Singer 331Kl User manual

Form ·K6542
(365)
SINGER.
SERVICE MANUAL
*A Trademark of THE SINGER COMPANY
331Kl and 331K4
THE SINCER COMPANY
© 1962 by The Singer Company
Copyright Under International ·Copyright Union
All Rights Reserved under Inter-American Copyright Union
Printed in Great Britain

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
2
CONTENTS
PAGE
DESCRIPTION
.•.•••••••.•.•••••••.••.•.•••••
3
LUBRICATION
AND CLEANING
•••••••••••••••••
4
INFORMATION
FOR
OPERATION
•••••••••••••
4-11
PAGE
ADJUSTMENTS
••••.•••••••••••••••••••••
12-16
PARTS
LIST
.•.•••••••••••••••••••••••••••••
17
INDEX
Bed
Slide (Slide Plate)
••••••••.•••••••••••.•.•
8
Belt Guard
•••••.•••••.•••••••.••••.••••••.•
3
Bobbin and Bobbin
Case
••••••••••.••••••••.
7-9
Bobbin
Winder
•••••••••••••.••••••.•••••••
4, 7
Capacity
of
Machine
•..•.•••••.•.••..•••.•
3,
12
Centralizing Feed Dog
••••.••••••••••••••••••
16
Common
Causes
of
Stitching Troubles
••••••••••••
5
Description
of
Oil
••.•.•.•••..•.••••.••••••••
4
Dimensions
of
Machine
••.••••••.••.•••••••••••
3
Drawing Up Bobbin Thread
•.••••••••••••••••••
8
Feed Dog
••••••••.•••••.•••••••••••••••
1
5,
16
Feed,
Reverse
••••••••.•••••.••••••••••
;
••
3,
10
Feed Timing
•••••••••••••••••.•••••••••••••
15
Graduated Stitch Indicator
••••••••••••••••••••
10
Knee
Lifter
•••••.••••••••.•••••••••••••••••••
3
Length
of
Stitch
••••••..••••..•••••.•.•.•••
3,
10
Light Fixture
••.•.•••••••••••••••••••••••••••
3
Link
Take-up
••••••••••.•••••••••••••••••••
3, 6
Lint, Removal
of
Excess
••.••••.••••••••••..•.••
4
Machine
Dimensions
•••••••••••••••••••••.••••
3
Machine Pulley
•••••.•••••••••••••••••••••
3,
11
Needles
••••••••••.•••.•.••••••••••••.••••••
5
Needle Bar
••••..•••••.••••••.•.•••••
3, 12, 13
Needle Setting
...•..••••••••••••••.•••••••••
5
Needle to Shuttle, Clearance
•••••••.••••••
13,
16
Perfect Stitch
••••••.••••••••.•••...••••••••••
8
Preparation
for
Sewing
..•••.••.••••••.•••.•••
8
Presser Bar
••••.•••••..•••••••
·
•••••.•••••••
12
Presser
Bar Guide Bracket
•••••••.•••••••••••
12
Presser
Foot
•••••••.••••••••.••••••.••
3, 12, 15
Pressure
of
Presser
Foot
•.••••••••••••••••.••
9,
15
Pulley
••••••••••••••••••••••••••••••••••
3,
11
Reverse
Feed
••••••••••••••.•••••••••••••
3,
10
Rotary
Tens
ion
••••••...••••..•••••••••••••
3, 9
Setting Up Machine
•••.•••••.••••••••••••••••
3
Shuttle
•••••••••••••••••••••••••••••••••
13,
14
Shuttle to Needle Clearance
•...•••••.•••••
13,
16
Specifications
•••.••.••••.••.••••..•••••••
3,
12
Speed
•••.••••••••••••••.•••••••••••••.••••
3
Starting to Sew
•••••...•••.•.••••••••••••
8,
11
Spillage, to Avoid
••••.•.•••.•..••••••••••••••
7
Stand
•••••••••••••••••••••••••.••••••••••••
3
Stitch Indicator
•••••••••••••••••••••••••.••
10
Stitch Length
•••••••••••••••••••••••••••••••
10
Stitch Type
•••••••••••••••••••••••••••••••••
3
Stitching Troubles,
Causes
of
••.••••••••••••••••
5
Stop Motion
••.•..•••••••••.••.••••••••••••
11
Table
•.••.••.•.••••••••••••••••••••••.•••••
3
Tacking
•••••.••••.••••••••••••••••••••••••
10
Take-up Lever
•••••••••••••••••••••.••••••
3, 6
Take-up Lever Guard
..••••.•••.••••••••••••••
3
Tension,
Check Spring
•.•••...•.•••••••••••••
1
4
Tension,
Threads
••.••••••••.•.•••••••••••••
8, 9
Thread
.•••••••••••••••••••.•.••••••••••••••
5
Threading, Bobbin Case
•••••••••••••••••••••••
7
Threading,
Upper
(Needle)
•••••••••••.••.•••••
6
Throat Plate
••••••••••••••••.••••••••••••
3,
16
Treated Material, Speed when Sewing
•••••••••••
3
Treadling Procedure
•••••••••••••.••••••••••
11
Turning a Corner
•.•••••••••.•••••••••••••••••
8
Twist
of
Thread
••••••.••.••••••••••••••••••••
5
Unwinder
••••••••••••••••.••••••••••••••••
3, 6
Upper Threading
••••••••.••••••••••••••.••••
6
Winder
(Bobbin)
•••••••••••••••••••••••••••
4, 7

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
DESCRIPTION
Machines
331K1
and
331K4 produce
top
quality,
single-needle, straight-line lock stitching
in
suits, shirts,
skirts
and
other
clothing.
