Singer 221 User manual

Supplement to
Form 21325
Machine 221
(566)
SERVICE MANUAL
SINGER*
MACHINE 221

Lightweight portable lockstitch machine with
reversible drop feed and electric drive. The motor is mounted on machine bed. Wiring to
motor and light is concealed in machine arm and
bed. The machine is equipped with a foot controller.
(Note: Machine 221K4 is also equipped with R. F.
Suppressors and grounded wiring.)
Rotary hook on horizontal axis, makes two rev-
olutions per stitch.
Light and light shade attached to front of ma-
chine arm with control switch located on bed. (Ma-
chine 221K4 has light switch built into the light
socket.)
Machine 221K7 is equipped with belt linkage be-
tween arm and hook shafts. Other varieties are
equipped with an upright arm shaft and gears.
Machine base 10-7/64 inches long, 7-1/4 inches
wide. Space at right of needle, 5 inches.
Presser bar light: 5/16 inch. Feed dog height:
.040 inch above throat plate.
Manually controlled bobbin winder attached to
belt guard.
Needle, Cat. 2020 (15xl), threaded from right
to left.
STITCH LENGTH
REGULATOR
I.
BOBBIN-WINDING
THREAD GUIDE
{
221.1- SERIES 3
221K4· CAK7
MOTOR 221K5- CAJ6-8
221K7:CAK8-8

Before inspection to find causes of faulty opera-
tion, the machine should be thoroughly cleaned
and lubricated.
Remove face plate and throat plate. Open arm
top cover and remove bottom cover.
Remove Iint and other foreign matter that may
have acc umu lated around the sewi ng area and clean
all exposed mov ing parts with a broom type ny Ion
brush dipped in varso '
CAUTION: KEEP VARSOL AWAY FROM ALL
RUBBER PARTS
Note: Under extreme conditions (if grease and
dirt is hard and tacky) remove motor, light and
wiring, as instructed on page 25, and soak machine
in a tan k of varsol unti I so lids have become softened.
CAUTION: Before dipping Machine 221K7 in
varsol, it wi II be necessary to remove the Arm Shaft
Connection Belt, as instructed on page 24.
With the face plate removed and arm top cover
removed or turned aside, apply a small amount of oil
or lubricant to each of the points indicated in Figs.
3, 4 and 5. Close arm top cover and replace face
plate.

T urn machine on its side, remove bottom cover
and apply oil or lubricant to each of the points In-
LUBRICANT
(Gear-Dr iven
Machine Only)
Never use oi Ior ordinary gear grease to lubricate
motor. Entrance of oil into motor may cause failure
of electrical components. Use MOTOR LUBRICANT
sold by The Singer Company.
The two motor grease tubes, Fig. 7/ should be
refi lied every 6 to 12 months, depending on machine
usage.

When presser foot is raised to highest point, dis-
tance between bottom of presser foot and top surface
of throat plate should be 5/16 inch, as shown in Fig.
8. (Note: The needle clamp, when at its lowest point,
should not strike the raised presser foot.)
Presser foot should be in alignment with throat
plate slots and feed dog, as shown in Fig. 9. Inset,
Fig. 9, shows correct alignment of presser foot with
need Ie.
Loosen, guide bracket set screw shown in Fig. 8
and raise or lower presser bar as required to obtain
correct he ight.
AIign presser foot with throat plate slots and
needle as shown in Fig. 9.
1. Remove bottom cover.
2. Set stitch length regulator for 12 to 15 stitches
per inch.
3. Turn hand wheel toward operator unt iI feed dog
is in its highest position.

With feed dog at highest poi nt, approxi mate Iy the
full depth of rear teeth should project above top
surface of throat plate.
Loosen hinge nut on FEED LIFTING ROCK
SHAFT, Fig. 12, and turn eccentric hinge screw
unti I high poi nt of eccentr ic is toward rotary hook
shaft. Then turn eccentric hinge screw as required to
correct he ight.
TO POSITION FEED DOG
IN THROAT PLATE SLOTS
Loosen hinge nut on FEED ROCK SHAFT, Fig.
12, and turn eccentric hinge screw until high point
of eccentric is away from rotary hook shaft. Then
turn eccentric screw as required to bring feed dog
in correct position.
Feed dog should move as close as possible to
front of throat plate slots without striking throat
plate.
FEED' LIFTING
ROCK SHAFT
ECCENTRIC HINGE
SCREW

