Model Documentation

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Model Documentation
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Working Drawing

• Documentation
• Once a design has been researched and approved,
  the part is sent to be prototyped or
  manufactured. Appropriate documentation is needed
  to communicate the idea to everyone in the
  company. This is the most difficult, time
  consuming, yet the most important part of
  engineering communication. These documentation
  are called working drawings.

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What are Working Drawings?

• Working drawings are a complete set of documents
  that specify how an object will be manufactured
  and assembled. Each set should include
• Part Drawings
• Assembly Drawings
• Parts List
• Any Special Specifications or Instructions.

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Working Drawings

• Elements of Working Drawings
• Drawing Layout
• Drawing Views
• Dimensioning
• Annotations
• Multiple Features

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Drawing Layout

• Elements of Drawing Layout
• Sheet Styles and Sizes
• Borders
• Title Block
• Scale
• Revision Block

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Sheet Sizes
American National Standards Institute ANSI
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Title Block

• A box found in the lower right hand corner of a
  drawing.
• It contains pertinent information on the part
• Drawing Number
• Scale
• Material
• Title or Description
• Company
• Tolerances

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Title Blocks
Zoning is used to find specific locations on
the drawing. Usually shown in numbers and
letters.
General notes and information. Located here you
will see information on, fillet and rounds,
tolerances, and other general information
that would take up too much space on the drawing
if repeated on every feature.
Remember working drawings are made of
many different types of drawings and there are
usually more than one sheet that goes with a
design.
Title of the project. As opposed to a specific
part.
ANSI Large style title block. All title blocks
should include the following information.
Name of person who checked the drawing. Just
like first drafts of papers written in English
class, drawings go through many revisions.
Scale of the part is important so the person
being communicated to can get an idea of what
the part looks like.
Another person will check the drawing and
approve the part for manufacture.
Size of sheet. Very valuable when printing.
Company name. Many times companies will create
their own borders and their logo will appear
also.
Name of person who did the drawing.
Specific part name in relationship to the total
design.
Documentation of how many times the drawing has
been changed.
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Scale

• When objects can be drawn using the actual
  dimensions, it is referred to as full scale or
  11. Some objects are drawn larger than actual
  size, so one can clearly see details and
  dimensions these can be as large as 101.
• Scale is represented as an equation. The left
  side is the drawing size and the right side
  represents the part.

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Scale
The bolt is drawn five times larger than actual
size
Scale 51

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Drawing Views

• For clear and accurate dimensioning and
  specification of a part the drawing may need a
  variety of views.
• The five basic views are
• Orthographic
• Isometric
• Section
• Auxiliary
• Assembly

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Orthographic (Multiview Drawings)

• Orthographic Projection is also known as a
  Multiview drawing. Orthographic projection is a
  way to project a view based on a line of sight
  that is perpendicular to that view. There are
  six views to any object as shown in the next
  slide.

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Orthographic (Multiview Drawings)
The arrows represent the line of sight
associated with each view.
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Orthographic Principal Views
Note how the views are oriented. Each view
is adjacent to the other as if they were unfolded
from a 3D shape.
Front, Top and Right views are used most often.
You can see how other views resemble these
three except they are not as clear due to hidden
lines.
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Orthographic Angle of Projection

• The example you have just seen is shown in the
  third angle of projection. This is the standard
  in the United States and Canada.

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Orthographic 3rd Angle Projection
Views are projected onto planes that exist on
the face of that view. Arrows show the
direction of the projection
ISO Symbol
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Orthographic View Selection

• Steps in selecting the front view.
• Most natural position or use.
• Shows best shape and characteristic contours.
• Longest dimensions.
• Fewest hidden lines.
• Most stable and natural position.
• Relationship of other views.
• Most contours
• Longest side
• Least hidden lines
• Best natural position

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Orthographic View Selection
Most natural position.
Longest Dimension
Best shape description.
No hidden lines.
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OrthographicView Selection Numbers

• A decision must be made in accordance to how many
  views are needed on a drawing. Generally, three
  views are needed and, in some cases, only one or
  two.

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Orthographic Example
2 Orthographic views are used instead of three.
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Orthographic Example
3 View Orthographic Drawing
Dimensions to show size and shape.
Title Block gives general information about the
part.
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Placing and Locating Orthographic Views

• Which orthographic views you need are based on
  the same rules we had in the sketching unit.
• Steps in selecting the front.
• Most natural position or use.
• Shows best shape and characteristic contours.
• Longest dimensions.
• Fewest hidden lines.
• Most stable and natural position.
• Relationship of other views
• Most contours.
• Longest side.
• Least hidden lines.
• Best natural position.

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Placing and Locating Orthographic Views
Parts are evenly spaced.
Enough white space is left for dimensioning.
Third angle projection is used.
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Isometric Views

• An isometric view is a pictorial view inserted in
  an orthographic drawing.
• An Isometric, meaning equal measure, is created
  by rotating the object at equal angles to the
  projection plane in order to appear inclined and
  to show three faces.

