1. Part and Drawing Dimensioning
Professor Egli
EGTECH 10
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2. Dimensions - General
Dimensions are used to describe the shape of the part or assembly shown in a drawing view.
Dimensions in a SolidWorks drawing are associated with the model.
Changes in the model are reflected in the drawing.
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3. Dimension - Types There are two main types of dimensions:
Model dimensions: dimensions created as you create each part feature. You then insert those dimensions into the various drawing views.
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4. Dimension - Types (Cont:)
There are two main types of dimensions (cont):
Reference dimensions: Can be added in a drawing document (driven dimensions). You can’t edit the value of reference dimensions to change the model.
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5. Part Dimensioning - Systems
There are basically three types of dimensioning systems use in creating parts and drawings:
U.S. - ANSI standard for U.S. dimensioning use the decimal inch value. When the decimal inch system is used, a zero is not used to the left of the decimal point for values less than one inch, and trailing zeros are used.
The U.S. unit system is also known as the Inch, Pound, Second (IPS) unit system.
Leading zeros, trailing zeros, and number of zeros to the right of the
decimal point are important in dimension and tolerance display.
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6. Part Dimensioning – Systems (Cont:)
There are basically three types of dimensioning systems use in creating parts and drawings:
Metric - ASME standards for the use of metric dimensioning required all the dimensions to be expressed in millimeters (mm). The (mm) is not needed on each dimension, but it is used when a dimension is used in a notation. No trailing zeros should be used.
The Metric or International System of Units (S.I.) unit system in drafting is also known as the Millimeter, Gram Second (MMGS) unit system.
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7. Part Dimensioning – Systems (Cont:)
There are basically three types of dimensioning systems use in creating parts and drawings:
Dual Dimensioning - Working drawings are usually drawn with all U.S. or all metric dimensions. Sometimes the object manufactured requires using both the U.S. and metric measuring system.
In this illustration, the secondary units (mm) are displayed in parenthesis.
The Primary units are inches.
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8. Part Dimensioning - Goal
There are different rules for the display of decimal dimensions and
tolerances based on millimeter and inch units.
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9. Part Dimensioning - Goal (Cont:)
What is the goal when dimensioning a part?
Dimensions should be given in a clear and concise manner and should include everything needed to manufacture and inspect the part exactly as intended by the designer.
Add Reference dimensions if needed
Add Notes (Local and Global) if needed
Do NOT over dimension the view!
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10. Part Dimensioning - General (Cont:)
Dimensions of size
How big is it?
height, width, depth, diameter, etc.
Dimensions for location
Where is it in space relative to the origin?
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11. Part Dimensioning - Angle Example
The design of a part may require some lines to be drawn at an angle.
The degree is indicated by a symbol º placed after the numerical value of
the angle.
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12. Part Dimension - Angle Example (Cont:)
You can insert this dimension
Always position the diameter dimension of a hole up and off the model.
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13. Part Dimension - Angle Example (Cont:)
You can insert this dimension
instead of the .5 dimension.
Which is correct?
Note the gap with the dimensions lines and the stager dimensions!
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14. Part Dimension - Angle Example Cont:
You can insert both
dimensions
but one as a
reference dimension
ON a Drawing!
Note: A Reference dimension with no tolerance!
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15. Part Dimensioning - Cylinder
What is the Base Sketch Plane?
What would the front view look like?
What would the Right view look like?
What views would you dimension in?
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16. Part Dimensioning - Cylinder
How would you dimension the Cylindrical part in the Horizontal Position?
Is there a hole dimension? Do you need both views?
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17. Part Dimensioning - Cylinder
Cylindrical part in the Horizontal Position – Rectangular view
Think of the bushing in the Term Project. Remember Gaps!!!!
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18. Part Dimensioning – Cylinder with a Hole
What is the Base Sketch Plane for the part?
Think display mode.
What would the Front view look like?
What would the Right view look like?
How would you dimension the part?
