Recommended Nut Torques - Piper PA-44-180 SEMINOLE Maintenance Manual

TO R Q U E S : The importance of correct application can not 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 threaded areas. The following
procedures should be followed to assure that the correct torque is applied:
1. 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. To determine
friction drag torque for sizes 1/2 through 1 1/4, turn the nut fully on to the bolt
and determine the torque required to turn the nut. Add this friction drag torque
to the torque given in Chart "B".
2. 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.
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 manufacturers.) If the bolt or nut is required to be lubricated
prior to tightening, the torque range should be reduced 50 percent.
3. Use a bolt 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 supercede the torques
given in Charts "A" and "B".
5. Refer o the latest revision of Lycoming Service Table Limits, SSP1776, for
torques on parts used on Lycoming engines.
6. A maximum of two AN960 washers may be added under bolt heads or nuts to
correct for variations in material thickness within the tolerances permitted.
7. Self-Locking Fasteners - 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 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 bolt
to rotate.
D. Never tap or rethread self-locking fasteners. Do not use nuts, bolts or
screws with damaged threads or rough ends.
BOLT
SIZE
8 (course thread)
10
1/4
5/16
3/8
7/16
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
CHART 9102. RECOMMENDED NUT TORQUES
CHART A
FRICTION DRAG
TORQUE (IN. -LB.)
15
18
30
60
80
100
4A21
CHART B
COARSE THREAD SERIES
BOLTS
Steel Tension
AN 3 THROUGH AN 20
AN 42 THROUGH AN 49
AN 73 THROUGH AN 81
AN 173 THROUGH AN 186
MS 20033 THROUGH MS 20046
MS 20073
MS 20074
AN 509 NK9
MS 24694
AN 525 NK525
MS 27039
NUTS
Steel Tension
AN 310
AN 315
AN 363
AN 365
NAS 1021
MS 17825
MS 21045
MS 20365
MS 20500
NAS 679
Nut-bolt Torque Limits
size in-lbs.
Min. Max.
8-32 12 15
10-24 20 25
1/4-20 40 50
5/16-18 80 90
3/8-16 160 185
7/16-14 235 255
1/2-13 400 480
9/16-12 500 700
5/8-11 700 900
3/4-10 1,150 1,600
7/8-9 2,200 3,000
1-8 3,700 5,000
1-1/8-8 5,500 6,500
1-1/4-8 6,500 8,000
Revised: May 15, 1989
Steel Shear
AN 320
AN 364
NAS 1022
MS 17826
MS 20364
Torque Limits
in-lbs.
Min. Max.
7 9
12 15
25 30
48 55
95 110
140 155
240 290
300 420
420 540
700 950
1,300 1,800
2,200 3,000
3,300 4,000
4,000 5,000
9 1 - 0 1 - 0 1
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