Jo-Bolts with hexagon-shaped heads (hex type) are made
of an alloy steel.
Their sleeves are annealed and corrosion
resistant. In addition, the bolt and sleeve are cadmium plated.
Millable hex-type. The millable hex-type Jo-Bolt usually takes the
same size countersink or dimple used for the corresponding size
rivet. The bolt is made of alloy steel and the sleeve of corrosion-
Both are cadmium plated.
The nut is made of an
aluminum alloy, and, after installation, the nut head is milled flush.
The oversize-type Jo-Bolt is used in special
applications where the hole size has been exceeded and standard Jo-
Bolts cannot be used. The head size and material specifications are
the same as for the flush and hex types except for the size of the
nut shank diameter.
The majority of aircraft rivets are made of an aluminum alloy. Other
metals used are steel and copper.
Rivets used in Army aircraft are
divided into two main groups: solid-shank and blind rivets.
solid-shank rivets are divided into universal- and countersunk-head
Countersunk rivets are used for a flush fit and for
aerodynamic surfaces; universal-head rivets are used on exterior and
interior locations and when clearances for adjacent members are not
Blind rivets are used where one side of a riveted
structure is not accessible or room for a bucking bar is not
These rivets require special tools and installation and
Blind rivets include friction and mechanical
The head styles commonly used are the protruding and
The Hi-Shear rivet consists of a pin and a
collar. Access to both sides of the held material is required to use
The pin is headed on one end and grooved about the
circumference at the other.
The collar is swaged onto the grooved
The rivnut unit is composed of a rivnut and a screw, either
attachment or plug type.
They are used in blind locations, such as
leading edges for deicer boot installation.
Keyed rivnuts are used
as nut plates and unkeyed ones are used for blind riveting where
torque loads are imposed. Closed-end rivnuts are used where a sealed
installation is required.
The special-purpose bolts in general use in Army aviation are
Huck lock bolts and Jo-Bolts. The most commonly used Huck lock
bolts are the pull, stump, and blind types. The pull type is
mainly used in primary and secondary aircraft structure. The