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Isometric
Note one pictorial view shows height width and
depth.
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Isometric Views
Isometric View
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Section Views

• When a part has a lot of interior details, hidden
  lines can make the part hard to understand and
  dimension. To see the interior of these parts,
  we cut some of the part away. This allows for
  details to be seen clearly, as well as, giving us
  alternative locations to properly dimension the
  part.

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Sectional Views

• Types of Sectional Views
• Half
• Full
• Offset
• Removed
• Revolved
• Broken-out
• Aligned

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Half Section
Notice how the cutting plane line runs through
the center of the part and there is no arrow
head.

• In a half section, one quarter of the part is cut
  away. This is done with symmetrical parts where
  you would like to show the outside, as well as,
  the inside details.

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Full Section
A full section is a view that shows what the
object looks like if it were cut in half.
A cutting plane line is used to indicate how the
front view was cut. It is also labeled in case
another section is necessary. The arrows should
point in the line of sight as you are looking
straight on at the section.
Section lines called Hatch lines are used to show
where the part is solid. This helps to see the
detail that would be normally blocked and only
shown as hidden lines.
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Offset Section
Interior features not in line with each other can
be shown in an offset section view. Note how the
cutting plane line changes and follows the center
of each feature.
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Revolved Sections

• Used when an object has a constant shape
  throughout the length that cannot be illustrated
  in an external view.
• The section is revolved 90 degrees. It may be
  represented one of two ways, either broken away
  or not.

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Not Broken Away Revolved Section
Section is revolved 90 degrees
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Broken Away Revolved Section
Section is revolved 90 degrees and broken away
from part
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Broken-out Section Views

• A small portion of an object may be broken away
  to clarify an interior surface or feature. No
  cutting plane line is used.

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Broken-out Section View
Section exposes the interior surfaces
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Auxiliary View

• To accurately view the true dimensions of an
  inclined surface, one must create a view at 90
  degrees from that inclined face. This is
  referred to as an Auxiliary View. This allows us
  to view the surface in its true size and shape.

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Primary Auxiliary View
In order to see a feature in its true size and
shape, we must look at it straight on or
perpendicular to the plane in which the feature
exists. Note that in this view (the auxiliary
view) the slotted hole is true size and shape.
Many times a feature on a part cannot be seen in
true size and shape. When this is the case we
use an auxiliary view.
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Detail Views

• A drawing of an individual part that contains all
  the information needed to manufacture the object
  is referred to as a Detail Drawing. These
  drawings contain all the specifications,
  dimensions and views needed for production.
• A Detail View may be necessary to illustrate
  small features on a part. This is achieved via
  breaking out and enlarging the feature.

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Detail View
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Assembly Drawings

• Many products are composed of several different
  parts assembled into one. A drawing showing the
  working relationship of those parts is called an
  Assembly Drawing. This is achieved using views
  in the usual positions showing the layout out of
  the parts. A parts list is included on the
  drawing to identify the name, material and number
  of each piece.

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Assembly Drawings

• General
• Exploded
• Explosion factor
• Trails
• Tweaks

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General Assembly Drawings

• General Assembly Drawings are a set of drawings
  that include the detail drawings, assembly
  drawings and parts list needed in the production
  of an assembled object.

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General Assembly Drawing
Parts List
Includes all detail drawings of each part
Includes the Assembly Drawing
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Exploded Assemblies
An Exploded Assembly shows all the parts removed
from each other and aligned along axis lines
Identification numbers are generally placed
inside balloons and point to the part with a
leader line
Trials show the initial path the components moved
along when the view was exploded
The explosion factor is the distance the parts
have been separated from each other.
A parts list is included on the drawing to
identify the name, material and number of each
piece.
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Parts List
Specific part number. All parts will have
specific numbers assigned to them. This makes
computer data processing easier.
Description of part or the name.
Item number on the drawing.
How many parts are included in the assembly.
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Explosion Factor

• The explosion factor is the distance the parts
  have been separated from each other.

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Trails

• Trails show the initial path the components moved
  along when the view was exploded

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Tweaks

• Is adjusting the distance or location of a part
  in an exploded assembly.

After
Before
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Dimensioning

• Views and dimensions provide a clear description
  of the shape and size of parts and their
  features.
• Parts are fun to design, but dimensioning the
  part to be manufactured can be difficult.
• Dimensioning takes time and patience to get it
  right. Errors in a drawing will most likely be
  found in the dimensioning.

