Pfaff 1425 User manual

Instruction Manual
296-12-18 092
Betriebsanleitung engl. 10.98
1425
1426

This instruction manual applies to all versions and subclasses listed under
"Specifications".
Reprinting, copying or translation of PFAFF instruction manuals, whether in whole or in part,
is not permitted without our prior permission and not without written indication of the
source.
G.M. PFAFF
Aktiengesellschaft
Postfach 3020
D-67653 Kaiserslautern
Königstr. 154
D-67655 Kaiserslautern
Editing/illustrations
HAAS-Publikationen GmbH
D-53840 Troisdorf

Contents
Contents ...............................................................................Chapter - Page
1Safety ........................................................................................................................ 1 -1
1.01 Regulations................................................................................................................ 1 -1
1.02 General notes on safety ............................................................................................ 1 - 1
1.03 Safety symbols ......................................................................................................... 1 - 2
1.04 Important notes for the user..................................................................................... 1 - 2
1.05 Notes for operating and technical staff .................................................................... 1 - 3
1.05.01 Operating staff .......................................................................................................... 1- 3
1.05.02 Technical staff...........................................................................................................1- 3
1.06 Danger warnings ....................................................................................................... 1 - 4
2Proper use ................................................................................................................ 2 - 1
3Specifications .......................................................................................................... 3 - 1
3.01 PFAFF 1425, PFAFF 1426 .......................................................................................... 3 - 1
3.02 Possible work aids .................................................................................................... 3 - 2
4Machine disposal..................................................................................................... 4 - 1
5Transportation, packing and storage..................................................................... 5 - 1
5.01 Transportation to customer's premises ................................................................... 5 - 1
5.02 Transportation inside customer's premises ............................................................. 5 - 1
5.03 Disposal of packing materials................................................................................... 5 - 1
5.04 Storage ......................................................................................................................5- 1
6Explanation of symbols........................................................................................... 6 - 1
7Controls .................................................................................................................... 7 - 1
7.01 On/off switch ............................................................................................................ 7 - 1
7.02 Keys on machine head .............................................................................................. 7 - 1
7.03 Pedal .......................................................................................................................... 7 - 2
7.04 Knee switch............................................................................................................... 7 - 2
7.05 Presser foot fixing key .............................................................................................. 7 - 3
7.06 Stich-length setting ................................................................................................... 7 - 3
7.07 Reverse-feed control ................................................................................................. 7 - 4
7.08 Edge trimmer -731/02................................................................................................ 7 - 4
7.09 Secondary needle-thread tension .............................................................................. 7 - 5
7.10 Setting quick-change stepping control -918/29 ......................................................... 7 - 5
7.11 Bobbin-thread supply monitor -926/06 ...................................................................... 7 - 6
8Installation and commissioning............................................................................. 8 - 1
8.01 Installation................................................................................................................. 8 - 1
8.01.01 Adjusting the table height.......................................................................................... 8 - 1
8.01.02 Fitting the tilt lock .....................................................................................................8- 2
8.01.03 Tensioning the v-belt ................................................................................................. 8 - 2
8.01.04 Fitting the top v-belt guard ........................................................................................ 8 - 3
8.01.05 Fitting the bottom v-belt guard.................................................................................. 8 - 3
8.01.06 Fitting the synchroniser............................................................................................. 8 - 4
8.01.07 Fitting the reel stand ................................................................................................. 8 - 4