MACHINE 331 K1:
Stitch Type #301.
Central bobbin.
Short
beak,
oscillating shuttle on horizontal axis.
Link
take-up.
Thread
take-up
lever
guard.
Drop
feed.
Hinged presser foot 161066.
Feed
dog
149603.
Throat
plate
26606.
Length
of
stitch controlled
by
regulator thumb screw
on front
of
machine arm.
Maximum stitch
length-5-1
/3 to the
inch.
Front, intermediate
and
rear
plain bearings.
Clamp
type
needle
bar.
Tapped
hole
and
seat
in
rear
of
arm provided for
mounting light fixture independently
of
presser
bar
lifting lever hinge screw.
Needle
bar
stroke
is
1.472 inches.
Clearance
under presser foot
is
5/16
inch.
Machine dimensions: Bed length
18-3/4
inches,
width
7
inches.
Belt guar,d 174112
available
on
order.
Knee lifter 139625 regularly supplied.
3
MACHINE 331K4:
Similar to
Machine
331
K1, with the following
exceptions:
Spring-biased, quick reversible
feed
mechanism
permits
operator
to
feed
work
backward
or
forward
at
will.
Solid presser foot 12144.
Feed
dog
149304. Throat
plate
12414.
INSTALLATION
Before placing the machine
in
its
cut-out on
table,
see
that
the four cushioning
pads
are
at
the four cor-
ners
of
the cut-out. Place the machine on these
pads.
SPEED
The maximum
speed
for these machines
is
2200
stitches
per
minute, according to the material sewn
and
the
type
of
work being done.
It
is
advisable
to
operate
these machines
at
a more
moderate
speed
the first few
days,
after
which they
can
be
operated
at
maximum
speed.
Reduce speed
of
machine when sewing closely
woven fabrics
or
treated
materials.
MACHINE
PULLEY
Machine pulley 139724 (solid discs,
balanced)
has
an
outside
diameter
of
belt
groove
of
2.90
inches
for
3/8
inch
V-belt. Effective
diameter
for
5/16
inch
round
leather
belt
is
2-5
/ 16 inches.
When
in
operation, the
top
of
the machine pulley
must
always
turn
over
toward
the
operator.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
LUBRICATION AND CLEANING
Use
SINGER* OIL, "TYPE B"
or
"TYPE
D".
Use
"TYPE
D"
OIL
when
an
oil
is
desired
which
will
produce
minimum stain
on
fabrics.
A machine in
continuous
use
should
be
oiled
fre-
quently.
Frequency
is
dependent
upon
the
speed
at
which the machine
is
operated
and
the
type
of
work
being
done.
Basically the machine needs
oiling
at
least
twice
each
working
day.
Before
starting
the machine,
at
the
beginning
of
the
day
and
again
after
the
midday
recess,
apply
a
few
drops
of
oil
at
each
of
the
oiling
points on the machine.
Arrows
indicate
oiling
points in
Figs. 2
through
5.
Never
attempt
to
oil
shuttle
race
(See
Fig.
S)through
holes in
throat
plate.
REMOVE
SCREW
AND
REMOVE
FACE
PLATE
4
BOBBIN WINDER LUBRICATION
Oil
bobbin
winder
occasionally
by
applying
a
few
drops
of
oil
to
oil
wick
in
bobbin
winder
frame,
as
instructed in
Fig.
