TM-9-2920-242-35
STARTER, ENGINE ELECTRICAL, ASSEMBLY MODEL 1113943, 1113904 AND 1113944
TECHNICAL MANUAL; DIRECT SUPPORT, GENERAL SUPPORT AND DEPOT MAINTENANCE INCLUDING REPAIR PARTS
SEPTEMBER 1964
TM-9-2920-242-35 - Page 38 of 110
(2)
(3)
tator against limits specified in wear
limits (par. 41f) and undercut mica ((2)
below) if refinished commutator is with-
in limits specified. Replace armature
if commutator does not conform to
measurements specified.
Undercutting mica. After resurfacing
the commutator, undercut mica to a
depth of 0.025 to 0.032 inch below the
surface of the commutator using a
power-driven undercutting tool (fig. 25).
If a power-driven tool is not available,
the mica may be undercut by hand as
shown in figure 26.
Note. Use care in undercutting. Do not
widen commutator slots by removing
metal from segments, and do not leave
thin edge of mica next to segments.
Figure 26 illustrates examples of good
and bad undercutting.
Polishing commutator. After the mica
has been undercut, remove all copper
and mica particles with compressed air.
Polish the commutator in a lathe with
No. 2/0 sandpaper (fig. 27) while the
armature is rotating at 1500 rpm. After
polishing the armature, check that the
diameter is within the limits specified
in wear limits (par. 41f).
e. Repair of Drive Clutch.
(1)
(2)
(3)
Smooth burs, nicks, and rough spots on
splines and pinion teeth using a fine
stone or crocus cloth dipped in dry
cleaning solvent.
Smooth rough spots, scoring, scratches,
and nicks on inside bore of sleeve bear-
ings and all surfaces of bronze bearings
using crocus cloth dipped in dry clean-
ing solvent.
Smooth minor rough spots, nicks, and
scratches on internal polished surface
of shell using a fine stone or crocus
cloth dipped in dry cleaning solvent.
If nicks and scratches cannot be re-
moved or surface cannot be restored
to original finish, replace the shell.
f. Repair of Lever Housing.
(1)
(2)
(3)
Smooth minor scratches, burs, and
nicks on machined surfaces of lever
housing using a fine mill file.
Repair damaged threads in housing.
Smooth minor rough spots, scoring,
scratches, and nicks on inside bore of
sleeve bearing using a fine stone or
crocus cloth dipped in dry cleaning sol-
vent.
FIGURE 27. POLISHING COMMUTATOR
WITH SANDPAPER.
g. Repair of Shift Lever, Shaft and Solenoid
Plunger.
(1) Smooth minor rough spots, scratches,
and nicks on clutch contact surfaces of
shift lever using a fine stone. Smooth
minor rough spots, scratches, and nicks
on lever shaft
(2) Repair damaged
h. Repair of Frame.
—
(1)
(2)
using a fine stone.
threads on plunger rod.
Smooth minor scratches, burs, and nicks
on machined surfaces of frame using a
fine mill file.
Repair damaged threads in frame. Re-
pair damaged threads on field coil ter-
minal stud.
29
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