Contents
Contents ...............................................................................Chapter - Page
8.02 Commissioning.......................................................................................................... 8 - 5
8.03 Switching the machine on/off ................................................................................... 8 - 5
9Setting up ................................................................................................................. 9 - 1
9.01 Inserting the needle on the PFAFF 1425 ................................................................... 9 - 1
9.02 Inserting the needles on the PFAFF 1426.................................................................. 9 - 2
9.03 Winding the bobbin thread, regulating the winder tension ....................................... 9 - 3
9.04 Bobbin-changing/threading, and regulating the bobbin thread tension ..................... 9 - 4
9.05 Threading needle thread and regulating its tension on the PFAFF 1425 ................... 9 - 5
9.06 Threading needle threads and regulating tensions on the PFAFF 1426 ................... 9 - 6
9.07 Setting the stitch length ............................................................................................ 9 - 7
9.08 Setting the feed stroke.............................................................................................. 9 - 7
10 Care and maintenance........................................................................................... 10 - 1
10.01 Cleaning the hook area............................................................................................ 10 - 1
10.02 Oiling the hook ........................................................................................................ 10 - 2
10.03 Checking/adjusting the air pressure........................................................................ 10 - 3
10.04 Cleaning the air filter of the air-filter/lubricator....................................................... 10 - 3
11 Adjustment............................................................................................................. 11 - 1
11.01 Tools, gauges and other equipment ........................................................................ 11 - 1
11.02 Notes on adjustment............................................................................................... 11 - 1
11.03 Abbreviations........................................................................................................... 11 - 1
11.04 Adjusting the basic machine ................................................................................ 11 - 2
11.04.01 Adjusting the synchronizer...................................................................................... 11 - 2
11.04.02 Balance weight........................................................................................................ 11 - 3
11.04.03 Neutral position of the unison feed ......................................................................... 11 - 4
11.04.04 Feeding motion of the unison feed.......................................................................... 11 - 5
11.04.05 Lifting motion of the bottom feed dog .................................................................... 11 - 6
11.04.06 Height of the bottom feed dog ................................................................................ 11 - 8
11.04.07 Needle in needle-hole centre ................................................................................... 11 - 9
11.04.08 Feeding-stroke difference........................................................................................ 11 - 10
11.04.09 Needle height (preliminary adjustment) .................................................................. 11 - 11
11.04.10 Needle rise, hook clearance, needle height (final adjustment) and needle guard .. 11 - 12
11.04.11 Bobbin-case opener stroke...................................................................................... 11 - 14
11.04.12 Top feed stroke ....................................................................................................... 11 - 15
11.04.13 Top feed lifting motion ............................................................................................ 11 - 17
11.04.14 Clearance between lifting presser and needle plate............................................... 11 - 18
11.04.15 Bobbin winder.......................................................................................................... 11 -19
11.04.16 Thread check spring and thread regulator on the PFAFF 1425 ............................... 11 - 20
11.04.17 Thread check springs and thread regulator on the PFAFF 1426 ............................. 11 - 21
11.04.18 Maximum sewing speeds ....................................................................................... 11 - 22
11.04.19 Speed reduction on increase of stitch length.......................................................... 11 - 23
11.04.20 Speed reduction on increase of stroke ................................................................... 11 - 24

Contents
Contents ...............................................................................Chapter - Page
11.04.21 Needle-thread tension release ................................................................................ 11 - 25
11.04.22 Lubrication ............................................................................................................... 11 - 26
11.04.23 Re-engaging the slip-clutch ..................................................................................... 11 - 27
11.04.24 Parameter adjustments........................................................................................... 11 - 28
11.05 Adjusting the edge trimmer -731/02 .................................................................... 11 - 29
11.05.01 Neutral position of knife .......................................................................................... 11 - 29
11.05.02 Knife stroke ............................................................................................................. 11 - 30
11.05.03 Cutting stroke.......................................................................................................... 11-31
11.05.04 Actuating lever ........................................................................................................ 11 -32
11.05.05 Knife height..............................................................................................................11-33
11.05.06 Knife position in sewing direction ........................................................................... 11 - 34
11.05.07 Knife position crosswise to sewing direction ......................................................... 11 - 35
11.06 Adjusting the thread trimmer -900/81 ................................................................ 11 - 36
11.06.01 Resting position of roller lever / radial position of control cam .............................. 11 - 36
11.06.02 Thread catcher height.............................................................................................. 11 - 37
11.06.03 Thread catcher position........................................................................................... 11 - 38
11.06.04 Knife height..............................................................................................................11-39
11.06.05 Knife pressure ......................................................................................................... 11 -40
11.06.06 Bobbin-thread retaining spring ................................................................................ 11 - 41
11.06.07 Thread-catcher transmission crank (only on PFAFF 1426 ) .................................... 11 - 42
11.06.08 Transmission linkage (only on PFAFF 1426 )........................................................... 11 - 43
11.06.09 Manual cutting test ................................................................................................. 11 - 44
11.07 Adjusting the bobbin-thread supply monitor -926/06 ........................................ 11 - 45

