Singer 250 Series User manual

Service Manual
• Registered Trademark
FORM 723 (1172)
SINGER*
SINGER FACTORY - MONZA
Series Machine Class
The Singer Company
C) 1972 Si nger Monza
All rights reserved

Mod. 252
Mod. 257
Mod. 259
2
FORM 723 (1172)

Specification of the 252 - 257 and 259 Class Machines
252
257
Automatic Zig-Zag Machine
Manual Zig-Zag Machine
General Features
Flat bed machines with electric or treadle drive.
Lock slilch machines.
Maximum stitch length: 4 mm. (6 s.p.i.).
Maximum stitch widlh: Approx . 5 mm. (3/16 inch): (252-257).
Presser bar lifl up lo engagement: Approx . 7.5 mm. (295").
Speed : Minimum 900 Stitches per minute.
Needle. Catalog 2020 (15 x 1) . Needle threading from front to back.
Vertical axis rolaling hook which makes two revolutions per stitch .
Easy front • drop - in • bobbin .
Comparison of the Particular Features
Hidden bobbin winder
Front • drop-in • bobbin
Rotating hook
FORM 723 (1172)
259
Slraighl Slilch Machine
252
X
X
X
257
X
X
X
259
X
X
X
3

Description of Machines
252 257 259
1. Snap-
on . Snap-off Presser Foot
X X X
2. Needle Clamp
X X X
3. Thread Tension
Regulator X X X
4. Thread Take-up X X X
5. Presser
Bar Pressure Regulating
Dial
X X X
6.
Bobb in Winder Thread Gui de
X X X
7. Control Panel X X
8. Bi ght Lever X X
9. Needle Position
Lever X X
10. Pallern Se lec tor Lever X
11 .
Spool Pin X X X
12 . Bobb in Win der
Lever and Spi ndle
X X X
13. Hand Wheel X X X
14.
Stitch Length Regulating Dial X
15. Reversing Button X
16. Bed S lide
X X X
17 . Rotary
Hook
X X X
18. Bobb in Case X X X
19. Bobb in X X X
20 . Cushion
Spring
X X X
21 . Throat Plate X X X
22. Feed Dog X X X
23. Presser
Bar
Liller Lever
X X X
24. Stitch
indicator Plate X X
25. Sti tch
Length Regulator
Lever X X
4 FORM
723 (1172)

22

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Contents
Specification of the machine .
Description of the machine
Contents
Guide for using this manual .
Lubrication
D Arm top cover
D Face plate
IOI
Presser
loot
pressure regulator
D
Presser
bar
llll:JIII
Needle bar
DI
Needle bar
bearings
IOI
Needle
bar vibrating bracket
D
Needle thread take-up and needle bar connecting
D
Needle thread tension
m Stitch width regulator
III Needle position and cam follower mechanism
m Cam stack and shall .
m Handwheel • clamp slop motion
m Bobbin winder
m Horizontal arm shall
m Vertical arm shall
IIJI Stitch length regulator and feed fork
m Feed actuating rod
m Rotating hook
EI!J Hook drive bell
m Feed mechanism • feed lift shall · actuating shall
m Wiring diagram
FORM 723 (1172)
link .
PAGE
3
4 / 5
6 / 1
8
10 /
11
12 /
13
12 /
13
14 / 15
14 / 15
16 / 17
18 /
19
20 / 21
22 / 23
24 / 25
26 / 27
28 / 29
30 / 31
32 / 33
34 / 35
36 / 37
38 / 39
40 / 41
42 / 43
44 / 45
46 / 47
48 / 49
51
7

Guides for Us i ng Service Manual
To obtain the maximum benefit from this service manual, the follow ing information should be
studied carefully:
In order to keep this manual simple and easy to use, a si ngle description has been used for all
types of machines. however. where there are differences between the three types, this has been
noted in the margins.
The NUMBERS (0 ,D .D etc .) used in this manual refer to specific assembly groups as
indicated in the table of contents. A given number always refers to the same assembly gro~p . For
example , D always refers to arm top cover .
The LETTERS (A, B, D, etc .) used in this manual refer only to the parts indicated in the torres -
ponding picture of a given assembly group . For example, the letter A does not refer to the same
part in assembly group -as it does in assembly group D .
REFERENCES to the machine (left, right, front, rear, upward. etc.) are made with the machine
being in its normal upright position with the control panel lac ing the operator .
Procedures for disassembling individual machine systems have been descr ibed in detai l. In general,
reassembly is done in the reverse order . Exceptions to this rule are explained whenever necessary.
The adjustments in each group should be done in the order they have been descr ibed without
omitt ing any. Wherever it is necessary to check or set adjustments of other assembly groups ,
either belore or alter ad justment, this will be indicated.
Belore disassembling a machine to find the causes for faulty operations, the machine should be
thorough ly cleaned and lubr icated. In do ing so, make sure that no oil gets i nto the motor.
Before undertaking any work on electrical parts (motor, light) disconnect· plug from the electr i cal
outlet.
The handwheel must always be turned towards the front of the machine when it must be moved
while performing adjustments.
The sets of gears are to be adjusted for smooth run and smallest amount of play and blacklash.
Use only lubricants which are recommended by SINGER.
Never apply abrasives such as emery or lapping pastes to plastic gears.
8 FORM
723 (1,172)
·-----

