Pfaff 238 User manual

PFAFF
238
238-0
I
R 9030
Instruction Book
and
Service Manual
From the library of: Superior Sewing Machine & Supply LLC

/hphee ^ 238
( PFAFF) 238-0
High-Speed Zigzag Sewing Machine
Organized with iink take-up
and transverse rotary hook
instruction Book
and
Service Manuai
G-MPFAFFAG-KAISERSLAUTERN BRANCH
From the library of: Superior Sewing Machine & Supply LLC

Foreword
This Instruction book contains much vaiuable Information about Pfaff 238 and 238-0
high-speed zigzag sewing machines. Though not intended as a full-scale textbook capable
of answering all questions related to sewing exhaustively, it offers sufficient information
on the construction, function and operation of the various mechanisms to enable every
interested operator to get to know her machine and attain maximum efficiency as quickly
as possible.
The instructions for mechanics contained in the second part of this book will no doubt
be much appreciated by all maintenance men servicing our sewing machines since even
the best sewing machine will work satisfactorily only if it is employed properly and
serviced by an expert. We have made every effort to render the presentation of these
instructions as simple as possiblle and have included numerous illustrations in order
to afford a better understanding. We welcome any suggestions and recommendations
which you may wish to make.
G. M. PFAFF AG
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From the library of: Superior Sewing Machine & Supply LLC

Instructions for Operators
1. Brief Description of the Pfaff 238
The Pfaff 238 high-speed zigzag sewing machine Is an Improved version of the Pfaff 138
which has been redesigned to match our modern high-speed straight stitchers In out
ward appearance and sewing performance.
Like the Pfaff 138, It Is organized with link take-up and transverse rotary sewing hook
which features aspecial balancing collar In order to
ensure vibratlonless running.
The Pfaff 238 Is supplied in Models A and B for a maximum stitch length of down to 7
stitches per Inch.
The permissible top speed of the machine depends on the model and the stitch width.
Model B machines are normally fitted for a stitch width of 11/64", or 4.5 mm, and a top
speed of 3,500 s.p.m.
If desired, Model B machines can be fitted with a special parts set for a stitch width of
about 'A", or 6.0 mm, and maximum speed of 3,200 s.p.m.
As a special variety, the Pfaff 238 can be supplied In Model A for a maximum stitch
width of 5/32" and a sustained speed of 3,800 s.p.m.
2. Setting Up the Machine
In most Instanoes, the Pfaff 238 Is supplied for Individual power drive. Sewing head and
power table are packed separately.
The machine Is driven by a Va-HP clutch motor. (Type of current and voltage optional to
suit local requirements.)
Power Is transmitted from the motor to the sewing machine by means of a V-belt 25/64",
or 10 mm, wide and conforming to German DIN 2215 standards.
When connected to a 50-cycle power supply, the motor runs at a speed of 2,800 r.p.m.,
and when connected to a 60-cycle power supply, at 3,400 r.p.m.
The motor pulley can be easily exchanged In order to vary the maximum sewing speed,
as may be required.
The relationship between pulley diameter and maximum sewing speed Is Indicated In the
table below:
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Balance
Whppj nip.
Motor Speed 2,800
r.p.m.
Motor Speed 3,400 r.p.m.
dm
mm
D
mm
dm
mm
Motor
D
mm
Pulley Dia.
Order
No.
Stitches
per
Minute
dm
mm
Motor Pulley Dia.
D Order
mm No.
Stitdies
per
Minute
71 76 63 68
16-437 010-55 2,500 ---
71 76 67 72 16-437 020-55 2,600 - - - -
71 76 71 76 16-437 030-55 2,800 -- -
-•
71 76 75 80 16-437 040-55 3,000 63
68 16-437 010-55
3,000
71 76
80 85 16-437 050-55 3,200
67 72 16-437 020-55 3,200
71
76 85 90 16-437 060-55 3,400
71
76
16-437 030-55
3,400
71 76
90 95 16-437 070-55 3,600 75 80
16-437 040-55
3.600
71 76 95
100
16-437 080-55
3,800
80 85 16-437 050-55 3,800
dfn ~ effective diameter 0 = outside diameter
63 mm
= 2.48", 72 mm = 2.83", 85 mm = 3,35",
67 mm = 2.64",
75 mm = 2.95", 90 mm = 3.54",
68 mm = 2.67",
76 mm = 3.00",
95 mm = 3.74",
71 mm = 2.79",
80 mm = 3.15", 100 mm = 3.94".
