Singer Centurion 121D200A User manual
1
SERVICE
MANUAL
SINGER
Sewing
Machine
121D200A
Copyright
®
1976
The
Singer
Company
Aii
Rights
Reserved
Throughout
the
World
*A
Trademark
of
THE
SiNGER
COMPANY
Form
21624
(876)
Printed
In
U.S.A.
From the library of: Superior Sewing Machine & Supply LLC
L.
LUBRICATION
Moving
parts
have
either
permanently
sealed
pre-lubricated
ball
or
needle
bearings
or
oil
Impregnated
bushings
which
require
no
manual
lubrication.
The
following
exceptions
are:
HOOK
An oil
reservoir
supplies
oil
to
the
sewing
hook
race
and
Is filled
through
the
oil
cup
as
shown,
until
the
word
"FULL"
Is
seen
In
the
Indicator
window.
Check
oil level
at
Indicator
window
dally
before
starting
machine.
As oil level
decreases,
red
arrow
will
appear
(Fig. A).
0
Red
Arrow
Empty
(
H-
FIG.
A
From the library of: Superior Sewing Machine & Supply LLC
TO
TEST
HOOK
LUBRICATION
Thread
machine
and
sew
3
yards
of
scrap
material.
Pay
no
attention
to
stitch
quality
or
amount
of oil
at
this
time.
Remove
material
and
bed
slide.
Run
machine
approximately
one
minute
to
establish
a,uniform
oil flow.
Without
stopping
machine,
hold a
piece
of
paper
in
place
under
hook
for
10
seconds.
Remove
paper
and
compare
oil
pattern
with
Fig. B
for
proper
oil flow.
•••
, " • # •
♦
•
FIG.
B
If
there
is
no
trace
of oil
or
an
excess,
adjustment
should
be
made
with
the
oil
metering
screw,
in
order
to
gain
access
to
oil
metering
screw,
the
hook
should
be
in
position
as
shown
in Fig. C. Turn oil metering
screw
clockwise
for
more
oil
and
counterclockwise
for
less
(Fig. D). Normal
setting
is
made
by
turning
metering
screw
to maximum in position
and
backing
out
2-1/2
turns.
Less
than
2-112
turns
may
be
required
for long
continuous
runs.
FIG.
C
Oil
Metering
Screw
Hook
Shaft
Bushing
Oil
Filter
More
Oil
FIG.
D
Oil
Metering
Screw
Less
Oil
From the library of: Superior Sewing Machine & Supply LLC
Ifoil flow is not satisfactory, remove hook assembly and oil filter. Check filter. Oil wick
should
be
replaced
whenever
it
has
become
clogged
with lint or dirt. An
excess
of oil
sometimes
indicates
that
the
filter
wick
has
become
detached
from
the
screw
or
the
screw
is not
securely
tightened.
Inspect
all oil
passages
to
see
they have not
become
clogged.
Oil
Filter
(S)
Hook
Assembly
From the library of: Superior Sewing Machine & Supply LLC
MACHINE
THREADING
1.
Move
needle
to
highest
point
2.
Lead
thread
from
thread
stand
through
thread
post
atop
machine
arm
3.
Through
3
eyelets
of
thread
guard
4.
Units
with
U.T.T.,
through
pretensioner
5.
Down
through
thread
retainer
6.
Into
and
around
tension
assembly
7.
Over
check
spring
and
under
slack
thread
regulator
8.
Up
to
and
through
thread
retainer
and
take-up
eyelet
9.
Down
through
thread
retainers
(2)
10.
Through
needle
bar
thread
guide
11.
Through
needle
eye
from
left
to
right
From the library of: Superior Sewing Machine & Supply LLC
STITCH
LENGTH
The
stitch
length
can
be
regulated
while
the
machine
\s^'m
operation.
To
obtain
the
desired
stitch
length
In
forward
feed,
turn
regulating
thumb
screw
on
oil
pan
"In"
(coun
terclockwise)
for
more
stitches
per
Inch,
and
"out"
(clockwise)
for
less
(Fig. B).
To
adjust
the
stitch
length
for
reverse
feed.
It Is
necessary
that
the
reverse
stopping
block
be
properly
positioned.
This
Is
done
by
loosening
the
lock
screw
In
the
stopping
block
and
sliding
the
slide
block
up
or
down
to
the
desired
stitch
length.
The
locking
screw
must
then
be
retlghtened
(Fig. A).
Forward
I
Reverse
-0
Locking
Screw
FIG.
