Singer 251-2 - Arm Shaft Replacement; Replacing the Arm Shaft

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44
THE
ARM
SHAFT
(continued)
Fig.
70.
Replacing
the
Arm
Shaft
REPLACEMENT-
(See
Fig.
70)
CAUTION:
Make
certain
that
the
OIL-REMOVING
WICK ASSEMBLY
is
out
of
the
machine.
1.
Insert
the
machine-pulley-end
of
the
arm
shaft
into
the
arm
shoft
bushing
at
the
head
of
the
machine
arm.
2.
Make
certain
that
the
needle
bar
crank
is
turned
to
the
position
shown
in
Fig.
69,
clearing
the
three
wick
loops
in
holder
W4.
3.
While
still
holding
the
bevel
gears
at
S3
in
mesh,
with
a
screwdriver,
as
shown
in
Fig.
70,
push
the
arm
shaft
X4
straight
through
the
machine
arm,
the
feed
eccentric
U4
and
the
feed-eccentric-and-
bevel-gear
X3,
Fig.
70.
(A
light
tapping
with
the
palm
of
the
hand,
against
the
needle
bar
crank
end,
may
be
required.)
4.
Replace
machine
pulley
so
that
the
two
set
screws
T4
will
locate
over
the
two
grooves
V4
on
the
shaft
and
securely
tighten
set
screws
T4.
5.
Replace
and
tighten
the
arm
shaft
screw
R4
sufficiently
to
remove
all
end
play
of
the
shaft
without
binding.
Test
the
arm
shaft
for
freedom
in
rotation.
6.
Move
bevel
gear
X3
toward
machine
pulley
and
securely
tighten
feed
timing
screw
Y.
7.
Place
the
first
finger
of
one
hand
on
one
side
of
the
arm
shaft
and
the
first
finger
of
the
other
hand
on
the
other
side
of
the
arm
shaft
so
that
both
fingers
contact
the
bevel
gear
(on
vertical
shaft)
that
mates
with
the
gear
X3.
Feel
for
slight
backlash.
If
there
is
no
backlash,
loosen
timing
screw
Y
and
set
screw
0.
Lightly
tap
gear
X3
away
from
mating
gear
until
there
is
just
a
slight
amount
of
backlash.
Then
securely
tighten
timing
screw
Y
and
the
set
screws
in
gear
X3.
Re-
check
the
backlash.
8.
Using
a
screwdriver,
as
shown
in
Fig.
70,
move
feed
eccentric
U4
as
close
as
possible
to
the
con-
necting
rod
A2,
Fig.
70
and
tighten
the
timing
screw
and
two
set
screws
in
eccentric
U4.
9.
Check
the
adjustment
and
timing
of
parts
dis-
turbed
and
correct
where
necessary,
according
to
the
instructions
on
pages
18
through
2.S.
10.
Replace
the
oil-removing
wick
assembly,
as
in-
structed
on
pages
39
and
41.
11.
Replace
thread
take-up,
as
instructed
on
page
35.
12.
Replace
presser
bar
and
presser
foot,
as
in-
structed
on
page
33.
13.
Replace
the
upper
needle
bar
bushing
and
the
needle
bar,
as
instructed
on
page
33.
14.
Replace
thread
take-up
oil
guard
W2,
Fig. 54,
page
36.
15.
Replace
arms
side
shield
and
wick,
as
instructed
on
page
36.
16.
Replace
the
oil
lead
beneath
the
arm
top
cover.
17.
Reploce
the
arm
top
cover
and
tighten
its
four
screws.
18.
Replace
the
face
plate
and
tighten
its
four
screws,
as
instructed
on
page
18.