CENTER
SET SCREW
FEED LIFTING
ROCK SHAFT
CENTER
SET SCREW
Feed dog should be centrally located between
the sides of the feed slots of the throat plate.
Loosen the four center set screws, Fig. 13, hold-
ing the feed rock shaft and feed lifting rock shaft
centers In place. To move feed dog toward the left,
gently tap the right hand center of the feed rock
shaft and feed I ifting rock shaft to the left unti I feed
dog is correctly positioned. Then tighten the four
set screws. To move feed dog toward the right, gently
tap the left hand centers to the right unti Ifeed do,g
is correctly positioned.
NOT E: Check for end play or binding in feed rock
shaft and feed lifting rock shaft. To adjust, loosen
center set screw at right end of mach ine and move
center as requi red.

T urn hand wheel over toward operator unti I needle
bar is at its lowest point. At this position, upper
timing mark, Fig. 14, should be just visible at lower
edge of needle bar bushing.
Loosen clamp screw/ Fig. 14, and raise or lower
needle bar as required. Make certain needle bar is
correctly turned with long groove in needle facing
toward right of mac.h ine. Then tighten clamp screw.
If there is any belief that the needle bar bushing
has been disturbed, it will be impossible to set the
needle bar by use of the timing marks.
Remove bobbin case and bobbin. With needle
threaded, hold thread end and turn hand wheel. over
toward operator unti I needle reaches its lowest point
and rises approximately 1110 inch. At this point the
needle thread loop should be fully formed, Fig. 15,
and ready for entrance of hook po int di rectly above
needle eye.
Loosen clamp screw, Fig. 14, and raise or lower
needle bar as required. Make certain long groove of
needle is facing toward right of machine an'd tighten
clamp screw. Then set the needle bar bushing.
With needle bar set at correct height, turn hand
wheel over toward operai or unti I need Ie bar is at its
lowest point. In this position the upper timing mark
on the needle bar should be at bottom edge of the
bushing.
Loosen needle bar bushing set screw, Fig. 14,
and raise or lower bushing as required. Then tighten
set screw.
BUSHING
SET SCREW
HOOK
POINT
NEEDLE
EYE

Remove throat plate and turn hand wheel over
toward operator unti I lower timing mark on needle
bar is at lower edge of needle bar bushing on its
upward stroke. With needle bar in this position, the
di stance between the side of needle and point of
hook, as shown in insert in Fig. 16, should be .005".
This is approximately the thickness of a piece of
ordinary note paper.
Loosen counterbalance set screw, Fig. 16, and
move counterbalance away from bushing. Loosen one
hook set screw. Turn bal ance wheel toward operator
to position needle bar as instructed above. Loosen
the other hook set screw and bushing set screw.
Using a 114" brass drift pin, gently tap bushing jo
left or right as required. Press hook assembly against
bushing and tighten hook and bush ing set screws. Re-
check setting and replace counterbalance with hub
against bushing.
LOWER
TIMING
MARK
HOOK POINT
ENTERING
THREAD LOOP UPWARD STROKE
NEEDLE EYE
1/16 INCH BE LOW
HOOK POINT
Set needle bar height and position of hook to or
from needle as previously instructed.
With needle threaded, turn hand wheel over toward
operator unti I needle bar reaches lowest point and
rises to position where lower timing mark on needle
bar, Fig. 17, is just visible at lower edge of needle
bar bushing. With needle bar in this position, the
point of the hook should be approximately 1116"
above the needle eye and entering the needle thread
loop.
Remove bottom cover. Loosen rotating hook shaft
pulley set screws, Fig. 18, or hook shaft bevel gear
set screws in gear driven machines. Turn shaft man-
ually until point of hook is in its correct position
to the needle eye and needle thread loop, as shown
in Fig. 17. While holding hook in this position, tighten