11,
page
7.
CLEANING
Clean
out
all
lint
and
abrasive
matter
from
around
the shuttle
and
between
the
feed
rows on the
under-
side
of
the
throat
plate.
Close
all
covers
after
oiling
and
cleaning.
Wipe
off
excess
oil
from
surfaces
of
machine
that
may
come in
contact
with
material.
• •
Fig.
2.
Oiling
Points-Front
View
Fig. 4. Oiling beneath Machine
Bed
•
#S·~li.
(//r(F_,""·
:.".c:..=,.~'lff!!:,'t:'::::~;":·~::·:::~"=:::.~:.::;;,:;::::':"
\
'
'
Fig.
3.
Oiling
Points-Rear
View
Fig.
5.
Oiling
Points
behind
Face
Plate
and
in
Shuttle
Race

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
THREAD
On Machines of Class 331K, use only left twist
thread in the needle. Either right or left twist thread
can be used in the bobbin.
To determine the thread twist, hold the thread as
shown in Fig. 6. Then twirl the thread over toward you.
If the strands of the thread wind tighter, the thread is
left twist, if the strands unwind or separate, the thread
is right twist. Rough or uneven thread, or thread which
passes with difficulty through the eye of the needle,
will interfere with the successful use of the machine.
NEEDLES
The needle you select will have a very direct effect
on the quality, strength
and appearance of the stitch
produced
by the machine.
In selecting a needle size ... the eye must be large
enough to allow the thread you are using to pass
through freely without binding or chafing. A simple
test
is to thread a short length of thread through the
eye of the needle selected; hold the thread taut in a
vertical position.and twirl the
needle about the thread.
If the size is correct, the needle should slip down the
thread easily.
Needles for this machine
are of Catalog #2055
(16 x 87)
in Sizes 8 to 14, 16 to 19 and 21 to 25.
Orders for needles must specify the Quantity
required, the Size number, also the Catalog number.
For example:
"100 Size 16, Catalog #2055
(16 x 87) Needles"
For best results always use SINGER needles.
TO SET THE NEEDLE
Turn the machine pulley over toward you until the
needle bar moves to its highest point.
After loosening
needle clamping screw, remove old
needle and insert new needle UP into needle bar AS
FAR AS IT WILL GO, as instructed in Fig. 7.
The single continuous groove of the needle MUST
face away from the shuttle point (toward the left end
of the machine, as shown in Fig. 7) with eye of needle
directly in line with arm of machine.
Securely tighten
needle clamping screw.
5
HOLD THIS END
Fig. 6. How to Determine the Twist
VE TO
HEST POINT
T NEEDLE UP
AR AS POSSIBLE
TIGHTEN SCREW
Fig. 7. Setting the Needle
COMMON CAUSES OF STITCHING TROUBLES
Check needles often to make sure these defects are
not present ...
• Wrong needle for thread and material in use.
• Bent needle, clogged needle eye, or dirty
needle grooves may cause skipped stitches.
• Hook or bur~ on needle point may cause picking
or fraying of the material.
• Incorrect setting of needle.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
6
TAKE-UP
LEVER
~
MOVE
NEEDLE
BAR
TO HIGHEST POINT
Fig. 8. Upper Threading
UPPER
THREADING
NOJE:
Thread unwinder 225258
is
recommended for
use with these machines.
First,
turn the machine pulley
over
toward you
until
needle
is
at
its highest point, then
pass
the
needle
thread
from the unwinder through the threading points
in
the
order
shown
in
Fig. 8.
Pass the
thread
from left to right through
needle
eye.
Draw
about
two inches
of
thread
through the
eye
of
the
needle
with
which
to
start
sewing.
TO REMOVE
THE
BOBBIN
Turn
machine pulley
over
toward you
until
needle
thread
take-up lever
is
at
highest point,
as
shown
in
Fig.
8.
Reach beneqth
bed
of
machine with left hand
and
remove bobbin from shuttle body,
as
instructed
in
Fig.
9.
While latch
is
kept
open, bobbin
will
be
retained
in
bobbin case.
To
remove bobbin from bobbin case,
release
latch
and
turn the
open
end
of
bobbin
case
downward.
Bobbin
will
drop
out,
as
shown
in
Fig.
10.
""
.
RELEASE
LATCH
■
/4.
