331K4
Form K6542
(365)
SINGER
SERVICE MANUAL
331K1 and 331K4
*A Trademark of THE SINGER COMPANY
THE SINGER COMPANY
© 1962 by The Singer Company
Copyright Under International Copyright Union
All Rights Reserved under Inter-American Copyright Union
Printed in Great Britain
CONTENTS
PAGE
DESCRIPTION...............................................................3
LUBRICATION AND CLEANING...................................4
INFORMATION FOR OPERATION
Bed Slide (Slide Plate)
Belt Guard......................................................................3
Bobbin and Bobbin Case
Bobbin Winder..................................................
Capacity of Machine...................................................3, 12
Centralizing Feed Dog
Common Causes of Stitching Troubles
Description of Oil..........................................................4
Dimensions of Machine..................................................3
Drawing Up Bobbin Thread............................................8
Feed Dog
Feed, Reverse......................................................... 3, 10
Feed Timing
Graduated Stitch Indicator
Knee Lifter..................................................................... 3
Length of Stitch
Light Fixture....................................................................3
Link Take-up ..............................................................3, 6
Lint, Removal of Excess.................................................4
Machine Dimensions.................................................... 3
Machine Pulley...........................................................3, 11
Needles
Needle Bar.........................................................3, 12, 13
Needle Setting............................................................... 5
Needle to Shuttle, Clearance.
Perfect Stitch..................................................................8
Preparation for Sewing...................................................8
Presser Bar
Presser Bar Guide Bracket
Presser Foot
Pressure of Presser Foot
Pulley........................................................................ 3, 11
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............................13, 16
3, 12, 15
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4-11
7-9
4, 7
16
15, 16
15
10
3, 10
12
12
9, 15
INDEX
8
5
5
PAGE
ADJUSTMENTS
PARTS LIST
Reverse Feed
Rotary Tension................................................................3, 9
Setting Up Machine....................................................... 3
Shuttle
.....................................................................
Shuttle to Needle Clearance
Specifications............................................................3,12
Speed.............................................................................3
Starting to Sew...........................................................8, 11
Spillage, to Avoid............................................................7
Stand..............................................................................3
Stitch Indicator..............................................................10
Stitch Length
Stitch Type
Stitching Troubles, Causes of
Stop Motion...................................................................11
Table...............................................................................3
Tacking.........................................................................10
Take-up Lever
Take-up Lever Guard
Tension, Check Spring
Tension, Threads.............................................................8, 9
Thread
............................................................................
Threading, Bobbin Case.................................................7
Threading, Upper (Needle).............................................6
Throat Plate................................................................3, 16
Treated Material, Speed when Sewing
Treadling Procedure
Turning a Corner
Twist of Thread............................................................. 5
Unwinder
Upper Threading.............................................................6
Winder (Bobbin)...............................................................4, 7
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12-16
3, 10
13, 14
13, 16
.8
17
10
3
5
3, 6
3
14
5
3
11
3, 6
DESCRIPTION MACHINE 331K4:
Machines 331K1 and 331K4 produce top quality,
single-needle, straight-line lock stitching in suits, shirts,
skirts and other clothing.
MACHINE 331K1:
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.
Similar to Machine 331K1, 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
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 guard 174112 available on order.
Knee lifter 139625 regularly supplied.
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.
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. 5) through
holes in throat plate.
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. 3. Oiling Points—Rear View
Fig. 4. Oiling beneath Machine Bed
Fig. 5. Oiling Points behind Face Plate and in Shuttle Race
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.
Fig. 6. How to Determine the Twist
MOVE TO
HIGHEST POINT
N
LOOSEN SCREW
INSERT NEEDLE UP
LONG
GROOVE It
AS FAR AS POSSIBLE
AND TIGHTEN SCREW
Orders for needles must specify the Quantity
required, the Size number, also the Catalog number.
For example:
‘nOO Size 16, Catalog #2055
(16x87) 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.
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 burr on needle point may cause picking
or fraying of the material.
• Incorrect setting of needle.
UPPER THREADING
NOTE: 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 beneath 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.
MOVE NEEDLE BAR
TO HIGHEST POINT
Fig. 8. Upper Threading
HOLD LATCH AND
\r PULL CASE FROM
A SHUTTLE
""/A.)
Fig. 9. Removing Bobbin Case and Bobbin from Machine
I —o. RELEASE
LATCH
4. BOBBIN
DROPS OUT
Fig. 10. Removing Bobbin from Bobbin Case
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