors – ENGR H191
Assignment
Dwg 25 – F18-A Complete section views Due at end of today’s lecture
Dwg 26 – SECT 1-N Sketch Section Views Due at beginning of next lecture