BOBBIN
~
DROPS OUT
Fig. 10. Removing Bobbin from Bobbin Case

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
TO WIND
THE
BOBBIN
(See "STOP MOTION
DEVICE"
for
treadle
machines on
page
11)
Bobbin winder should
be
fastened to
table
with its
driving pulley
approximately
1
/4
inch
in
front
of
the
machine belt. Bobbin winder driving pulley
will
then
make
firm
contact with machine belt when thumb latch
is
pressed down. Bobbin winder pulley
will
be
released
from contact with
belt
when sufficient
thread
has
been
wound upon the bobbin.
Place bobbin on spindle, pushing it on
as
far
as
it
will
go
and
pass
thread
through threading points,
as
shown
in
Fig. 11.
Wind
end
of
thread
around the bobbin a few times
in
the direction shown
in
Fig. 11. Press down on thumb
latch, pushing driving pulley
over
against
belt.
Start
the machine.
Bobbins can
be
wound while the machine
is
stitching.
TO
AVOID
SPILLAGE:
Regulate bobbin winder to
stop automatically when bobbin
is
wound
approx-
imately 1
/16
inch
short
of
bobbin
rim.
TO THREAD
THE
BOBBIN
CASE
Hold the bobbin so
that
the
thread
will
unwind
in
the
direction shown
in
Fig. 12.
Hold the bobbin
case
as
shown
in
Fig. 12
and
place
the bobbin into it.
Pull
the
thread
into the slot 1, Fig. 13
and
under the
tension spring
2,
Fig. 13.
Draw the
thread
into the delivery
eye
at
the
end
of
the tension spring,
as
shown
at
3, Fig. 14.
TO
REPLACE
THE
BOBBIN
CASE
After threading,
take
bobbin
case
by
latch
in
the
left hand.
Place
bobbin
case
on centre stud
of
shuttle
body
with position finger pointing
upward,
in
front·of notch
in
upper
plate
over
shuttle race,
as
shown
in
Fig. 15.
Release latch.
Press bobbin
case
back
until
latch catches groove
near
end
of
stud.
Allow
about
two inches
of
thread
to
hang
free.
7
NOTE-TIGHTEN
FOR
MORE THREAD
ON
BOBBIN
ACE
BOBBIN
ON
SPINDLE
. WIND THREAD
3.
PRESS
DOWN
Fig. 11. Winding the Bobbin
SLOT~
Fig. 12. Placing Bobbin in Bobbin Case
2. DRAW THREAD
DOWN AND
UNDER
SPRING
Fig._
13. Pulling the Thread into the Slot
·fig.
14. Drawing the Thread Under the Tension Spring
1. HOLDING LATCH,
REPLACE
BOBBIN
CASE
ON
STUD
2.
RELEASE
LATCH
3.
PRESS
BACK
Fig. 15. Bobbin Case Threaded and Replaced

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
8
Fig. 16.
Drawing
Up the Bobbin Thread
Fig. 17. Perfect
Stitch
Fig. 18. Too Tight Needle Thread Tension
Fig. 19. Too Loose Needle Thread Tension
TO PREPARE FOR SEWING
Hold slack end
of
needle
thread
loosely
and
turn
machine pulley
over
toward
you
until
needle
moves
down
and
up
again
to
its
highest point, catching bobbin
thread.
• Draw up
needle
thread;
bobbin
thread
will
come
up with
it
through hole
in
throat
plate,
as
shown
in
Fig. 16.
• Lay both
threads
back
under presser foot.
• Close the
bed
slide.
•
Always
keep the bed slide closed when the
machine
is
in
operation.
TO
START SEWING
• Move
take-up
lever to
top
of
its
stroke
as
shown
in
Fig. 8,
page
6.
• Place material
beneath
the presser foot. Lower
the presserfoot.
Start
to sew, turning the machine pulley
over
toward
you.
TO TURN A CORNER
• Stop the machine when
needle
is
rising but before
it
is out
of
the material.
• Raise the presser foot.
•
Turn
material for next line
of
stitching, using
needle
as
a pivot.
• Lower the presser foot.
• Resume sewing.
• Avoid aiding the machine
by
pulling the fabric,
lest you
damage
the needle. The machine
feeds
the
work without assistance.
TO REMOVE
THE
WORK
• Stop the machine with the
take-up
lever
at
top
of
its stroke.
• Raise the presser foot.
• Draw the work
toward
the
rear
until
it
is
clear
of
the needle.
• Cut the
threads
close to the goods.
• Lay the
threads
back
under the presser foot.
THREAD TENSION
For
ordinary stitching, tension on
needle
and
bob-
bin
threads
should
be
balanced with needle and
bobbin threads locked
in
centre of thickness of
material
as
shown
in
Fig. 17.