dm
- 0 Fig. 2
Unpack the sewing head cautiously to avoid damage to the machine. After removing the
lid from the box, unscrew the wood screws which hold the cushioned wooden blocks
that support the machine in the box. Cautiously lift the machine out of the box, wipe off
the dust and mount the machine on the table so that it rests on the rubber pads.
To facilitate the mounting of the V-belt, slip it on the machine pulley first. Then slightly
lift the motor and pull the belt onto the motor pulley.
For adjusting the V-belt tension, please refer to the instructions which are furnished with
the motor.
The machine is dispatched without oil in the reservoir and must not be run while in
this condition.
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3. The Lubrication System
An oil reservoir has been Incorporated in the top cover of the machine (Figs. 4 &5)
which holds enough oil to ensure adequate lubrication of the arm shaft parts.
After pulling out plug C
(Fig. 3), fill about 4 Vs fl. oz. of ordinary sewing machine oil
(Order No. 280-1-120122) or a technical white oil having a viscosity of 150 R/68°F or
175 S/es'F Into the reservoir.
The oil in the reservoir will last for a longer time, depending on how long the ma<^ine is
in operation each day. Oil should be replenished when the red tip of the oil level gauge
which can be seen through the oil sight glass emerges from the surface of the oil.
Fig. 4 shows the
open oil reservoir with oil wick, Fig. 5 the bottom of the reservoir with
the lower end of oil wick D which protrudes into hole A and supplies oil to the arm
shaft center bearing.
The oil seeps through a vent hole into the hollow arm shaft and is distributed inside the arm
shaft by a packing. Emerging from additional vent holes, oil is supplied to the various
arm shaft bearings and the feed eccentric. Dripping oil is collected by a large oil drip
pan and
accumulates in a detachable plastic oil bottle. (Fig. 6)
R 7715
Fig. 3
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From the library of: Superior Sewing Machine & Supply LLC

From the library of: Superior Sewing Machine & Supply LLC

The oil which has accumulated in this bottle may be returned to the oil reservoir without
prior cleaning. After the oil has circulated in the machine several times, it Is advisable
to filter it through a piece of linen before it is returned to the reservoir. This will not
Impair its lubricity in the least. Used oil, naturally, may be employed for other lubrication
purposes as well.
All other oiling points which are marked by arrows in Figs. 3, 4, 5, 7 and 8 have to be
oiled by hand.
Special care should be taken in applying oil to the large oiling felt which supplies oil
to the needle vibrating eccentric and can be reached through aperture F(Fig. 5). This
pad should be soaked with oil regularly.
Put one drop of oil into the hook raceway each day the machine is in operation. Fre
quently take off the needle plate and remove the lint which has accumulated on its
underside and on the feed dog. This is very Important because the lint contains small
particles of dressing which have an abrasive effect on the sewing hook and, in time,
will cause excessive wear.
R 7722
Fig. 8
10
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4. Test-Running the Machine
Before you test-run the machine, carefully remove the rust preventative.
After the machine has been lubricated as instructed above, test-run the unthread ma
chine with a piece of fabric under the presser foot.
Before you plug the machine In, make sure that the voltage indicated on the rating plate
of the motor is within the tension range marked on the electric meter.
Also, make sure the machine pulley rotates in the proper direction, i. e. toward you. If
it does not, simply exchange the two wires at the motor terminals.
R 7685
Fig. 9
11
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5. Removing the Bobbin Case
Raise the take-up lever to its highest position. Reach under the table with your left hand,
open the bobbin case latch and pull out the bobbin case by holding this latch with thumb
and forefinger, as shown in Fig. 9.
While you hold the bobbin case by its open latch, the bobbin cannot fall out (Fig. 10).
R 7432
Fig. 10
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6. Winding the Bobbin
The Pfaff 238 is equipped with a bobbin winder which is mounted on the power table
(Fig. 11).