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Decimal
The most common form of dimensioning uses the
decimal system. Precision is set by the number
of decimal places.
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Architectural
The Architectural Style of dimensioning is quite
different from the decimal. Dimensions are shown
in feet and inches.
Arrow heads can be the same as decimal
dimensioning or can be displayed as architectural
ticks.
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Engineering
The engineering style of dimensions is shown
here. The inch units are in decimal and feet and
inches are displayed similar to the Architectural
style of dimensioning.
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Surveyor
B
Surveying dimensions are given in north and south
directions. The example here is said to be North
46 degrees, 48 minutes, 39 seconds West. This
indicates the line points in the northwest.
Normally a distance is given.
A
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Dual
Dual dimensioning is a type that shows both
metric and inch units on the same drawing. There
are two methods position and bracket.
Position method Places the metric dimension
over the inch dimension. Another acceptable
practice is to place the metric dimension
before the inch dimension with a slash after the
metric dimension.
Bracket method The bracket method places the
metric dimension in brackets. The metric
dimension can be placed above or to the right.
Exactly what the units represent, needs to be
noted on the drawing.
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Dimensioning

• Standards
• Types of Dimensions
• Linear
• Dimensioning Arcs and Circles
• Reference Dimensions
• Dimensioning Special Features

• Methods
• Rules and Practices
• Dimensioning Angles
• Dimensioning Curved Features
• Coordinate Dimensioning
• Tolerance

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Standards

• In order for the drawings to be dimensioned so
  that all people can understand them, we need to
  follow standards that every company in the world
  must follow. Standards are created by these
  organizations
• ANSI -MIL
• ISO -DOD
• DIN -CEN
• JIS

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Standards Institutions

• ANSI - American National Standards Institute -
  This institute creates the engineering standards
  for North America.
• ISO - International Organization for
  Standardization - This is a world wide
  organization that creates engineering standards
  with approximately 100 countries participating.

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Standards Institutions

• DIN - Deutsches Institut für Normung - The German
  Standards Institute created many standards used
  world wide such as the standards for camera film.
• JIS - Japanese Industrial Standard - Created
  after WWII for Japanese standards.
• CEN - European Standards Organization

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Standards Institutions

• The United States military has two organizations
  that develop standards.
• DOD - Department Of Defense
• MIL - Military Standard

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Dimensioning Methods

• Dimensions are represented on a drawing using one
  of two systems, unidirectional or aligned.
• The unidirectional method means all dimensions
  are read in the same direction.
• The aligned method means the dimensions are read
  in alignment with the dimension lines or side of
  the part, some read horizontally and others read
  vertically.

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Aligned Dimensions
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Unidirectional Dimensions
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Types of Dimensions

• Their are two classifications of dimensions size
  and location.
• Size dimensions are placed in direct
  relationship to a feature to identify to specific
  size.
• Location dimensions are used to identify the
  relationship of a feature to another feature
  within an object.

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Size and Location Dimensions
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Rules and Practices

• Accurate dimensioning is one of the most
  demanding undertakings when designing parts.
• Use the checklist to insure you have followed the
  basic dimensioning rules.

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Dimensioning Checklist

• Each dimension should be written clearly with
  only one way to be interpreted.
• A feature should be dimensioned only once.
• Dimension and extension lines should not cross.
• Dimension each feature.
• Dimension features or surfaces to a logical
  reference point.

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Dimension Checklist

• Dimension circles with diameters and arcs with a
  radius.
• A center line should be extended and used as an
  extension line.
• Dimension features on a view that clearly shows
  its true shape.
• Dimension with enough space to avoid crowding and
  misinterpretation.

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Dimension Checklist

• Extension lines and object lines should not
  overlap.
• Dimensions should be placed outside the part.
• Center lines or marks should be used on all
  circles and holes.

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Linear Dimensioning

• The accuracy of the final product is determined
  by the dimensions on the drawing. If all the
  dimensions originate from a common corner of the
  part, the object will be more accurate. This is
  referred to as Datum Dimensioning. Datum's
  insure the tolerance or errors in manufacturing
  do not accumulate.

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Linear Dimensioning

• Dimensioning from feature to feature is known as
  Chain Dimensioning. It is commonly used and easy
  to layout. It does have possible consequences in
  the manufacturing of a part. Tolerances can
  accumulate making the end product larger or
  smaller than expected.

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Chain Dimensioning
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Chain Dimensioning
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Datum Dimensioning
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Dimensioning Angles

• Angled surface may be dimensioned using
  coordinate method to specify the two location
  distances of the angle.
• Angled surfaces may also be dimensioned using the
  angular method by specifying one location
  distance and the angle.

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Dimensioning Angles
Coordinate Method
Angular Method
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Dimensioning Arcs and Circles

• Arcs and circles are dimensioned in views that
  show the arc or circle.
• Arcs are dimensioned with a leader to identify
  the radius in some cases a center mark is
  included.
• Circles should have a center mark and are
  dimensioned with a leader to identify the
  diameter.

