(b)
Do not loosen it to install the lockwire or the cotter pin.
(c)
If you did not align the slot in the nut or the hole in the bolt, tighten and aligned it. 1) Use no more than the maximum torque limit.
(d)
If this procedure did not align the parts, loosen the part one-half of a turn.
(e)
Tighten the part again.
(f)
When this procedure has no effect, use a new part.
E. Self-locking nuts
S 912-035-N00
(1) Free-turn locknuts (Fig. 202)
NOTE: See the paragraph on the Torque-Check for Reuse of the
____
Self-Locking Fasteners.
(a)
The free turn locknuts turn freely on the bolt or the stud, until they touch the mating surface.
(b)
Apply the necessary torque to operate the mechanism, that locks the nut.
(c)
The Figure 202 shows the necessary torque limits.
S 912-036-N00
(2) Prevailing-torque locknut
(a)
The prevailing-torque locknuts turn freely on the bolt or the stud, until the threads go into the lock part of the nut.
(b)
Then the bolt pushes the deformation of the nut and holds the nut.
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(c) Use the torque limits in the Figure 203, unless the nut is on a stud. 1) Then use the torque limits in the Figure 202.
NOTE: Self-locking heli-coils are equivalent to the
____ prevailing-torque locknuts. The Figure 203 shows the torque limits for the bolts in these heli-coils.
(d)
All locknuts must engage the threads of the bolt or the stud to lock correctly.
(e)
It is not necessary for the bolt or the stud to extend above the end of the locknut. 1) The chamfer, that is on the end of the locknut thread, does
not lock on the bolt or the stud.
F. Machine Thread Plug With a Preformed Packing Seal (MS9015) and the Tube-Boss Nipple (MS9193 or Similar)
S 912-037-N00
CAUTION:_______DO NOT TIGHTEN MORE THAN THE LIMIT. THIS TORQUE WILL CAUSE
DAMAGE TO THE THREADS.
(1)
In the Figure 204, the torque limits come from the strength of a
cast aluminum or a cast magnesium.
(a) You can use these torque limits in stronger materials.
G.
PWA Flexible Fittings and Sealastic-Type Fittings (Fig. 205)
S 912-038-N00
(1)
The container has a mark for identification of the material and part number of each packing.
S 912-039-N00
(2)
The procedure uses the standards that follow:
(a)
AMS 7260 synthetic-rubber, 70-80 durometer A, packings for fuel seals.
(b)
PWA 401 fluorocarbon rubber, 70-77 durometer C (95-100 durometer A), for oil, air, or water seals. 1) Do not use the fluorocarbon rubber at a temperature, that
is more than 450°F (232°C).
S 912-040-N00
(3)
Assemble the two types of flexible fittings (AMM 70-24-01/201).
(4)
Refer to the Figure 205 to tighten the tube-coupling nut.
S 912-042-N00
(5)
The rubber in these flexible fittings will have less thread torque
after some time.
S 912-041-N00
(a) You can prevent this as follows:
1) Tighten the part to the torque limits.
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INCH DIMENSION THREAD* TORQUE, POUND-INCHES TORQUE, NEWTON-METERS
MIN MAX OIL LUBRICATED MIN MAX LUBRICATED ANTISEIZE MIN MAX LUBRICATED OIL MIN MAX LUBRICATED ANTISEIZE
0.112 -40 6-7 5-6 0.678- 0.791 0.565- 0.678
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