When there
is
too
much
tension on
needle
thread
and
not enough on bobbin
thread,
needle
thread
cannot
be
pulled down into material,
as
required. Poor stitching
results. Needle thread will lie on top
of
material
as
shown
in
Fig. 18.
When there
is
too
much
tension on bobbin
thread
and
not enough on
needle
thread,
you
get
the reverse
of
the condition shown
in
Fig. 18. The stitching
is
just
as
poor. The bobbin thread will lie on bottom of mate-
rial
as
shown
in
Fig. 19.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
REGULATION
BOBBIN THREAD TENSION:
For
average
sewing, tension on bobbin
thread
should
be
very
light.
To
regulate
tension on
bobbin
thread,
remove
the
bobbin
case
and
turn screw
in
tension spring,
as
in-
structed
in
Fig.
20
.
.
When
tension on
bobbin
thread
has
been
correctly
adjusted for ordinary stitching,
the required stitch
can usually
be
obtained
thereafter
to suit the work
in
process
by
varying
the tension on needle thread
only.
NEEDLE
THREAD TENSION: .
To
avoid accumulating excessive tension on
needle
thread,
first
obtain
correct tension on
bobbin
thread,
as
instructed
above.
Regulate needle thread tension
only
when
presser foot
is
down
(since
needle
thread
tension
is
automatically
released
when presser foot
is
raised}.
Tension on
needle
thread
should
be
just enough to
set stitch correctly
in
mate~ial.
Having
lowered
presser foot, turn thumb nut
at
the
front
of
tension discs either
over
toward
right
or
left,
as
required.
See
instructions
in
Fig. 21.
PRESSURE
OF
PRESSER
FOOT
ON
THE
MATERIAL:
The correct presser foot pressure helps
feed
the
work efficiently.
You
can
regulate
the amount
of
pres-
sure
exerted
by
the presser foot on the material
by
means
of
the thumb screw,
as
shown
in
Fil,,
22.
The pressure on the material should
be
as
light
as
possible, while sufficient to insure correct
feeding.
To
increase
the pressure turn the thumb screw
down-
ward.
To
reduce
the pressure turn this screw
upward.
The
pressure
is
correct when the work moves
steadily
and
smoothly without stalling.
9
Fig.
20.
Regulating Bobbin Thread Tension
Fig
..
21.
Regulating Needle Thread Tension
Fig.
22.
Regulating the Pressure on the Material

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
Fig.
23.
Regulating Length
of
Stitch
on
Machine
331Kl
2. TURN . '
1, \
THUMB ' \ i
1
1:
l
1
!
1
I \
i
1
i:1
l
SCREW
I FOR LONGER
//
j I
---~---
STITCH
'J,,/''
1
··---..
',
---
..:.L
✓
\ '
\
.
,
l \
I!
'O
\(
l.
DEPRESS
1
~
FOR
SHORTER
LEVER
//
STITCH
~-:l
·,
,==="I\\
l ,
,,._,
5
-.,,f4
;_)l
\
I!
,,~-:;~=-=--~
\
~-
C 3.
RELEASE
l
Ji~
~LEVER
:I
:t;
-~
Fig. 24. Regulating
Length
of
Stitch
on
Machine
331K4
Fig. 25. Reversing the Feeding Movement
on
Machine
331K4
10
REGULATION
LENGTH
OF
STITCH,
ON
MACHINE 331 K1:
The
length
of
stitch
is
regulated
by
moving the
pointer
in
the stitch indicator
plate
on the front
of
the
machine
as
instructed
in
Fig.
23.
When pointer
is
set
at
O
there can
be
no feeding
motion.
Maximum length
of
stitch
is
51/a stitches
per
inch.
Move pointer to desired length
of
stitch
and
firmly
tighten thumb screw.
LENGTH
OF
STITCH,
ON MACHINE 331K4: ,
Depress the feed-reversing lever slightly
and
turn
thumb screw over to the leftto lengthenthe stitch
or
over
to the right to shorten the stitch,
as
instructed
in
Fig.
24.
Thumb
screw
is
marked with numerals from
"O"
to
"5".
When thumb screw
is
set
at
"O"
feed
reversing lever
is
fixed
at
central position
and
there
can
be
no forward
or
reverse feeding.
When thumb screw
is
set
at
"5", machine
will
feed
at
maximum stitch length.
