TABLE II-II. 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:
1. Torque (self-locking fasteners) Add the friction torque from Table A for sizes 8 through 7/16" to the
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:
1. 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 Tables 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-locking nuts. Nuts with
non-metallic locking devices may be used in this application only if the bolts are free 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.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
HANDLING AND SERV I C I N G
1B4
