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AutoCAD and Its Applications—Advanced
Copyright Goodheart-Willcox Co., Inc.
Constructing Features on Solid Constructing Features on Solid
Models Models
A variety of machining, structural, and architectural features can be created using
some basic solid modeling techniques. The features discussed in the next sections are
just a few of the possibilities.
Counterbore and Spotface
A counterbore is a recess machined into a part, centered on a hole, that allows the
head of a fastener to rest below the surface. Create a counterbore as follows.
1. Draw a cylinder representing the diameter of the hole, Figure 8-29A.
2. Draw a second cylinder that is the diameter of the counterbore and center it at the
top of the first cylinder. Move the second cylinder so it extends below the surface
of the object to the depth of the counterbore, Figure 8-29B.
3. Subtract the two cylinders from the base object, Figure 8-29C.
A spotface is similar to a counterbore, but is not as deep. See Figure 8-30. It
provides a fl at surface for full contact of a washer or underside of a bolt head. Construct
it in the same way as a counterbore.
Countersink
A countersink is like a counterbore with angled sides. The sides allow a fl at-head
machine screw or wood screw to sit fl ush with the surface of an object. A countersink
can be drawn in one of two ways. You can draw an inverted cone centered on a hole
Point on the
cutting plane
A
B
Point on the
cutting plane
Point on the
cutting plane
Figure 8-28.
Slicing a solid using
the
3points
option.
A—Specify three
points to define the
cutting plane. B—
The resulting slice.