How mating parts or assemblies fit together with component parts is referred
to as fit, clearance fit, interference fit, or transition fit.
FIT: Fit is the general range of tightness resulting from the application of a
specific combination of allowance and tolerances in the design of mating
CLEARANCE FIT: When a clearance results while you are assembling
mating parts, the limits in size produced by that clearance is called the
INTERFERENCE FIT: When an interference results while you are
assembling mating parts, the limits in size inferred by that interference is
called the interference fit.
TRANSITION FIT: The limits in size resulting from a clearance or
interference that results when assembling mating parts.
Figure 3-38 illustrates the differences between fits.
Figure 3-38.The difference between: A. An interference fit, and
B. A transition fit.
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