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BNG 101 – Engineering Graphics
Slide Set 6 – Dimensioning II
Drawing scale and dimensioning
Drawing scale is noted in title block Older drawings may indicate “NTS”; when using CAD, take the time to correct the geometry to reflect changes
Drawing scale and dimensioning
• Keep dimensioning and lettering at small scales
Are reduced size working prints going to be used? May increase lettering size, dimensioning arrows, etc. by 50%
Direction of dimension values and notes
Dimension values and notes should be lettered horizontally
Exception: Coordinate dimensioning
Decimal and mm equivalents
In title block: “All measurements in mm unless otherwise noted” or “All measurements in inches unless otherwise noted”
Millimeter dimensioning example
Decimal inch dimensioning example
How many significant digits?
It is difficult to maintain tolerances smaller than a few thousands of an inch!
Example 0.001’’ is how many millimeters? __________________________ Generally, round to (at most) two digits to the right of the decimal point
Dual dimensioning
Dimension symbols
Dimension symbols – example
Rules for placing dimensions properly
Rules for placing dimensions properly
Rules for placing dimensions properly
Rules for placing dimensions properly
Exercise: which view is clearer and why?