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Exploring Drafting
along an object to locate successive
features is known as chain dimensioning.
Refer to Figure 10-14. In the example
shown, three location dimensions are
omitted from dimensional chains. Many
times, an omitted dimension is a distance
that relates one feature to another. If
the information is not useful for the
manufacture of the product, it is omitted.
7. Plan your work carefully so that the
extension lines do not cross dimension
lines, Figure 10-15. Smaller (size or
location) dimensions should be placed
nearest the view, while the larger
(overall) dimensions should be placed
farther from the view.
5. Draw dimension lines parallel to the
direction of measurement. If there are
several parallel dimension lines, the
numerals should be staggered to make
them easier to read, Figure 10-13.
6. Dimensions should not be duplicated
unless they are absolutely necessary to
the understanding of the drawing. Omit
all unnecessary dimensions, Figure 10-14.
In mechanical drafting, it is common to
provide an overall dimension and only
enough location and size dimensions to
fully describe the object. When several
continuous dimensions are drawn in a
straight line or row, the least important
distance is typically omitted. Placing
several dimensions in a straight line
1.50
Preferred
5.00
3.00
1.50
Avoid
5.00
3.00
Goodheart-Willcox Publisher
Figure 10-11. Keep dimensions grouped for easier understanding of the drawing.
Preferred Avoid
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Figure 10-12. Do not extend extension lines more than halfway across a view.
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