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Dimensioning Curved Features and Arcs
Small arcs do not need center marks. Arrow
can be outside.
Large Arcs use center marks.
Use a capital R for dimensioning arcs.
Or the arrow can be inside for small arcs.
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Diameters
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Dimensioning Curved Features
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Reference Dimensions
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Chamfers
External chamfer for 45 degree chamfers only.
There are two options.
External chamfer for angles other than 45 degrees.
Internal chamfers.
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Fillets and Rounds
Use a capital R for dimensioning the arc.
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Conical Tapers
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Slot Dimensioning
The two methods shown on the left are the
acceptable methods for dimensioning
slotted holes.
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Hole Location Polar Coordinates
Polar dimensioning locates features by the use of
angles
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Rectangular Coordinates
Rectangular coordinates use linear dimensions to
dimension the hole locations
multiple holes are dimensioned from another
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Rectangular Coordinates
Linear Coordinates are used to locate hole
dimensions
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Keyways
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Tolerance Dimensioning

• Perfection is difficult to obtain. A tolerance is
  associated with dimensions on a drawing to
  illustrate the permissible variation in size or
  location. A tolerance specifies how much the
  dimension may vary from the designated size on
  the drawing.

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Tolerance Limits

• The largest size an object can be made to is the
  upper limit. The smallest size an object can be
  made to is the lower limit.

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Dimensioning Tolerances
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Allowances
Some parts fit together requiring an allowance
to be specified. It is the tightest possible
fit between two parts
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Alphabet of Lines
Short Break Line A freehand drawn line that
shows where a part is broken to reveal detail
behind the part or to shorten a long continuous
part. (See example of Long Break Line on the
next slide.)
Hidden Line Lines used to show interior detail
that is not visible from the outside of the
part.
Center Line Lines that define the center of
arcs, circles or symmetrical parts. They are
half as thick as an object line.
Section Lines Lines are used to define where
there is material after a part of the object is
cut away.
Construction Line Very lightly drawn lines used
as guides to help draw all other lines and
shapes properly. Usually erased after being
used.
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Alphabet of Lines
Long Break Lines Break lines are used To
indicate we have shortened the drawing to use
our space more efficiently.
Dimension lines are used to show distance.
Arrows are drawn on the ends to indicate where
the dimension line starts and ends. The actual
distance is placed in the middle of this line.
Dimension lines are used in conjunction with
extension lines to properly dimension objects.
Extension lines are used to show where a
dimension starts and stops on an object. The
line should begin about 1/16 away from the part
to prevent confusion with the object lines
Cutting Plane Line A line used to designate
where the part has been cut away to see detail.
The arrows point in the direction that you are
looking.
Leader lines are used to show dimensions of arcs
or circles. They are also used to connect notes
with features. The line with the arrowhead
should be diagonal while the Line connecting to
the note is horizontal
How many lines from the previous slide can you
identify here?
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Line Types and Specifications
Arrow heads point directly to the object that is
being dimensioned or the extension lines at the
end of the dimension. Arrow heads are made 3
times as long as they are wide.
Each succeeding dimension line should be 6mm
from the previous one.
Extension lines are used to establish the extent
of the dimension. Arrows from the dimension
line should touch the extension line. Extension
lines should have a small space between the
end and the object that is being dimensioned.
The extension line should also extend 3mm beyond
the last dimension line noted.
The dimensioning system used here is
unidirectional. This is the most common.
Another system you may see is aligned. If this
drawing were using the aligned system the
dimension, we are pointing to would be read
horizontally from the right of the drawing or
turned counter clockwise 90 degrees.
Dimension lines are used to identify distances of
features. It has arrow heads at the end to
identify the extents. There is a break in the
middle to place the dimension. Dimension lines
should be 10mm away from the object that is
being dimensioned.
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Annotation
Local notes identify specific features that need
a special operation. Hole notes are one such
example. This note is placed with leaders at the
location of the feature it pertains to.
General notes are information that pertains to
the entire drawing, unless specified in a local
note. General notes are usually placed in the
title block.
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Hole Dimensioning
Holes are specified with numbers and symbols.
Diameter
Through
Depth
Counterbore or Spotface
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Hole Dimensioning
Finish Mark
Countersink
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Hole Dimensioning
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Thread Notes
This number can be 3,4,5,6,7,8,9. It is
the grade of tolerance in the threads from fine
to course. The H is for allowance G would be a
tight allowance and H is no allowance.
Prior to THRU you may have an LH for left hand
thread.
Finally THRU or a depth may be specified.
M for Metric
Nominal Diameter
Pitch of the threads.
Notes the threads are cut all the way through the
hole. Depth can be specified here as well as LH
for left hand thread.
Identifies course or fine thread. In this case
course. F for fine.
Major Diameter
Threads per Inch
Threads are dimensioned with the use of local
notes. We will discuss two methods the ISO and
the Unified National Thread method.