Notes
FORM 723 (1172) 9

Lubrication
1. Disconnect the machine from electrical outlet.
2. Remove D .g , open the bed slide and remove throat plate.
3; Remove lint, dust and foreign particles found in the machine.
4. Apply oil to the points indicated.
5. Lay the machine on its back and oil the points indicated.
I. Remove excess oil.
Note: a) The arrows In the illustration only show the most important lubricating points. Therefore,
it may also become necessary to lubricate or oil any other moving parts in the machine.
10 FORM 723
(11721

11

■
•
u o ·
e------..,
A ;....:.----7•~\
-----
12

■
Arm Top Cover
Removal:
1) Loosen screws A and B.
2) Lill off cover C.
IIFace Plate
Removal:
1) Remove screw A.
2) Remove face plate B.
FORM 723 (1172)
13

■ Presser Foot Pressure
Removal:
Regulator
14
1) RemoveD andO .
2) lower presser foot.
3) Turn pressure regulating dial to " DARN "' setting.
4) Remove screw A.
5) Remove dial 8.
6) Remove screws C.
7) Remove pressure regulator assembly D.
Caution on reassembly:
a) Make certain that the presser bar pressure pin is lodged in the cavity of presser bar E.
b) Make certain that pressure extention pin F is seated against outside cam surface G on knob 8.
Adjustment of presser foot pressure:
Note: Before adjusting presser foot pressure make certain that the presser foot is correctly adjusted
in he ight as explained underD .
Check:
1) Turn hand wheel until t he feed dog is in its lowest position.
2) lower lever J.
3) Dial 8 should be set at "O" setting.
4) The pressure is correct when a piece of paper can be moved freely under the presser foot
but witt, only a slight resistance.
Setting:
1) loosen screw H.
2) Ra ise or lower the presser bar E to obtain the correct pressure, making certain that the pressure
pin F is correctly on the cam surface G.
3) Tighten scr ew H.
4 Presser Bar Assembly
------
Removal:
1) Remove D, D andllllJI .
2) Remove screw A and presser foot 8.
3) lower lever J and loosen screws C and D.
4) Pu ll bushing E downwards, being careful with the thread cutter wh ich is very sharp.
5) l i ft guide F out of the slot and turn it to the right.
6) Remove pressure pin G, guide F, presser bar H, buhing E and pressure spring.
Note: Should it be necessary to ramove lifter lever J or tension releasing lever K then proceed
as described above.
Caution on reassembly:
a) Make certain that the thread cutter on the bushing E faces to the rear of the machine.
b) When bushing E is assembled, the top surface of the bushing should be aligned with the inner
surface of the arm.
Adjustments • Presser foot height
Check:
1) l i ft lever J and turn hand wheel until feed dog is in Its lowest position.
2) The distance between the inferi or surface of presser foot 8 and top surface of throat plate
should be between 7.35 and 7.60 (.290-.300).
3) lower lever J and verify that presser foot is aligned with the slots in the throat plate as in
sketch l.
Setting:
1) lower lever J and loosen screw C, ra i se or lower presser bar H as required to obtain correct
height. Assure sideways alignment as indicated by l .
2) Fasten screw C.
Note: After adjusting, check for correct pressure according to Ill.II.
FORM 723 ( 1172)

II C
~A
B G
E D
C
H
F
C
5 / 7.60 mm
I
L
FORM 723 (1172)
15

G
16 FORM
723 (1172)

■ Needle Bar
Removal:
1) Remove D and llllfll.
2) Loosen needle thumb screw A.
3) Remove needle .
4) Remove needle stop screw 8 togelher with thread guide C.
5) Remove needle clamp body D downward.
6) Remove needle bar gib .
7) Loosen screw E.
8) Remove needle bar F upward out ol machine.
Adjustments of needle bar height:
Check:
1) Turn hand wheel until needle bar F is at its lowest point .
2) At this point. upper timing mark G should be aligned with lower end of needle bar ball bushing .
Setting:
1) Loosen screw E. raise or lower needle bar F as r equired .
2) Align needle clamp body D parallel to front · edge of throat plate .
3) Tighten screw E.
Not~: Setting of needle bar in relation to throat plate is done in D . m and m .
FORM 723 (1172)
17

■ Needle Bar Bearings
Removal of upper needle bar beari ng :
18
1) Remove H and lfll
2) Loosen screw A.
3) Push the ball bushing B upwa r ds and remove retai ni ng collar C. bear ing bushing O and ball
bushing B.
Nole: Lubricate parts B and C prior to re-assembly.
Removal of lower needle bar bearing:
1) Remove H and lfll
2) Remove needle clamp bOCly as descr i bed in D . It is not necessary to remove needle bar.
3) Loosen screw E.
4) Remove adjusting screw F.
5) Remove ball bushing G and bearing bushing H down w ard .
Nole: Lubr i cate p arts G and H pr ior to re-assembly.
Adjustments:
Upper Needle Bar Beari ng :
1) Loosen sc r ew A.
2) Turn hand wheel unt il needle bar is in its lowest pos i tio n.
3) Press the retaining co ll ar C do wnw ard so lhat needle bar oall bushing B moves lreely and
without play.
4) Ti ghten scr ew A.
lower Needle Bar Bearing:
1) Loosen screw E.
2) Turn hand wheel until needle bar is in it s lowest positi on.
3) Turn adjusting screw F as required unt il the needle bar ball bushing G moves freely and without
play.
4) Ti ghten screw E.
Caution:
Ti ghtenin g of scre w E may cause l ow er needle bar bear ing to bind . In such a case, the adjusting
screw F has to be readjusted.
FORM 723 (1 172 )

II
D
E--
G
F G H F
FORM 723 (1172)
19

■
J
D
20
FORM 723 ( 11 72)