REVERSE
FEED,
ON
MACHINE 331K4:
(See instructions
in
Fig. 25)
Simply depress the feed-reversing lever
as
far
as
it
will
go.
Feeding
in
reverse continues only
as
long
as
lever
is
held
in
depressed
position.
Forward feeding
is
resumed upon
release
of
lever.
Direction
of
feed
can
be
reversed
at
any
point
in
a
seam while machine
is
in
operation, without disturbing
the work. Back tacking
is
therefore readily accom-
plished
and
ends
of
seams
are
easily fastened.
The
range
of
movement
of
feed
reversing lever
is
limited by the setting
of
thumb screw
as
instructed
above
under stitch length regulation.
When lever
is
released
it
will
rise to highest point
permitted
by
setting
of
thumb screw
and
machine
will
stitch forward
at
the
set
stitch length.
When lever
is
depressed
as
far
as
permitted
by
the
thumb screw setting, machine
will
feed
in
reverse
at
the
set
stitch length.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
THE STOP MOTION DEVICE
Machine 331K1 and 331K4 are regularly fitted
with solid disc (balanced) machine pulley 139724,
without stop motion device.
When required for treadle operation a machine may
be obtained, on specific order, with machine pulley
139725, including a stop motion device, as shown in
Fig. 26.
This device allows machine pulley to turn without
-turning arm shaft so that bobbins may' be wound and
correct treadling acquired without disturbing the
stitching mechanism.
To loosen the machine pulley, hold
pulley with left
hand and, with right hand, turn the stop motion screw
over toward you, as shown in Fig. 26.
TREADLING
To acquire correct treadling habits, loosen the
machine pulley, as instructed in Fig. 26 and place both
feet squc;:irely but comfortable upon treadle, as instruct-
ed in Fig. 27.
Turn machine pulley over toward you by hand and
at the same time, allow your feet to move freely and
lightly with motion of the treadle.
Continue to do this until a regular, easy movement is
acquired and you are able to stop and restart the
machine without the machine pulley turning in
the wrong direction.
Tighten the stop motion screw and practice sewing
until you have become accustomed to the necessary
motion
of hands and feet during the actual operation.
11
Fig. 26. Loosening Machine Pulley
Fig. 27. Position
of Feet Upon Treadle
NOTE: The instructions on the following pages are for Service Representatives.
To insure correct timing and avoid unnecessary repetition, these instructions should
be followed in the order given.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
SPECIFICATIONS
The following
gauge
distances should
be
of
help to
adjusters
of
these machines:
• Height
of
presser foot
above
throat
plate
5/16
inch.
• Distance from
throat
plate
seat
to
needle
stop
in
needle
bar
(needle
bar
at
lowest point),
1.004
inches.
•
Needle
bar
stroke
1.472
inches
• Rise
of
needle
bar
when point
of
shuttle
is
at
center
of
needle
(loop lift), .100
inch.
VARIATIONS: Certain conditions of sewing
may
necessitate slight variations from these settings.
\
~---
EA~·
..........
--::y._
r::._
=_
-:c.~'~,
B .
0
D
FOOT RESTING
FIRMLY
UPON
l,
THROAT
PLATE
\
~o
c::::-
CLEARANCE
C
Fig. 28. Checking Height
of
Presser Bar
12
TO
SET
THE
PRESSER
BAR
AT
THE
CORRECT
HEIGHT
PREPARATION:
Remove
face
plate
and
slide
plate.
Accumulation
of
lint, oil
and
dirt on presser foot
seat
on presser
bar
may
prevent
proper
seating
of
foot.
Clean this
area
before
checking
and
setting the
presser
bar.
CHECK:
1.
When
presser foot
is
raised with presser
bar
lifting
lever there should
be
a
5/16
inch
clearance
between
presser foot
and
throat
plate.
2.
When presser foot rests firmly upon
throat
plate
(with
feed
dog
below
throat
plate)
there
should
still
be
some
clearance
between
guide
bracket
A, Fig.
28
and
lifting
bracket
B,
as
shown
in
Fig.
28.
3. When presser foot
is
at
its highest poi'nt
and
needle
bar
is
at
its
lowest,
top
of
presser
foot should
clear
the
needle
thread
eyelet
C, Fig.
28
at
the lower
end
of
needle
bar.
SETTING:
• Release the presser
bar
lifting lever
D, Fig.
28,
lowering the presser foot.
• Loosen clamping screw
E,
Fig.
28.
• Raise
or
lower
guide
bracket
A,
as
required.