1 - 1
Safety
1 Safety
1.01 Regulations
This machine is constructed in accordance with the European regulations indicated in the
conformity and manufacturer's declarations.
In addition to this instruction manual, please also observe all generally accepted, statutory
and other legal requirements, including those of the user's country, and the applicable pol-
lution control regulations!
The valid regulations of the regional social insurance society for occupational accidents or
other supervisory authorities are to be strictly adhered to!
1.02 General notes on safety
●The machine must only be operated by adequately trained operators and only when the
instruction manual has been fully read and understood!
●All notices on safety and the instruction manual of the motor manufacturer are to be
read before the machine is put into operation!
●All notes on the machine concerning danger and safety must be observed!
●The machine must be used for the purpose for which it is intended and must not be
operated without its safety devices; all regulations relevant to safety must be adhered
to.
●When part sets are changed (e.g. needle, presser foot, needle plate, feed dog or bob-
bin), during threading, when the workplace is left unattended and during maintenance
work, the machine must be isolated from the power supply by turning off the on/off
switch or removing the plug from the mains!
●Daily maintenance work must only be carried out by appropriately trained persons!
●Repairs and special maintenance work must only be carried out by qualified technical
staff or persons with appropriate training!
●During maintenance or repairs on the pneumatic system the machine must be isolated
from the compressed air supply! The only exception to this is when adjustments or
function checks are carried out by appropriately trained technical staff!
●Work on the electrical equipment must only be carried out by technical staff who are
qualified to do so!
●Work on parts or equipment connected to the power supply is not permitted! The only
exceptions to this are specified in regulations EN 50110.
●Conversion or modification of the machine must only be carried out under observation of
all relevant safety regulations!

1 - 2
Safety
●Only spare parts which have been approved by us are to be used for repairs! We draw
special attention to the fact that spare parts and accessories not supplied by us have not
been subjected to testing nor approval by us. Fitting and/or use of any such parts may
cause negative changes to the design characteristics of the machine. We shall not ac-
cept any liability for damage caused by the use of non-original parts.
1.03 Safety symbols
Danger!
Special points to observe.
Danger of injury to operating or technical staff!
1.04 Important notes for the user
●This instruction manual belongs to the equipment of the machine and must be available
to the operating staff at all times.
This instruction manual must be read before the machine is operated for the first time.
●Both operating and technical staff must be instructed on the safety devices of the mach-
ine and on safe working methods.
●It is the duty of the user to operate the machine in perfect running order only.
●The user must ensure that none of the safety devices are removed nor put out of work-
ing order.
●The user must ensure that only authorized persons operate and work on the machine.
For further information please refer to your PFAFF agency.

1 - 3
Safety
1.05 Notes for operating and technical staff
1.05.01 Operating staff
Operating staff are the persons responsible for setting up, operating and cleaning the mach-
ine and for removing any disturbances in the sewing area.
The operating staff are obliged to observe the following points, and must:
●always observe the notes on safety in this instruction manual!
●avoid using any working methods which adversely effect the safety of the machine!
●avoid wearing loose-fitting clothing or jewelry such as necklaces or rings!
●also ensure that only authorized persons are allowed near the danger area of the
machine!
●immediately report to the user any changes to the machine that may affect its safety!
1.05.02 Technical staff
Technical staff are persons who have been trained in electrical engineering, electronics,
pneumatics and mechanical engineering. They are responsible for lubricating, servicing,
repairing and adjusting the machine.
The technical staff are obliged to observe the following points, and must:
●always observe the notes on safety in this instruction manual!
●switch off the on/off switch before carrying out adjustment and repair work and ensure it
cannot be switched on again unintentionally!
●never work on parts or equipment still connected to the power supply! Exceptions to this
are only permissible according to regulations EN 50110;
●isolate the machine from the compressed air supply when carrying out maintenance or
repair work on pneumatic equipment!
Exceptions to this are only permissible for function checks;
●replace all safety covers after carrying out maintenance or repair work!

