Figure 2-35.Typical turnbuckle assembly.
and the other has left-hand threads, The barrel has
matching right- and left-hand threads internally. The
end of the barrel, with left-hand threads inside, can
usually be identified by either a groove or knurl
around the end of the barrel. Barrels and terminals
are available in both long and short lengths.
When you install a turnbuckle in a control system,
it is necessary to screw both of the terminals an equal
number of turns into the turnbuckle barrel. It is also
essential that all turnbuckle terminals be screwed into
the barrel at least until not more than three threads are
On initial installation, the turnbuckle
terminals should not be screwed inside the turnbuckle
barrel more than four threads. Figure 2-36 shows
turnbuckle thread tolerances.
After a turnbuckle is properly adjusted, it must be
safetied. There are several methods of safetying
turnbuckles. However, only two methods have been
adopted as standard procedures by the services.
These methods are discussed later in this chapter.
Adjustable Connector Links
An adjustable connector link consists of two or
three metal strips with holes so arranged that they
may be matched and secured with a clevis bolt to
adjust the length of the connector. They are installed
in cable assemblies for the purpose of making major
adjustments in cable length and to compensate for
cable stretch. Adjustable connector links are usually
used in very long cable assemblies.
Fairleads (rubstrips), grommets, pressure seals,
and pulleys are all types of cable guides. They are
used to protect control cables by preventing the cables
Figure 2-36.Turnbuckle tolerances.