slide set 5 – dimensioning i - orzo.union.eduorzo.union.edu/~khetans/teaching/bng101/slide set 5 -...
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Aspects of good dimensioning
1) Technique of dimensioning – standard appearance of lines, arrowheads, etc.
2) Placement of dimensions – legible, easy to find, easy to interpret
3) Choice of dimensions – function; ease of manufacturing
Aspects of good dimensioning
1) Technique of dimensioning – standard appearance of lines, arrowheads, etc.
2) Placement of dimensions – legible, easy to find, easy to interpret
3) Choice of dimensions – function; ease of manufacturing
Tolerance is the actual amount that the feature is allowed to vary from what is specified by the drawing. Example: All tolerances +/- 0.02 inch unless otherwise noted.
Dimensioning systems
U.S. (IPS) • uses decimal inch values • No zero to the left of the decimal for
values <1 inch • Trailing zeros are used
Metric (MMGS) • Requires all measurements to be in mm • “mm” label not needed on each
dimension • No trailing zeroes are used
Geometric breakdown
1) Size dimensions (show sizes of simple geometric shapes)
2) Location dimensions (locate elements with respect to one another)
Geometric breakdown
1) Size dimensions (show sizes of simple geometric shapes)
2) Location dimensions (locate elements with respect to one another)
Size dimensions
• Two of the dimensions usually placed on the principal (front) view • Third dimension located on one of the other two views
Example 1 for do’s and don’ts
• How should the below dimensioning be adjusted (do a rough sketch on your paper)?
Practice exercise
• Fill in the missing dimensioning elements (hint: there is a hole and cylinder in the object – apply the rules we just learned!)