Chapter 6 Datums and Datum Feature References 207
Copyright Goodheart-Willcox Co., Inc.
9. Rule #2 of the dimensioning and tolerancing
standard makes the RMB modifi er
applicable on datum feature references that
are _____ unless shown otherwise.
A. surfaces
B. features of size
C. A and B
D. Neither A or B.
10. A primary datum feature reference
including an MMB modifi er requires the
datum feature be simulated at its _____.
A. least material limit
B. maximum material boundary
C. actual mating envelope
D. actual produced size
11. When using datum target points to establish
a primary datum plane, at least _____ points
must be used.
A. one
B. two
C. three
D. six
12. Two datum letters separated by a dash
within a single cell of a feature control frame
indicates _____.
A. an error
B. primary and secondary datums
C. multiple (compound) datum features
D. all the letters have been used and double
letters are now in use
13. A _____ dimension must be shown between
offset surfaces that are used to establish a
single datum plane.
A. basic
B. close toleranced
C. reference
D. None of the above.
True/False
14. True or False? Regardless of the surface
variations on a part, the planes forming the
datum reference frame are always mutually
perpendicular.
15. True or False? A datum axis is not identifi ed
by placing the datum feature symbol on a
centerline.
16. True or False? A datum target area is outlined
with a line made of short dashes.
17. True or False? The order of precedence for
datums is defi ned by the order shown in the
feature control frame.
18. True or False? The datum feature references
in a feature control frame must be shown in
alphabetical order.
19. True or False? A hole may be used as a datum
feature of size, but this practice has no
practical application.
20. True or False? In regard to datum references,
based on Rule #2 of the dimensioning
and tolerancing standard, datum feature
references are assumed to apply RMB.
21. True or False? A reference to multiple
(compound) datum features means the two
features are used to establish two datums.
22. True or False? A datum feature symbol is
generally not applied to a line representing a
center plane.
23. True or False? The three datum target types
are not to be combined to establish a single
datum.
Fill in the Blank
24. The intersections of the planes in the datum
reference frame establish ____________.
25. A ____________ ____________ symbol is used
to identify a feature from which a datum is
established.
26. Datum targets may be ____________,
____________, or ____________.
27. Datum ____________ is determined by
the order in which datum features are
referenced in the feature control frame.
28. To identify a cylinder as a datum feature,
a datum feature symbol is placed on the
____________ dimension.
29. A datum feature that is a fl at surface may be
identifi ed in a drawing view by placing the
datum feature symbol on a(n) ____________
line from the surface.
30. A datum feature symbol applied to the
width dimension on a rectangular slot
establishes a datum ____________ at the
center of the slot.
31. A secondary datum feature reference
including an MMB modifi er requires
the datum feature be simulated at its
____________ material boundary.
32. A minimum of ____________ points are
required to establish a secondary datum
plane when using datum target points.