SPRING 2018

116
THE DISTRIBUTOR’S LINK
ANTHONY Di MAIO STRUCTURAL TYPE BLIND RIVETS from page 34
Multi-Grip is another advantage to the Monobolt and
the Interlock Structural Blind rivets. One size rivet will
accommodate many work thicknesses forces exist. Both
having a locked portion of the mandrel in the set rivet
body, avoiding the need to purchase many length rivets.
This special nosepiece has a raised ring around the
hole of the nosepiece that the mandrel is inserted into to
set the rivet. The raised ring engages the locking shirt of
the mandrel and flairs out the skirt into the body of the
structural blind rivet. The locking skirt is forced into the
inside wall of the rivet body as the setting tool pulls the
There are 4 sizes of Monobolts and Interlocks: mandrel and when the tensile strength of the mandrel
RIVET NO. GRIP RANGE
is reached, the mandrel breaks. The mandrel breaks at
64 .062-.250
the pre-determined tensile value and at a pre-determined
67 .214-.437
breaking point of the mandrel.
86 .080-.375
The pre-determined breaking point, or breaking
810 .350-.625
position of the mandrel, is a groove that has been formed
There are 2 diameters the Monobolt and Interlock is
manufactured to, and that is “6”= 3/16 (.187) Diameter
and “8” = 1/4 Diameter (.250). If you set any one of the
above structural blind rivets and set it in the following
ways:- one with no work thickness and one at maximum
grip range, you will see that the mandrel material inside
the body of the set rivet, is at the same position in both
rivet bodies. No matter what work thickness (within the
grip range of the rivet) you are setting this rivet in, the
mandrel locking feature will lock the mandrel in the same
position and that is flush with the flange. This happens
for the following reason.
into the mandrel diameter at a depth to determine the
tensile strength of the mandrel.
No matter what the work thickness is, the locking
skirt will travel to the special nosepiece. The nosepiece
will flair out the locking skirt into the inside wall of
the rivet body and the mandrel will break at the predetermined
tensile groove.
The multiple grooves on the mandrel shank, are
there to prevent the pulling jaws of the setting tool from
slipping. Some setting tools use two piece pulling jaws
and other tools use a three piece pulling jaws. In either
case, the theory is the same. The pulling jaws have
grooves that contact the grooves of the shank diameter
LOCKING SKIRT
The mandrel has a locking skirt. When the mandrel
is being pulled by the setting tool to set the rivet,
the locking shirt moves in the direction of the special
nosepiece that is mounted on the setting tool.
ENGAGES LOCKING SKIRT
of the mandrel. The pulling jaws ride on a 10 degree
angle that is in the jaw housing and the jaws also have a
10 degree angle. As the grooves of the jaws contact the
grooves of the mandrel, the jaws will grip the mandrel.
As the setting tool pulls the jaws, the jaws start to lock
on the grooves of the mandrel and the jaws start to slide
down the 10 degree angle forcing the jaws deeper into
the grooves of the mandrel. The harder the setting tool
pulls the mandrel, the deeper the jaws press into the
grooves of the mandrel until the jaws have compressed
themselves as deep as they can into the mandrel.
The Interlock structural blind rivet looks the same
as a Monobolt structural blind rivet. The only difference
between the two is that the Interlock has an internal
locking grooves that lock the remaining mandrel in the set
rivet. The Interlock can be set with a standard nosepiece,
it does not need a special type nosepiece.
ANTHONY Di MAIO