CAUTION: In gear driven machines, do not disturb
mesh of bevel gears.
The take-up spring, Fig. 19, should complete its
action and be at rest against take-up spring stop as
point of needle enters material.
To adjust the take-up spring stroke, loosen set
screw, Fig. 19. Move slack thread regulator to the
right to complete take-up spring action earlier
(shorter stroke) or to the left to complete take-up
spr ing acti on Iater (Ionger stroke). Then securely
tighten set screw.
Tension on the take-up spring should be just
sufficient to take up the slack of needle thread until
point of needle enters material.
Turn tension dial to zero, remove face plate and
loosen stud set screw, Fig. 20. Remove entire ten-
tion assembly from machine. Slide end of take-up
spring, Fig. 20, out from groove in tension stud.
Turn end of spring toward right (CLOCKWISE) to in-
crease ten sion or toward left (COUNTERCLOCKWI SE)
to decrease tension and place it in nearest groove.
Replace tension assembly, drawing take-up spring
up so it rests on take-up spring stop, Fig. 19, and
securely tighten set screw.
TAKE·UP
SPRING
TAKE-UP
SPRING
STOP

ADJUSTING
SCREW
With machine threaded, lower presser bar to en-
gage tension and turn tension regulator dial to zero
(0) position, Fig. 21. Hold thread on both sides of
tension regulator and pull back and forth through
tension discs. The tension on the thread should be
just slightly perceptible, which gradually increases
with the turning of the regulator dial to the right.
If the pull on the thread is too strong for minimum
tension, press in numbered dial to disengage pin in
thumb nut, Fig. 21, from dial. Reset pin in next
hole to the left of previou s setting. Repeat process
unti I there is no tension on thread. Then advance
pin one hole to the right to produce minimum tension
at zero (0) position.
Remove threaded bobbin case and bobbin from
machine. Hold end of bobbin thread allowing the bob-
bin case and bobbin to hang free. When tension is
correctly adj usted, the bobbin case wi II descend
slowly each time the thread is given a slight "jerk"
upward. When using a tensiometer, a bobbin thread
tension of approximately 50 grams is sufficient for
No. 50-3 mercerized cotton.
Gradually turn tension regulating screw for either
increased or decreased tens ion, as shown in Fig. 22.
The pressure of the bobbin winder pulley against
the belt should be just enough to operate the bobbin,
winder without slippage.
Ti ghten adj u sting screw, Fig. 23, suffi c iently to
increase pressure of pulley again st belt.

TO ELIMINATE END PLAY OR BINDING
OF HORIZONTAL ARM SHAFT
Shou Id the hori zontal arm shaft require adjustment
for end play or binding, remove hand wheel as in-
structed on page 23 to expose hand wheel bu shing.
Loosen set screws, Fig. 24, and move hand wheel
bushing slightly away from arm shaft bushing. Insert
a .003 feeler gauge between the two bushings, move
hand wheel bushing back against the feeler gauge,
and tighten setscrew. Replace hand wheel.
TO ELIMINATE END PLAY OR BINDING
OF UPRIGHT ARM SHAFT
(GEAR DRIVEN MODELS)
Open top cover and remove bottom cover. Loosen
set screws, Fig. 25, in lower verti cal bevel gear.
Press downward upon upright arm shaft. Set lower
vertical bevel gear firmly against lower bushing In
casting and securely tighten gear set screw.
Check mesh of upper and lower vertical and hor-
izontal bevel gears to ascertain that they are fully
meshed. To adjust, loosen horizontal bevel gear set
screws, Fig. 25, and slide gear to position where it
is correctly meshed with vertical gear. Then tighten
set screws and replace covers.
CAUTION: Bevel gears must always be kept In
mesh at all times.

TO ELIMINATE END PLAY OR BINDING
OF HOOK DRIVING SHAFT
Binding may be caused by lack of lubrication
or foreign material obstructing moving parts. Clean
and lubricate as instructed on page 5.
To eliminate end play or binding in hook driving
sh aft} loosen counterbal ance set screw and bu sh ing
set screw, Fig. 26. Position shaft as required to
eliminate binding or end play and move bushing
against the hook, taking care to maintain correct
SET
SCREW
FEED LIFTING
ROCK SHAFT
clearance between needle and hook, see page 10.
Place counterbalance against bushing and tighten
set screws. In gear-driven machines, it may be neces-
sary to loosen set screws in hori zontal hook shaft
bevel gear while making this adjustment. Then tight-
en set screws.
Recheck clearance between needle and hook and
check the hook timing. See page 10.
SET
SCREW
HOOK
SHAFT
TO ELIMINATE END PLAY OR BINDING
OF FEED ROCK SHAFT AND FEED LIFTING ROCK SHAFT
To eliminate end play or binding of feed rock
shaft, loosen set screw at right end of shaft, Fig.
26, and adjust center shown so that shaft rides
snugly but freely, {without left or right movement}.
rock shaft, loosen set screw at right end of shtlft,
Fig. 26, and adjust center shown as required.
Check position of feed dog and adjust as re-
quired. See page 6.