A
PRESSER
FOOT
PRESSURE
The
pressure
on
the
material
should
be
as
light
as
possible
while
still
sufficient
to
ensure
correct
feed
ing.
There
are
two
regulating
screws
that
control
the
presser
foot
pressure.
One
atop
the
arm
and
one
at
the
rear
of
the
machine.
The
one
atop
the
arm
Is
the
major
control,
normally
adjusted
prior
to
long
pro
duction
runs
or
new
applications.
For
day-by-day
casual
adjustments,
the
regulating
screw
at
the
rear
Is
used,
screwing
In
for
less
pressure
and
unscrew
ing
for
more
pressure.
When
this
rear
screw
Is
unscrewed
all
the
way
out.
It
disengages;
only
then
can
the
top
screw
be
applied,
and
It
serves
as
the
sole
control
until
the
rear
screw
Is
again
turned
In
ward
(Fig.
C).
Less
FIG.
B
Regulating
Screw
B
when
Screw
A
is
Disengaged
Regulating
Screw
A
From the library of: Superior Sewing Machine & Supply LLC
HOOK
TIMING
Proper
clearance
between
needle
and
hook
point, re
quires
that
the
point
of
the
hook
shouid
pass
the
nee-
die
as
closely
as
possible
without striking or
deflect
ing it.
There
shouid
be
.003
-
.005
clearance
bet
ween
the
two
(Fig. A).
To
adjust
clearance,
loosen
bushing
set
screw
(Fig.
B). With
screwdriver
placed
as
shown
move
entire
hook
and
bushing
(Fig. C).
Tighten
bushing
set
screw.
Hook
Bushing
Set
Screw
FIG.
B
Insure
that
the
needle
guard
prevents
the
needle
from
contacting
the
hook
point
at
any
time. If
large
needles
are
to
be
used
it
may
be
necessary
to
string
the
needle
guard
back
to allow
hook
point
closer
to
needle
(Fig. D).
6
.003
•
.005
Rat
of
Hook
Point
To
Needle
FIG.
A
FIG.
C
Needle
Guard
FIG.
D
From the library of: Superior Sewing Machine & Supply LLC
HOOK
TIMING
CONT'D
Reset
position
finger
so
there
is
.018
-
.022
thread
clearance
between
finger
and
basket
(Fig. E).
^.018"
-
.022"
FIG.
E
Loosen
hook
set
screws.
Turn
hand
wheel
in
direction
of
rotation
until
needle
bar
is
on
the
rise
stroke,
and
the
lower
mark
is
aligned
with
the
needle
bar
height
indicator.
Set
hook
point
to
the
center
line
of
the
needle
(Fig. F).
Tighten
hook
set
screws.
Needle
Bar
Height
indicator
FIG.
F
Hook
Point
to
Centeriine
of
Needle
From the library of: Superior Sewing Machine & Supply LLC
TIMING
FEED
LIFTING
SHAFT
TO
ARM
SHAFT
Manually
rotate
arm
shaft
until
timing
mark
on
counterbalance
aligns
with
timing
mark
on
take-up
stud
connecting
link (Fig. A).
0
Timing
Marks
FIG.
A
Loosen
bed
shaft
timing
belt
pulley
set
screws
(Fig. B).
Hold
pulley
stationary
and
rotate
bed
shaft
until
timing
mark
at
feed
bar
end
of
shaft
aligns
with
timing
mark
on
casting
(Fig. C).
Timing
marks
alignment
in Fig. A
and
Fig. C
must
occur
simultaneously.
Tighten
pulley
set
screws.
Set
®
Screw
(2)
ry
n
FIG.
B
TO
]
Q) ®
Timing
Marks
FIG.
C
8
From the library of: Superior Sewing Machine & Supply LLC
FEED
DOG
SETTING
Centrally locate feed dog in throat plate slots. Feed dog must not make contact with
throat
plate,
as
noted. Align by loosening
feed
dog
screws.
Then
retighten
screws
Fig. A.
Feed
Dog
No
Contact
FIG.
A
LATERAL
SETTING: Loosen pinch screw infeed bar crank
(Fig.
B).Shift feed bar
as
re
quired. Ensure that feed bar does not contact position finger.Tighten pinch screw and
check
axial play at pendant link. Adjust feed lifting shaft to minimize play.
Leveling
Eccentric
Feed
Bar
Crank
Pinch
Screw
Height
Eccentric
and
Locking
Nut
FIG.
B
9
Leveling
Eccentric
Set
Screws
From the library of: Superior Sewing Machine & Supply LLC
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