1 - 4
Safety
1.06 Danger warnings
A working area of 1 m must be kept free both in front of and behind the mach-
ine, so that easy access is possible at all times.
Never put your hands in the sewing area during sewing!
Danger of injury by the needle!
While setting or adjusting the machine do not leave any objects on the table
nor in the needle plate area! Objects may be trapped or slung out of the mach-
ine!
Do not operate the machine without take-up lever guard 1!
Danger of injury due to movement of the take-up lever!
Do not operate the machine without belt guards 2und 3!
Dange of injury by the rotating v-belt!
Do not operate the macine without finger guard 4!
Danger of injury by the needle!
Do not operate the machine without tilt lock 5!
Danger of crushing between sewing head and table!
Fig. 1 - 01
12
3
4
5

Proper use
2 - 1
2 Proper use
The PFAFF 1425 is a special single-needle high-speed lockstitch seamer with unison feed
and large sewing hook.
The PFAFF 1426 is a special two-needle high-speed lockstitch seamer with unison feed and
large sewing hook.
These machines are intended for sewing lockstitch seams in the textile industry.
Any use of these machines which is not approved by the manufacturer shall be
considered as improper use! The manufacturer shall not be liable for any dam-
age arising out of improper use! Proper use shall also be considered to include
compliance with the operation, adjustment, service and repair measures speci-
fied by the manufacturer!

3 - 1
Specifications
3 Specifications
3.01 PFAFF 1425, PFAFF 1426
Stitch type:.................................................................................................. 301 (lockstitch)
Model, PFAFF 1425: ..................................................................................................... CN
Models, PFAFF 1426: .......................................................................................... CN, CN8
Application: .................................................................................. medium-heavy materials
Needle sizes:...................................................................................................... 100 to 140
Max. thread size......................................................................................................15/3-ply
(synthetic, or other sizes of comparable thread types)
Effective dia. of balance wheel: ............................................................................... 80 mm
Fabric clearance: ...................................................................................................... 16 mm
Clear workspace width: ......................................................................................... 285 mm
Clear workspace height: ........................................................................................ 115 mm
Max. stitch length:
Model CN:.................................................................................................................. 6 mm
Model CN8:................................................................................................................ 8 mm
Noise level at workplace
at a speed of 2800 r.p.m. (2400 s.p.m), PFAFF 1425: .....................................≤78 dB ( A )
at a speed of 2800 r.p.m. (2400 s.p.m.),PFAFF 1426: .....................................≤80 dB ( A )
Noise measurement according to DIN 45635-48-A-1
Net weight of sewing head, PFAFF 1425: ..................................................... approx. 50 kg
Net weight of sewing head, PFAFF 1426: ..................................................... approx. 52 kg
Gross weight, PFAFF 1425: ........................................................................... approx. 58 kg
Gross weight, PFAFF 1426: ........................................................................... approx. 60 kg
Subject to alterations in design, weights and dimensions.
Maximum sewing speed
The maximum sewing speed depends on the material to be sewn, and thus on the top feed
stroke.
Top PFAFF 1426 PFAFF 1425
feed Max. sewing speed in s.p.m. at needle gauges: Max. speed
stroke in s.p.m.
6 mm 12 mm 20 mm 28 mm 40 mm
1 mm 3800▲3600▲3400▲3200▲3000 4000▲
2 mm 3400▲3200▲3000 2850 2700 3600▲
3 mm 3000 2850 2700 2500 2300 3000▲
4 mm 3000 2500 2300 2150 2000 3000
5 mm 2200 2100 2000 1900 1800 2200
6 mm 1800 1900 1800 1700 1600 1800
7 mm 1800 1700 1600 1500 1400 1800
▲ From 6 mm stitch length onwards the maximum speed is 3000 s.p.m.

Specifications
3 - 2
3.02 Possible work aids
-731/02.......................................................................................................... Edge trimmer
-900/81........................................................................................................Thread trimmer
-910/04.......................................................................................Automatic presser foot lift
-911/35..........................................................................................Backtacking mechanism
-918/29..................................Quick-change stepping control and stitch-length adjustment
-926/06..................................................................................Bobbin thread supply monitor

Disposal of Machine
4 - 1
4 Disposal of Machine
●Proper disposal of the machine is the responsibility of the customer.
●The materials used for the machine are steel, aluminium, brass and various plastic mat-
erials.
The electrical equipment comprises plastic materials and copper.
●The machine is to be disposed of according to the locally valid pollution control regula-
tions; if necessary, a specialist ist to be commissioned.
Care must be taken that parts soiled with lubricants are dispoed of separately
according to the locally valid pollution control regulations!

