Chapter 10 Dimensioning
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8. When all dimensions on a drawing are in
inches, the inch symbol (″) should not be
used. However, the drawing should have
a note stating “UNLESS OTHERWISE
SPECIFIED, ALL DIMENSIONS ARE
IN INCHES” (or “MILLIMETERS,”
as applicable). Dimensions on metric
drawings are in millimeters (mm)
unless otherwise noted. Special rules
for dimensioning metric drawings are
discussed later in this chapter.
9. Numerals and fractions must be drawn
to the proper height in relation to one
another, Figure 10-16. Proper sizes for
lettering fractional numbers are discussed
in Chapter 8.
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Figure 10-13. When there are several parallel dimension lines, numerals should be staggered for easier reading.
The symmetry centerline indicates that the dimensions are centered with respect to each other.
D D
D
D
D
D
D
2X Ø
D D
D
D
D
D
D
Ø Ø
D
D
D
D
A B
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Figure 10-14. Avoid duplicating dimensions unless they are necessary to understand the drawing. A—Properly
dimensioned object. B—Unnecessary dimensions are removed.
Preferred Avoid
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Figure 10-15. Crossing lines can be kept to a minimum
if the shortest dimensions (size or location dimensions)
are placed next to the object outline. Longer dimensions
(overall dimensions) are placed farther from the drawing.
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