1. Remove face plate.
2. Loosen set screw In needle clamp as shown in
Fig. 27 and remove clamp.
3. Loosen clamping screw, Fig. 27, and lift needle
bar up through bushing and out of machine.
1. Insert needle bar down through bushing shown in
Fig. 27.
2. Replace needle clamp and tighten set screw.
3. Adjust needle bar height as instructed on page 9.
4. Make certain the needle bar is turned correctly,
then tighten clamping screw.
5. Replace face plate.
1. Remove face plate.
2. Remove presser foot and thumb screw.
3. Remove pressure regulating thumb screw, exten-
sion pin and spring, as shown in Fig. 28.
4. Remove thread cutter (earlier machines only).
5. Loosen guide bracket set screw, Fig. 28, and lift
presser bar up and out.
1. Replace presser bar through guide bracket, Fig.
28, and bushing.
2. Replace extension pin, spring and regulating
thumb screw.
3. Replace foof and thumb screw.
4. Set presser bar at correct height, see page 6,
and align foot with throat plate slots.
5. Tighten guide bracket set screw.
6. Replace face plate.
NEEDLE
CLAMP

HINGE SCREW
AND WASHER NEEDLE BAR
BUSHING SET SCREW
1. Remove face plate.
2. Remove presser bar and needle bar as instructed
on page 15.
3. Loosen set screw, Fig .. 29, an.d remove needle
bar bu sh ing.
4. Remove hinge screw and washer.
5. Turn hand wheel until thread take-up set screw,
Fig. 29, is accessible through access hole In rear
of mach ine.
6. Loosen thread take-up set screw and remove take-
up linkage.
CAUTION: Take-up lever cap screw has a left
hand thread. For removal, it must be turned
CLOCKWISE
1. Replacetake-up linkage in reverse order instructed
for removal with flat of stud toward thread take-
up set screw, Fig. 29.
2. Replace washer, take-up link and hinge screw.
3. Replace needle bar bushing.
4. Replace needle bar and presser bar as instructed
on page 15.
5. Set presser bar height, as instructed on page 6,
and needle bar height (without timing marks) as
instructed on page 9.
6. Set ne,.edle bar bushing as instructed on page 9,
and replace face plate.
1. Turn thumbnut to left until zero (0) on dial reaches
indicator line.
2. Loosen stud set screw, Fig. 30, and remove en-
tire assembly from machine.
3. Press in on dial, Fig. 31, dise"lgage pin in thumb
nut from hole in dial.
4. Hold dial in and remove thumb nuL
5. Remove dial, stop washer, tension spring, In-
di cator and tension di sc assembly which includes
thread guard, two discs and take-up spring.

TAKE-UP
SPRING
1. Make certain that releasing pin is In place as
shown in Fig. 3l.
2. Place tension discs, with convex sides together,
on thread guard as shown in Fig. 32.
3. Pass eyelet of take-up spring under thread guard,
keeping coils of spring above tension discs as
shown in Fig. 32.
4. Align coils of spring with hole in discs and place
this assembly on stud as shown in Fig. 33. Tail
of thread guard enters hole provided in machine
head.
Note: Tail of spring, Fig. 33, enters one of the
grooves in rear of stud. (See instructions for
setting take-up spring, page 11.)
5. Replace indicator, open side out, on stud with
plus and minus indications at top as shown in
Fig. 3l.
6. Insert tension spring into indicator and replace
stop washer as shown in Fig. 3l.
7. Place numbered dial on stud with numeral 2 op-
posite stop washer extension. Press in dial to
compress spring. While holding in, replace thumb
nut, carefully guiding pin into one of the holes
in the dial.
8. Replace entire tension assembly into machine and
tighten set screw.
9. Adjust tension as instructed on pages 11 and 12.
THREAD
GUARD

