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 TM 55-1905-222-14
6-23
REPAIR PROPELLER AND PROPELLER SHAFT (Continued).
until metal is below 250 (121C), after
F
which air-cooling is permissible. During all
preheating, welding, or stress relieving,
the propeller should be well supported in
order to avoid sagging and distortion.
Repairs, particularly to heavier sections of
the propeller, should be performed with
care in order to avoid thermal cracks or
tears due to shrinkage stresses which can
be imposed on the base metal.
2. REPAIR PROPELLER SHAFT.
a. Pitted Shafting. Cases of severe pitting in
outboard shafting, resulting from damaged
or porous covering, should be reported to
the appropriate authority who will decide
whether the shaft is suitable for further
service. If the pitted shafting is approved
for reconditioning, the sharp edges of the
pits should be well rounded by grinding
and the corroded areas should be dressed
down to the solid metal surface. Ground
out pits and corroded areas, if extensive
and of shallow depth, should be filled with
approved cavity build-up material. Pits and
corroded areas beyond allowable depth
should be build-up by welding and covered
with a protective rubber or plastic material.
b. Vibrations . If objectionable vibrations
exist, the shafting sections should be
removed and checked for straightness.
Dial indicator runouts of shafting ends,
measured at the propeller or coupling
tapers, should total less than 0.003 inch
(0.0015-inch eccentricity), which should
prevent excitation of the first-order
vibrations (one vibration per shaft
revolution). Runouts in excess of
6-127
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