•
Make
certain presser
bar
is
positioned correctly
so
that
needle
will
locate centrally
between
the two
toes
of
the presser foot.
• Securely tighten screw
E.
Whenever guide bracket A, Fig.
28
has been
moved
on
presser bar, check the setting of check
spring as instructed on page 14.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
TO SET THE NEEDLE BAR AT THE
CORRECT HEIGHT
PREPARATION:
Remove face plate, slide plate and throat plate. See
that needle is correctly set in needle bar, as instructed
on page 5.
CHECK:
When shuttle point passes centre of needle, top of
needle eye should be approximately 1 /16 inch below
point
of shuttle. See Fig. 29.
ALTERNATE CHECK:
The gauge distance from throat plate seat to needle
·stop in needle. bar (at lowest point) should be 1.004
inches, as indicated in Fig. 30.
SETTING:
Loosen clamping screw F, Fig. 30. Raise or lower
needle
bar, as required. Then securely tighten screw F.
Replace throat plate, slide plate and face plate.
TO TIME THE SHUTTLE
EXPLANATION:
Timing of shuttle is fixed at the factory for normal
sewing conditions
at a 1 /10 inch loop lift.
This is accomplished by pinning the shuttle driver at
one end of the oscillating shaft and then pinning crank
G, Fig. 31 at the other end of the shaft at the specified
timing location.
TO CHECK THE TIMING:
Turn the machine pulley over toward you until needle
bar descends to lowest point and then rises approxi-
mately 1/ 10 inch.
At this setting, for normal sewing, the point of the
shuttle should
be at the centre of the needle as shown
in Fig. 29.
TO RE-SET THE TIMING:
When it becomes necessary to replace one or more
of the shuttle driving parts or to alter the timing to suit
a particular sewing condition, remove pin H, Fig. 31.
Loosen set screw J, Fig. 31.
Move point of shuttle to desired timing position and
securely tighten set screw J in crank G.
Plug pin hole in shaft and drill new hole to receive
pin
in desired location.
Insert pin H.
13
Fig. 29. Relationship of Shuttle Point to Needle Eye
-------------------------------------~------------ .--
THROAT e
PLATE
sa~\
F
---------T-.
I1.004"
I
l
Fig. 30. Setting Needle Bar Height
Fig. 31. Setting the Oscillating Shaft Crank
to Time of Shuttle

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
14
Fig.
32.
Setting Height of Check Spring
Fig.
33.
Adjusting Tension on Check Spring
HEIGHT SETTING
PREPARATION:
Thread the machine.
CHECK:
Turn
machine pulley
over
toward you slowly. When
take-up lever begins to rise, spring K, Fig.
32
"checks",
showing a slight dip
and
a return to its highest position.
Later,
as
take-up lever
approaches
top
of
stroke,
setting the stitch, this "check" spring K should
be
drawn
all the
way
down.
As
lever descends, check spring
K
returns to rest.
TO
SET
THE
CHECK SPRING
SETTING:
To
obtain the slight dip
in
check spring when take-up
begins to rise, loosen screw
L,
Fig.
32.
Turn
stud
M,
Fig.
32
(at
the same time turning entire tension as-
sembly) either over
toward
leftto
lower
the spring's
resting position and decrease
its
movement, or
over toward right to raise the spring's resting
position and increase
its
movement. Securely tighten
set screw
L.
VARIATIONS (FOR MACHINE
331K4):
Under certain conditions
of
tacking,
it
may
be
neces-
sary
to set the check spring higher than
it
is
otherwise
normally set.
TENSION SETTING
PREPARATION:
Thread the machine. Securely tighten
set
screw
L,
Fig.
33.
Make certain thumb nut
is
on stud
M,
Fig.
33.
CHECK:
Tension on check spring K, Fig.
33,
should
be
suffi-.
cient to ensure action
at
top
speed;
but
still
light
enough to permit itself to
be
drawn all the
way
down
before
any
thread
is
drawn through the tension discs,
as
take-up lever
approaches
height
of
stroke.
Check spring setting should
be
reviewed
each
time a
different fo9t
is
applied
to machine.
SETTING:
Using
a
large
screwdriver
in
slot
of
stud
M,
turn stud
either
over
toward left to decrease tension
or
over
toward right
in
increase it,
as
shown
in
Fig.
33.
VARIATIONS:
The tension on the check spring may require a
different setting, depending upon the
thread
and
material used. Heavier
thread
or
bulkier material re-
quires more tension to ensure correct
thread
control.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
TO TIME THE FEED
CHECK:
Test feed assembly linkage for freedom of move-
ment. Action
of feed dog must be regular and smooth
for maximum efficiency
When the feeding movement is correctly timed--
• The feed dog stops moving toward the rear
just as the take-up lever reaches the top of its stroke.
