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Full section
 Cutting plane passes throug entire object

Offset Section
Cutting plane bent at 90 degress to show more detail on asymmetrical objects

Half Section
  Removes a quarter of the object
  Reveals half of its internal details
  All hidden lines ommitted
  Not necessary to label cutting plane
  Only half of view is cross sectioned

Revolved Section
 Shows crosssection by rotating 90 degrees
 Remains on object

Removed Section
 Shows cross section by rotating 90 degrees
 Moved to the side of object

Broken out section
 No cutting plane required
 Does not modify rest of view

Broken View
 Used for extremely large or long objects
 2 break lines

Detailed View
Circle cut out showing more detail of an object
Must have scale

Sectioned Pictorials
Sketch of the object with portion missing

Do NOT Hatch!!!
 Ribs
 Thin parts like gaskets
 Shafts or pins
 Screws or nuts

Cast Iron and General Use
ANSI 31

Steel
 "striped"
 ANSI 32

Brass, Bronze, Copper
ANSI 33
"Road"

Lead, Zinc, Magnesium
ANSI 37


Crest
Peak or prominent point of a thread

Root
Bottom point at which sides of a thread meet

Flank
Thread surface that connects a crest and a root

Angle
Degrees between two flanks

Pitch
Distance between 2 adjacent crests or 2 adjacent roots

Thread length
Length of a threaded portion of a shaft


Shank
Unthreaded portion between head and threads

Thread symbols
Detailed, schematic, simplified

Knurl
Pattern cut into cylindrical parts to improve gripping




Counterdrilled
CDRILL or CD



What is the standard measurement of an engineers's scale?
Inches

What is the standard measurement of a metric scale?
Millimeter

How does an architect's scale work?
Number on left of equal sign is specified by some fraction of an inch, number on the right is ALWAYS 1'0"
Ex. 1/2 = 1'0"

Tolerance
Range of acceptable values for a particular dimension
The smaller the tolerance, the higher the cost of manufacturing

General Tolerance
Applies to all dimensions of a drawing
Often found in title block
Normally in bilateral form

Limit form  Tolerance
Has max value over min value

Unilateral form  Tolerances
Has base value, then to the right of it has the maximum added above mimimum added

Bilateral form  Tolerances
Base diameter, then to the right it has +/ a number

Linear Fit Tolerances
How tight or how loose moving and sliding parts wll fit

Hole tolerance
LPH  SPH
 Determines cost of hole

Shaft Tolerance
LPS  SPS
 Determines cost of shaft

Allowance
SPH  LPS
Tightest fit between two moving parts
Does not affect cost of parts

Maximum Clearance
LPH  SPS
Loosest fit between parts
Does not affect cost of parts

Clearance Fit
Shaft is always smaller than hole

Line fit
Shaft is either smaller or equal to hole

Transition fit
Shaft could be larger or smaller than hole
Cheapest way to manufacture part

Which fit is the cheapest to manufacture a part?
Transition fit

Interference fit
"Force fit"
shaft always larger than hole

Geometric tolerances
Controls level of error of shape not size

Dimensioning
Always in real world units
Do not put units by numbers

Styles for dimensioning
 Unidirectional: dimensions face same direction
 Alligned: dimensions parallel to lines

Dimension spacing
 First row: 3 letter heights away (3/8")
 Successive rows: 2 lettee heights away (1/4")

Dimensioning Cylinders
Place diameter where it appears at a rectangle

Bolt circle
When feature has repetitive holes in circular pattern
BC

Repetitive features
Ex. .75 DIA  4 HOLES

Horizontal projection plane
Top view
Depth and width

Frontal projection plane
Front view
Height and width

Profile projection plane
Side view
Height and depth

Which dimensions on an orthographic projection project directly?
Height and width

What is the difference between pictorials and orthographic projections?
Orthographic projections use 2D views to represent an object. Projection pictorials show all three directions of space in one picture

Parallel projections
Any lines that are parallel in the object are parallel in views

Perspective projections
Reproduce the effect that distant objects appear smaller than nearer objects. Lines which are parallel in nature converge towards a single point.

Types of axonometric projections
 Isometric
 Dimetric
 Trimetric

Isometric projection
 All three angles equal 120 degrees
 H, W, and D are true size along isometric axes
 Angles must be located by coordinates
 Circles appear as ellipses on all surfaces

Dimetric projection
2 angles are equal

Trimetric
All 3 angles are different

Oblique projection
Most descriptive face of object is projected parallel to projection plane, thus appearing true size

Cavalier oblique
 Front view true shape and size
 Receding axis angle normally 30, 45, 60 degrees
 Depth dimension true size

Cabinet oblique
 Front view true shape and size
 Receding axis angle normally 30, 45, 60 degrees
 Depth dimension HALF size

General oblique
 Front view true shape and size
 Receding axis angle normally 30, 45, 60 degrees
 Depth dimension is BETWEEN full and half size

GRID Command
F7
Just a visual aid, does not print

SNAP Command
F9
Allows you to specify precise coordinates when using the mouse

ORTHO Command
Allows you to only draw in the vertical or horizontal direction

DDEDIT Command
Click on a text or dimension to be edited/changed

BHATCH command
Crosshatching
Area must be closed

How many views are required to illustrate an object?
 Depends on the object
 The minimum necessary to adequately show the object's geometry

What is the thickest line drawn in an orthographic drawing?
Visible line

Which view should be the most descriptive view?
Front view

Which dimension should be minimized in orthographic views?
Depth

What are drawing methods used to provide a clearer understanding of an object, even if orthographic rules are violated?
Conventional practices

Which type of sketch is not a pictorial?
Multiview

What types of projections are not parallel projections?
Perspectives

In what type of oblique drawing is depth represented true size?
Cavalier

Auxiliary view
Used to represent the true size and shape of objects with sloping surfaces

In English thread notes, what represents the fit
 1 for loose
 2 for regular
 3 tight

In English thread notes, what represents if the thread is internal or external?
 A is external
 B is internal

In metric thread notes, what represents the tolerance?
Numbers ranging from 39. The larger the number, the larger the tolerance.

In metric thread notes, what represents the fit?
 Letters.
 E  loose fit
 G  regular fit
 H  tight fit
 Lowercase letters mean external

In metric thread notes, what represents the thread length?
 S  short
 N  normal
 L  long

T or F: The force on a truss link is called an axial force
True

How do you calculate the number of joints in a 2D truss?
L = 2 • J  3

How do you calculate the number of joints in a 3D truss?
L = 3 • J  6

What are allowable loads (working loads)?
Forces to which the links can be safely subjected.

What are the two principle modes of failure?
Failure by separation and failure by deflection.

True or False. Zeroforce members cannot improve the strength of a truss
False

How do you calculate arc length?
S=R•radian angle

How do you find zero force truss members.
If a joint connects only two truss members and no support reaction or external force is applied to the joint
If a joint connects only three members and two of the members are colinear, and no support or external force is applied, then the non colinear member is a Zero force member

In which views will circles appear as ellipses for all views?
Axonometric projections

What determines the diameter of the spotface for a spotface hole?
Left to the disgression of the machinist

In what type of sections can you show hidden lines?
Broken out sections

How do you calculate a safe loads?
 External load Largest tensile
 Force
 = 
 Max allowable Tensile External load strength

How do you calculate the factor of safety?
 Failure level Strength
  = 
 actual Internal Level member force

T or F: The factor of safety is the most conservative value?
True

When calculating internal forces, what do we assume?
The the bars are in tension. Therefore, the arrows are drawn going away from joint

