North&Wing&S,LSA&Maintenance&Manual&
Model:&Sport&X2&582&
Issue 3.2
Printed: July 16 2017
Page 15
2.1.9
&
Torque Specifications and Securing
Before any fastener is torqued to specifications, it is important to assure at least one full thread
of the bolt will extend beyond the nut when tightened. If the nut does not extend at least that
far, the bolt thread itself may fail if tightened to specifications.
Not all bolt connections have specific torque requirements. There are three basic types of
bolt/nut connections that are addressed in the table below:
1.
!
Normal bolt/nut fasteners
2.
!
Nylock fasteners
3.
!
Castle nut fasteners
Normal bolt/nut fasteners will have torque specifications listed in the table below.
Nylock nuts are used for many applications. Some of those applications do not require
specific torque values while others do. For those applications where the bolt is exposed to
only shear forces, the nut should be tightened until there is no free play in the connection, or
all gap is eliminated between the nut and the fixtures being bolted together, then tightened
another quarter to half turn. These applications are referred to as “Snug” connections in this
manual. The limiting factor in the tightening of most Nylock applications on tubing is to avoid
distorting the tubing circular shape. For those applications where significant torque should
be used, a recommended torque is specified in the table below.
Castle nut fasteners are used for applications where the bolt is exposed only to shear stresses
and does not experience any longitudinal tensile stresses. The purpose of the castle nut is to
allow easy assembly and disassembly without the need for tools. Castle nuts must be secured
in place with a safety pin or ring of any appropriate design. For these fasteners some gap
between the bolt or nut under-side surface and the material being fastened is acceptable but
should not be excessive. That is, the nut should be tightened to remove all visible gap and
then adjusted to the nearest hole alignment for the safety pin. These types of attachments are
referred to in this manual as simply “Secured” as opposed to “Torqued” or “Snug”.
Some fasteners must be secured from loosening using either safety wire, ring safeties, or pin
safeties. The table below indicates which type of fastener should be used in each application,
the type of safety recommended for each where applicable, and the associated torque where
appropriate.