1. Remove throat plate and bobbin case.
2. Remove gib screw, Fig. 34, 'and displace gib as
shown in Fig. 35.
3. Turn bobbin case base so small point on bobbin
case base is beneath point of sewing hook as
shown in Fig. 35.
4. Remove base by lifting upward and out.
1. Replace bobbin case base in position as shown
in Fig. 35. Rotate it slightly until it seats.
2. Return gib to original position and replace screw.
3. Replace throat plate, making certain that the posi·
tion finger is in notch of position plate under
throat pIate.
BAS\E GIB
SP~ ,o~,~~E'
RETAINING____..
ll ~
SCREW IJ GIB
Fig, 36, Sewing Hook Disassembled
SCREWS
Fi'g, 37. Rear View of Sewing Hook
GIB
SCREW
1. Remove throat piate, bobbin case and bottom
cover.
2. Loosen two set screws in hub of hook, .Fig. 37,
and remove hook from hook shaft.
3. Remove retaining screw and spring, Fig. 37,
from rear of hook.
4. Remove gib screw a~d gib, Fig. 38, from front of
hook.
5. Li ft bobbin case base from face of hook.
1. Place base in its seat in.hook.
2. Replace gib and gib screw on front of hook as
shown in Fig. 38.
3. Replace spring and retaining screw on rear of
hook as shown in Fig. 37.
4. Replace hook on hook shaft, position in relation
to needle and reset time as instructed on page 10.
5. Replace bottom cover and throat plate.

1. Remove needle, throat plate and bobbin case.
2. Turn machine over on rear side and remove bottom
cover.
3. Loosen two set scr'ews, Fig. 39, in hub of hook
assembly.
4. Remove assembly from hook shaft.
1. Replace assembly on hook shaft.
2. Replace needle.
3. Adjust clearance between hook and needle, and
reset timing. (See page 10 for instructions.)
4. Repl ace bottom cover, bobbin case and throat
plate.
OLD
SHAFT
THREE-PIN
TERMINAL
HOOK SHAFT
BEVEL GEAR
1. Remove needle, throat plate, bobbin case and
bottom cover.
2. Remove rotating hook assembly, as previously
instructed, and bobbin case base as instructed on
page 18.
3. Loosen counterbalance set screw and hook shaft
bevel gear set screws. (See Fig. 40.)
CAUTION: MARK RELATIVE POSITION OF
MATED BEVEL GEARS to insure proper mesh
on later assembly.
4. Remove screw holding the three-pin terminal,
Fig. 40, and carefully push aside the wiring to
expose right end of hook sh aft.
5. Using new shaft as a tool, push old shaft out
through left end of machine. Make certain that the
inserted end of the new shaft presents the flats,
Fig. 40, on wh ich the rotary hook set screw and
counterbalance set screw, respectively, are to be
tightened.
1. Replace rotating hook on hook shaft being certain
that left end of shaft is flush with face of hook,
when hub of hook is against shaft bushing. The
set screw in hub, nearest the hook point, should
engage flat of shaft. Tighten set screws in hub.
2. Check position marking on hook shaft bevel gear
and tighten set screws while gear is against
bushing at right end of shaft.
3. Hold counterbalance against bushing and tighten
set screw against flat of shaft.
4. Reassemble the bobbin case base in the hook.
(In machines using the old style hook, it wi II be
necessary to remove the hook from the shaft. See
instructions on page 18.)
5. Check for binding and end play, as instructed on
page 14.
6: Replac~ needle and adjust clearance between
hook and needle and reset hook timing, as in-
structed on page 10.
7. Replace three-pin terminal, bottom cover, bobbin
case and throat plate.

Proceed as instructed for gear-driven machines
except as follows:
1. Do not di sturb wi ring.
2. Loosen set screws in hook shaft pulley, Fig. 41,
counterbalance and hook assembly. Remove old
shaft out through left end of machine. Do not use
new shaft as a tool.
Proceed as instructed for gear-driven machines
except as follows:
1. Insert new shaft from the left.
2. Insert shaft through pulley and belt. Place pulley
against right end bushing and tighten set screws.
1. Remove hand wheel as instructed on page 23.
2. Remove stitch indi cator plate screws, Fig. 42,
regulator hinge screw and spring washer.
3. Remove feed regulator and indicator plate as a
unit.
1. Insert regulator into the machine. Make certain
that the roller of feed forked connection rides in
slideway of regulator block.
2. Replace hinge screw and washer. The prongs of
the washer should face inward.
3. Repl ace indicator plate screws.
4. Replace hand wheel as instructed on page 23: