Piper Cherokee Six - Page 34

PIPER CHEROKEE SIX SERVICE MANUAL
TABLE
II-11.
RECOMMENDED
NUT
TORQUES
TORQUES: The importance of correct
application cannot be overemphasized. Undertorque
can result in
unnecessary wear of nuts
and bolts as well as the parts they are holding
together. When insufficient pressures
are applied,
uneven loads will be transmitted
throughout
the assembly which may
result in excessive wear
or
premature
failure due to fatigue. Overtorque can be
equally damaging because of failure of a bolt
or nut from
overstressing the thread areas. The following procedures should be followed to assure that the correct torque is
applied:
I. Torque (self-locking fasteners) - Add the friction torque from Chart A for sizes 8 through 7: 16 to
the recommended torque from Chart B to get the final torque. This would be the actual reading on
the torque wrench.
2. Torque (castellated and non-self-locking nuts) - Use only the torque given in Chart B. Unless
otherwise specified. when castellated nuts are used with a cotter pin on moving joints. do not torque
the nut. Turn the nut onto the bolt until proper grip is established and alignment with the cotter pin
hole is achieved. Then install the cotter pin.
GENERAL
REQUIREMENTS:
I. Calibrate the torque wrench periodically to assure accuracy: recheck frequently.
2. Ascertain that the
bolt and nut threads are clean and dry
(unless otherwise specified by the
manufacturer).
If the bolt or nut is specified
to be lubricated prior to tightening. the torque
range
should
be reduced
50 percent.
3. Use a bolt length long enough
to prevent bearing loads on the threads.
The complete chamfer or end
radius of the bolt or screw must extend through the nut.
4. Unique torques
specified in the text of this manual
supersede the torques given in Charts A and
B
5. Refer to
the latest revision of Lycoming SSP 1776
for torques on parts used on Lycoming engines
6. A maximum of
two AN960 washers may
be added under the
bolt heads or nuts
to correct for
variations
in material
thickness within
the tolerances
permitted.
7.
Limitations of the use of self-locking nuts.
bolts and screws including fasteners with
non-metallic
inserts are as follows:
A. Fasteners
incorporating self-locking
devices shall not
be reused if they can
be run up using only
fingers. They
may be reused if hand tools are required
to run them up. providing there is
no
obvious damage to the self-locking device prior to installation.
B. Bolts 5/16 inch diameter and over
with cotter pin holes may be used with
self-lockine nuts.
Nuts with
non-metallic locking
devices may be used
in this application
only ifthe boits are
tree
from burrs around the cotter pin hole.
C.
Do not use self-locking nuts at joints
which subject either the nut or the bolt
to rotation.
D. Never tap
or rethread self-locking
fasteners. Do not
use nuts. bolts or
screws with damaged
threads or rough ends.
Revised:
11/4/83
HANDLING
AND
SERVICING
1B10