Transportation, packing and storage
5 - 1
5 Transportation, packing and storage
5.01 Transportation to customer's premises
Within the Federal Republic of Germany, complete machines (with table and motor) are
delivered without packing.
Machines without table (only sewing heads) and machines intended for exports are packed.
5.02 Transportation inside the customer's premises
The manufacturer cannot be made liable for transportation inside the customer's premises
nor to other operating locations. It must be ensured that the machines are only transported
in an upright position.
5.03 Disposal of packing materials
The packing materials of this machine comprise paper, cardboard and VCE fibre. Proper dis-
posal of the packing material is the responsibility of the customer.
5.04 Storage
If the machine is not in use, it can be stored as it is for a period of up to six months, but It
should be protected against dust and moisture.
If the machine is stored for longer periods, the individual parts, especially the surfaces of
moving parts, must be protected against corrosion, e.g. by a film of oil.

Explanation of symbols
6 - 1
6 Explanation of symbols
In this instruction manual, work to be carried out or important information is accentuated by
symbols. These symbols have the following meanings:
Note, information
Cleaning, care
Lubrication
Maintenance, repairs, adjustment, service work
(only to be carried out by technical staff)

Controls
7 - 1
Fig. 7 - 01
7 Controls
7.01 On/off switch
●Switch machine on or off by turning on/-
off switch 1.
Fig. 7 - 02
7.02 Keys on machine head
●The keys on the machine head are pres-
sed to set off certain functions.
Key 1: Reverse sewing or intermediate
backtack within the seam
Key 2: Raisei needle
Key 3: Activate pre-set top-feed stroke
(on machines with quick-change
stepping control) -918/29)
Diode on = high stroke
Diode off = low stroke
Key 4: Switch off backtack function for
one tack
Key 5: Activate pre-set stitch length (on ma-
chines with quick-change stepping
control -918/29)
Diode on = long stitch length
Diode off = short stitch length
Key 6: EMERGENCY key. presser foot
and needle are raised and the
machine switched off (diode on).
2
1 3 4 5 6
O
1

Controls
7 - 2
7.03 Pedal
0= Neutral position
1= Sewing
2= Raise presser foot
3= Trim sewing threads
For other pedal functions
please refer to the instruction
manual of the motor
manufacturer.
Fig. 7 - 03
0
1
23
7.04 Knee switch
●By operating knee switch 1 it is possible
to alternate between two pre-selected
feed stroke settings.
For the high stroke setting the
speed is reduced.
The function of the knee
switch can be changed; please
refer to the instruction manual
of the motor manufacturer.
Fig. 7 - 04
1

Controls
7 - 3
Fig. 7 - 05
7.05 Presser foot fixing key
●To fix the presser foot, raise it with the
pedal, then press key 1and release the
pedal again.
●To release the presser foot, raise it
briefly with the pedal.
Fig. 7 - 06
7.06 Stitch-length setting
●Feed regulator disks1 und 2are for
setting the stitch length.
●The maximum stitch length is set on
regulator disk 1and the minimum stitch
length on disk 2.
●To activate the pre-set stitch length
press key 5 (see chapter 7.02).
12
1

Controls
7 - 4
7.07 Reverse-feed control
●To sew in reverse, press reverse-feed
control lever 1.
7.08 Edge trimmer -731/02
Keep your hands away from the
moving knife! Danger of injury!
●Press key 1 to switch the knife drive on
or off.
Fig. 7 - 07
Fig. 7 - 08
1
1

Controls
7 - 5
Fig. 7 - 09
7.09 Secondary needle-thread tension
●To increase the needle-thread tension
dis-engage lever 1by pushing it to the
right.
1
Fig. 7 - 10
1
7.10 Setting quick-change stepping control -918/29
●The minimum stroke is set by turning
balance wheel 1.
The high stroke is set at the
works. It can be adjusted by a
mechanic.
(see chapter 11.04.12, top
feed stroke)