Figure 4-47.--Incorrectly driven rivets.
Figure 4-48.--Removal of rivets.
and higher than the dimensions given, more driving is
has been formed over heavy material, such as an
necessary. If it is wider and shallower, it must be
extruded member, the formed head can be drilled
removed and replaced.
through and sheared off. If the material is thin, it may be
necessary to drill completely through the shank of the
Rivet Removal
rivet, and then cut the formed head with
diagonal-cutting pliers. The remainder of the rivet may
Rivets must be removed and replaced if they show
then be drifted out from the inside.
even the slightest deformity or lack of alignment.
Reasons for replacing rivets are as follows: rivet marred
BLIND RIVET INSTALLATION
by bucking bar or rivet set; rivet driven at slant or shank
bent over; rivet too short, causing the head to be
The description and use of blind rivets are covered
shallow; rivet pancaked too flat from overdriving;
in chapter 2 of this manual. The special tools and
sheets spread apart and rivet flashed between the
installation and removal methods are covered in the
sheets; two rivet heads not in alignment; and head of
following sections. Selection of the proper equipment
countersunk rivet not flush with outside surface or
depends on a number of variables: space available for
driven below surface. Examples of these incorrectly
equipment, type of rivets to be driven, and the
driven rivets are shown in figure 4-47.
availability of air pressure.
When you are removing rivets, be careful not to
Installation Tools
enlarge the rivet hole. This will require you to use a
larger size rivet for replacement. To remove a rivet, file
One of the tools used for driving huck rivets is the
a flat surface on the manufactured head. It is always
CP350 blind rivet pull tool. See figure 4-49. The nose of
preferable to work on the manufactured head rather
than on the one that is bucked, since the former will
always be more symmetrical about the shank. Indent
the center of the filed surface with a center punch, and
use a drill of slightly less than shank diameter to drill
through the rivet head. Remove the drill and, with the
other rivet end supported, pry or lightly tap off the head
with a drift punch. If the shank is too tight after the
removal of the head, the shank should be drilled out.
However, if the sheet is firmly supported from the
opposite side, the shank may be punched out with a
drift punch. See figure 4-48.
The removal of flush rivets requires slightly more
skill. If the formed head on the interior is accessible and
Figure 4-49.--Self-plugging rivet (mechanical lock) pull tool.
4-26
