Solid-Shank Rivets.
Rivets are manufactured in two head styles:
universal and countersunk (Figure 1-11).
Both head styles are used
in interior and exterior locations.
The universal head is shaped
like a mushroom.
Because of the added strength of the head style,
the universal head rivet is used extensively throughout the aircraft.
The countersunk rivet is used where flushness is required.
The top
of the countersunk head fits flush with the surface of the riveted
material. This is accomplished because the rivet is flat-topped and
undercut to allow the head to fit into a countersunk or dimpled hole.
When aerodynamics or clearance is required, the countersunk rivet is
used.
Figure 1-11.
Head Styles for Solid-Shank Rivets.
Blind Rivets.
This section covers only the most common types of
self-plugging rivets.
Information on other types of self-plugging
rivets may be obtained from the United States Army Aviation Systems
Command, 4300 Goodfellow Boulevard, St. Louis, MO 63120, or from the
rivet manufacturer.
When access to both sides of a riveted structure or structural part
is impossible or when limited space does not permit using a bucking
bar, blind rivets must be used.
These rivets have characteristics
that require special installation tools and installation and removal
procedures.
Because these rivets are often installed in locations
where one head, usually the shop head, cannot be seen, they are
commonly called blind rivets. The blind rivets used on Army aircraft
and discussed here are self-plugging (friction and mechanical lock).
Friction Lock.
Self-plugging friction lock rivets consist of a
rivet head with a
hollow shank or sleeve and a stem that extends
through the shank.
The rivet head styles are the same as the solid-
shank rivets. Two
common styles, shown in Figure 1-12, are in use.
The stem may have
a knob on the upper portion or it may have a
serrated portion.
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