• The
feed dog drops below surface of throat
plate just as needle is about to enter material.
TIMING:
•
Set the machine for longest stitch as instructed on
page 10.
• Turn up the cover plate at the rear of the machine
arm.
• Loosen
set screw N in feed eccentric P, Fig. 34.
• Rotate feed eccentric P as required to obtain
desired timing.
• Securely tighten
set screw N.
• Close cover plate at rear of arm.
TO SET THE FEED DOG AT THE
CORRECT HEIGHT
Before checking height
of feed dog, set the machine
for longest stitch,
as instructed on page 10.
When the feed dog is at its highest position, ap-
proximately the full depth of the rear teeth of the
feed dog should project above the top surface of
throat plate, as shown in Fig. 35.
Variations of feed dog height may be necessary to
balance the height with the presser foot pressure.
To adjust the height of the feed dog, loosen screw
0, Fig. 35 and raise or lower the feed bar R, Fig. 35,
as required.
When the feed dog is set to the desired height,
securely tighten screw
0.
15
Fig. 34. Timing the Feed
FULL DEPTH
OF REAR TEETH
Fig. 35. Adjusting Height of Feed Dog

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
fig.
36. Centralizing Feed Dog
AT
HIGHEST
POINT
Fig.
37.
Shuttle Race
16
s
TO
CENTRALIZE
FEED
DOG IN THROAT
PLATE
SLOTS
CHECK:
Feed
dog
should not contact
edges
of
throat
plate
slots.
SIDEWISE
SETTING:
Feed
dog
should travel on a line midway between
sides
of
throat
plate
slots. ·
Feed
dog
can
be
moved toward left
or
right,
as
required,
after
loosening two nuts S
and
screw
U,
fig.
36,
on screw centres
T.
To
move
feed
dog
toward left, loosen screw centre
T
at
left end
of
shaft
V,
as
required,
and
tighten the
other screw centre
an
equal
amount.
Make certain
that
screw centres hold
feed
rock shaft
V snugly
in
place without binding.
Then
securely tighten
both nuts S
and
screw
U.
LENGTHWISE
SETTING:
Set
machine for longest stitch
as
instructed on
page
10.
Feed dog should
be
set so
that
its movement
is
equidistant from front
and
rear
edges
of
throat
plate
slots.
Loosen clamping screw
U
and
move
feed
bar
R
and
rock shaft V,
as
required.
Securely tighten screw
U.
TO
REMOVE
AND
REPLACE
THE
SHUTTLE
RACE
REMOVAL (With needle
at
highest position):
Remove the two screws
W,
fig.
37.
Remove the shuttle
race
X,
Fig.
37,
from machine.
Shuttle Y may now
be
slipped
in
or
out
of
shuttle
race
X without difficulty.
REPLACEMENT
(With needle
at
highest position):
Slip shuttle
Y
into shuttle
race
X,
Fig.
37.
Turn
shuttle
in
shuttle
race
so
that
shuttle
will
correctly
engage
shuttle driver
Z,
fig.
37.
Install shuttle
race
with shuttle
in
machine.
Fasten with two screws
W,
fig.
37.
Tighten two screws
W.

From the library of Superior Sewing Machine & Supply LLC - www.supsew.com
To
get
replacements
that
are
the same
as parts
in
new
machines
..
.
BUY
PARTS
AND
NEEDLES
MADE
BY
SINGER**
TO
BE
DOUBLY
SURE
...
of
new machine performance, make sure
that
all
replacement
parts
and
needles
are
precisely
identical
to
those
in
new
SING
ER
machines.
Look
for
the
trademark
SINGER
or
SIMANCO
0
on
every
package
or
container
8
on
the
needle
or
numbered
part
TO
ALL
WHOM
IT
MAY
CONCERN:
The
improper
placing
or
renewal
of
the
trademark
"SINGER"
or
any
other
of
the
trademarks
of
The
Singer
Company
(all
of
which
are
duly
Registered
Trademarks)
on
any
machine
that
has been
repaired,
rebuilt,
reconditioned,
or
altered
in
any
way
whatsoever
outside
a
SINGER
factory
or
an
authorised
SINGER
agency
is
forbidden.
Needles in containers marked
"For
Singer Machines"
are
NOT
made
by
SINGER.