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19. Part Dimensioning - Cylinder with a Hole: Example 1
Hidden Lines Visible
Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view.
Remember dimension gaps.
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20. Part Dimensioning - Cylinder and Hole1
What would the Front view look like?
What would the Right view look like?
How would you dimension the part?
Note A diameter is identified according to ANSI standards by using the symbol Ø preceding the dimension.
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21. Part Dimensioning - Cylinder and Hole1
Which one
is correct?
Note A diameter is identified according to ANSI standards by using the symbol Ø preceding the dimension. Note: The model is displayed in millimeters.
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22. Part Dimensioning - Cylinder and Hole2
What is the Base Sketch Plane?
What would the Front view look like?
What would the Right view look like?
What views would you dimension in?
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23. Part Dimensioning - Example 3
Center Mark
Note
Centerline
Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view.
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24. Part Dimensioning - Cylinder with a Hole: Example 4
Cylindrical part - Rectangular view. Holes are dimensioned by giving their diameter and location in a circular view.
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25. Part Dimensioning - Radial Dimensions
Foreshortened leader lines and extension lines used on large arcs.
Cylindrical part – Rectangular view. Holes are dimensioned by giving their diameter and location in the circular view.
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26. Part Dimensioning - Square features
Insert the Square symbol if the part is square – not cylindrical. Display in the Rectangular view.
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27. Part Dimensioning - Holes
Holes are often dimensioned in relation to one another and to a finished surface.
The preferred method of placing these dimensions is illustrated.
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28. Part Dimensioning - Arc
An arc is always dimensioned by giving the radius. ANSI standards require a radius dimension to be preceded by the letter (symbol) R as illustrated.
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29. Part Dimensioning - General
Smaller (Shorter) dimensions are located closest to the feature line,
followed by dimensions of length. Dimensions nearest to the feature line
should be at least .375inches or (10mm) away from the model and succeeding
parallel dimension lines should be at least .250 inches (6mm) apart.
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30. Part Dimensioning - Placement with Polar Coordinates
Can you create Construction
geometry in a part?
geometry in a drawing?
To dimension features on a round or symmetric component use Construction
geometry and display sketch entities either on the part or in
the drawing.
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31. Part Dimensioning - Times and By Symbol (X) in a Drawing
The X symbol in a drawing can also be used to indicate the work “by”. For instance, when a slot that has a given width by a specified length
or a chamfer that has equal sides (.14 X.14)
When used to imply the word “by” a space must precede and follow the capital X symbol.
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32. Part Dimensioning - Times and By Symbol (X) in a Drawing (Cont:)
If the same feature in the model is repeated on the drawing (such as 6 holes of the same diameter and in a
pattern) the number of times the instruction applies is
called out using the symbol X.
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33. Part Dimensioning - ANSI Hole Depth Symbol
Features, such as blind holes and
counterbores, must have a depth
called out to fully describe
their geometry.
Deep or Depth Symbol
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34. Part Dimensioning - ANSI Countersink Symbol
The symbol denotes a requirement for
countersunk holes used to recess
flathead screws.
Countersink Symbol
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35. Part Dimensioning - ANSI Counterbore Symbol
The symbol denotes a requirement for
counterbored holes used to recess
machine screw head.
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36. Part Dimensioning - ANSI Counterbores and Countersinks
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37. Part Dimensioning - Screw Threads - Drawings Notes
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38. Part Dimensioning - General
Remember dimension line Gaps!!!!
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39. Part Dimensioning - Continuous Method
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40. Part Dimensioning - Good Practice
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41. Part Dimensioning - Good Practice
Never place dimension on the object!
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42. Part Dimensioning - Over-Dimensioning
On the Model. You can use Reference dimensions
on a drawing!
Correct (BUT NO GAP)
Avoid with not gap
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43. Part Dimensioning - Coordinate or Baseline Dimensioning
Gap
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44. Part Dimensioning - Center Dimensioning
Gap
Note: The order, location and centering of the dimension and dimension lines!
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