This bobbin winder requires no lubrication since its spindle runs in a sintered-metal
bushing.
The bobbin winder is stopped quietly by means of an adjustable leather pad.
Mount the bobbin winder on the table so that its pulley will not contact the driving belt
when the winder is disengaged.
Place an empty bobbin on bobbin winder spindle 5. Lead the thread from the spool on
pin 1 through thread guide 2 and clockwise around and between tension discs 3. Wind
a few turns of thread on the bobbin in clockwise direction.
Start the bobbin winder by depressing engaging lever 6. The bobbin winder will stop
automatically when the bobbin is full. The amount of thread to be wound on the bobbin
is regulated by turning screw 7. Turn this screw clockwise for more thread, or counter
clockwise for less thread.
If the thread should pile up at one end of the bobbin, loosen screw 4 and adjust the
tension bracket, as appropriate.
R 6767
m
». IT
Fig. 11
^^7
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7. Threading the Bobbin Case
Insert a full bobbin into the bobbin case so that the thread draws on the top from the
left toward the right (Fig. 12).
Hoid the bobbin firmly in the bobbin case, puli the thread into slot 1 and draw it under
the tension spring and into delivery eye 2. Turn the bobbin case so that the end of its
iatch points toward the right and place it on the center stud in the bobbin case base.
Press against the bobbin case until you hear it snap into place.
Failure to observe this precaution may result in bobbin case or needle breakage.
R 4345
Fig. 12
14
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8. Threading the Needle
Threading the Pfaff 238 Is simple because the thread passes down on the front of
the machine in the operator's field of vision.
As iiiustrated in Fig. 13, lead the thread from the spool on the thread unwinder up and
through the thread guide at the top of the rod, then down to thread guide 1 on top
of the machine arm, through both its holes, and through all three holes in thread re
tainer 2, clockwise around and between tension discs 3, through the loop of thread
check spring 4, under slack thread regulator 5, up and from right to left through the
hole of take-up lever 6, down and through thread retainer 7, and from front to back
through needle eye 8.
R 7723
Fig. 13
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9. Drawing Up the Bobbin Thread
Hold the end of needle thread and turn the balance wheel toward you until the needle
moves down and up again. Lightly pull the needle thread to draw the bobbin thread up
through the needle hole (Fig. 14). Lay both threads back under the presser foot.
Always turn the balance wheel toward you until the take-up lever is at its highest
point before you begin and after you have completed a seam.
Failure to observe this rule may cause the thread to jam In the hook raceway or to slip
out of the needle eye. If the above rule is observed, there is no need to hold both
threads when you begin to sew.
10. Regulating the Thread Tension
The neat appearance of the finished seam and its durability greatly depend on the
correct regulation of tensions.
The tensions are correctly balanced if the needle and bobbin threads interlock in the
center of the material, as shown in Fig. 16.
Fig. 14
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The needle thread tension is increased by turning tension nutM clockwise, and decreas
ed, by turning it counter-clockwise (Fig. 13).
The bobbin thread tension is regulated by means of the small hook screwdriver. Turn
tension screw z in for more tension, or out, for less tension (Fig. 15).
The tensions should be regulated according to the material to be sewn. Check to see
that the stitches are tightly drawn in without puckering the material, in straight sewing,
the stitches should lie in a straight line, and in zigzag sewing, should form a perfect
zigzag pattern on the lop and bottom of the material without kinking.
Fig. 15
The grade of thread used plays an important part in obtaining a perfect seam on any
material. Sheer fabrics require a thin and soft thread, whereas stiff and resistant threads,
because of their low resilience, are unsuitable for almost any fabric.
You will have to have a little experience in order to be able to tell which tension needs
adjustment.
Fig. 16
Fig. 17
Fig. 18
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In Fig. 17 either the upper tension is too tignt, or the lower tension too weak.
In Fig. 18
either the upper tension is too weak, or the lower tension too tight.
You will
have to decide in every individual case, if either the upper or the lower tension
needs to be adjusted, particulary when the thread forms small knots or kinks on top or
bottom of the fabric.
