Recommended Nut Torques - Piper PA-24 Comanche Service Manual

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PIPER COMANCHE SERVICE MANt:AL
TABLE II-II.
RECOM~1E~DED
xur
TORQUES
(I~CH-POl:'DS)
Torque (self-locking fasteners) - Add thefriction torquefrom Chart A for sizes 8through
7
I{ito the
recommended torque from Chart B to get the final torque. This would be the actual reading on the
torque wrench.
Torque (castellated and non-self-locking nuts) - Use only the torque given in Chart B. Unless other-
\\ ise specified. \\ hen 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.
b.
TORQl'E
REQURE~E~TS:
The torque
values
given in the following tables are recommended for all
airframe installation procedures where torquing is required. unless otherwise noted in sections where other
values are stipulated.
The importance of correct application cannot be overemphasized. Undertorque can result in unnecessary
wear of nub 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 over-
stressing the threaded areas. The following procedures should be followed to assure that the correct torque is
applied:
a.
GE~ERAl REQl'IRE~ESTS:
a.
b.
c.
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d.
e.
f.
g.
Calibrate the torque wrench periodically to assure accuracy; recheck frequently.
Ascertain that the bolt and nut threads are clean and dry (unless otherwise specified by the manu-
facturer). If the bolt or nut is specified to be lubricated prior to tightening. the torque range should
be reduced 50 percent.
lse a bolt length long enough to prevent bearing loads on the threads. The complete chamfer orend
radius of the bolt or screw must extend through the nut.
Inique torques specified in the text of this manual supersede the torques given in Charts A and B.
Refer to the latest revision of Lycoming SSP 1776 for torques on parts used on Lycoming engines.
A maximum of two A'960 washers rnav be added under the bolt heads or nuts to correct for
variations in material thickness within th~ tolerances permitted.
Limitations of the use of self-locking nuts. bolts and screws including fasteners with non-metallic
inserts are as follows:
I. 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.
Bolts 5 16 inch diameter and over with cotter pin holes may be used with self-locking nuts.
;\uts with non-metallic locking devices may be used in this application only if the bolts are
free from burrs around the cotter pin hole.
J
Do not use self-locking nuts at joints which subject either the nut or the bolt to rotation.
4. 'ever tap or rethread self-locking: fasteners. Do not use nuts. bolts or screws with damaged
threads or rough ends.
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RE\'ISED: 11/1/82
IB19
HANDLING AND SERVICISG