Machine Drawings, Continued
Gerneral terms
Figure 4-29 shows the methods of indicating tolerances.
(Continued)
Figure 4-29.—Methods of indicating tolerance.
SURFACE TOLERANCES: Toleranced surfaces have certain geometric
characteristics such as roundness or perpendicularity to other surfaces. A
feature control symbol is made of geometric symbols and tolerances, which
may include a datum reference and indicates surface tolerances. A datum is a
surface, line, or point from which a geometric position is determined or from
which a distance is measured.
Figure 4-30 illustrates a feature control frame indicating a datum reference.
Figure 4-30.—Feature control frame indicating
a datum reference.
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