Always lower the presser bar before you adjust the upper tension. When the presser bar
is raised, it will automatically release the tension.
11. Regulating the Stitch Length
The stitch length is regulated by turning thumb nut S on the feed regulator lever (Fig.
19).
This applies to both straight and zigzag sewing.
Turn this thumb nut right for shorter stitches, or left, for longer stitches.
The numerals on the left of the slot indicate the stitch length in millimeters.
The feed regulator lever is permanently held down in forward feeding position by spring
action.
When you push the feed regulator lever up beyond the zero mark, the machine will feed
in reverse. The lever will return to its forward feeding position automatically, when re
leased (Fig. 19). This feature is particularly useful for backtacking.
•mi
R 7720
Fig. 19
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12. Regulating the Stitch Width
The stitch width is regulated by turning knob G which is located in the middie of the
machine arm (Fig. 20). The numerals on the zigzag scale indicate the stitch width in
millimeters.
When pointer Z is set on zero, the machine sews straight.
When you turn knob G to the left, the stitch width increases gradually and the machine
makes the zigzag stitch.
With the zigzag knob at the extreme left of its scale, the machine will make stitches
about 3/16" or V4" (4.5 or 6.0 mm) wide, depending on the machine model.
There is a small lug on the underside of pointer Z which engages in a notch of slide S.
Screw B serves to lock this slide in position.
If you set the zigzag knob on 2 and tighten screw B, for instance, the stitch width is
fixed and will not be disturbed by the vibrations of the machine when sewing. In spite of
this, knob G can be jerked to zero when a few straight stitches have to be made in back-
tacking the end of a seam. By the same token, knob G can be jerked to the left for a
wider zigzag stitch. Returned to the middle of the zigzag scale, pointer Z will again en
gage in notch R of slide S so that the previous stitch width setting will be restored
automatically.
Switching from straight to zigzag stitching as well as changing the stitch length and the
stitch width can be done while sewing.
R 7719
Fig. 20
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13. Setting the Needle Position
Lever H can be set in notch I, II or III and serves to move the needle from the center
to the left or right of the needle plate slot.
With lever H In notch I, the needle is at the extreme left of the needle plate slot in
straight sewing, and swings to the right in zigzag stitching.
When lever H is set in notch II, the needle is centered in the needle plate slot in straight
sewing, and swings both ways in zigzag stitching.
With lever H in notch III, the needle is at the extreme right of the needle plate slot in
straight sewing, and swings to the left in zigzag stitching.
The needle position can be changed while sewing. When the machine is not in opera
tion, however, raise the needle out of the fabric before you change the needle position.
Failure to observe this precaution may cause bending or breaking of the needle.
14. Regulating the Pressure on the Material
Smooth feeding and uniform stitching greatly depend on the correct amount of presser
foot pressure. Staggering stitches and feed markings on the underside of the fabric are
a direct result of incorrect pressure regulation.
To increase the pressure for heavier fabrics, turn screw V in, and to ease the pressure
for lightweight materials, turn it out (Fig. 13).
When stitching delicate and sheer fabrics, feed a piece of tissue paper under the mate
rial to protect it from the feed points and prevent puckering. This paper can be readiiy
pulled away after sewing has been completed.
15. Selecting the Correct Needle
The Pfaff 238 is fitted with round-shank needles.
Model A machines use short System133 needles which will not tremble, regardless ofthe
sewing speed, and hence assure neat seams.
Model B machines are equipped with System 134 R needles which are about 5/32", or
4 mm, longer and are available in a number of different point styles to suit various
materials.
Pfaff 238-115 cording machines use System 130 B needles with a smaller shank dia
meter. Pin tucks are made with two System 130 Br and Bl needles which are placed be
tween the needle holder jaws with their flat sides facing, and are secured in position by
tightening the needie
gauge regulating screw. To make three System 134 RFr RFI needles
having a flat on the right and left side of the shank, respectively, and two System 134
Rfmc needles whose shank is flattened on both sides.
The number indicating the needle size is identical with the diameter of the needle shaft,
or blade, expressed in hundredths of millimeters. Thus, if the diameter of a needle is
0.8 mm, its size Is 80.
20
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