JUKI LBH-1790 Instruction Manual
R
Computer-controlled, High-speed,
Lockstitch Buttonholing Machine
LBH-1790
INSTRUCTION MANUAL
NOTE : Read safety instructions carefully and understand them before using.
Retain this Instruction Manual for future reference.
E-No.03
40012734
R
MARKETING & SALES H.Q.
8-2-1, KOKURYO-CHO,
CHOFU-SHI, TOKYO 182-8655, JAPAN
PHONE : (81)3-3480-2357 • 2358
FAX : (81)3-3430-4909 • 4914
Copyright C
2003-2006
JUKI CORPORATION
All rights reserved throughout the world.
Please do not hesitate to contact our distributors or agents in your area for further information when necessary.
＊ The description covered in this instruction manual is subject to change for improvement of the
commodity without notice.
06 · 09 Printed in Japan (E)
IMPORTANT SAFETY INSTRUCTIONS
Putting sewing systems into operation is prohibited until it has been ascertained that the sewing systems in which these
sewing machines will be built into, have conformed with the safety regulations in your country.
Technical service for those sewing systems is also prohibited.
1. Observe the basic safety measures, including, but not limited to the following ones, whenever you use the machine.
2. Read all the instructions, including, but not limited to this Instruction Manual before you use the machine.
In addition, keep this Instruction Manual so that you may read it at anytime when necessary.
3. Use the machine after it has been ascertained that it conforms with safety rules/standards valid in your country.
4. All safety devices must be in position when the machine is ready for work or in operation.
The operation without the specified safety devices is not allowed.
5. This machine shall be operated by appropriately-trained operators.
6. For your personal protection, we recommend that you wear safety glasses.
7. For the following, turn off the power switch or disconnect the power plug of the machine from the receptacle.
7-1 For threading needle(s), looper, spreader etc. and replacing bobbin.
7-2
For replacing part(s) of needle, presser foot, throat plate, looper, spreader, feed dog, needle guard, folder, cloth guide etc.
7-3 For repair work.
7-4 When leaving the working place or when the working place is unattended.
7-5 When using clutch motors without applying brake, it has to be waited until the motor stopped totally.
8. If you should allow oil, grease, etc. used with the machine and devices to come in contact with your eyes or skin or
swallow any of such liquid by mistake, immediately wash the contacted areas and consult a medical doctor.
9. Tampering with the live parts and devices, regardless of whether the machine is powered, is prohibited.
10. Repair, remodeling and adjustment works must only be done by appropriately trained technicians or specially skilled
personnel. Only spare parts designated by JUKI can be used for repairs.
11. General maintenance and inspection works have to be done by appropriately trained personnel.
12. Repair and maintenance works of electrical components shall be conducted by qualified electric technicians or under the
audit and guidance of specially skilled personnel.
Whenever you find a failure of any of electrical components, immediately stop the machine.
13. Before making repair and maintenance works on the machine equipped with pneumatic parts such as an air cylinder, the
air compressor has to be detached from the machine and the compressed air supply has to be cut off. Existing residual
air pressure after disconnecting the air compressor from the machine has to be expelled. Exceptions to this are only
adjustments and performance checks done by appropriately trained technicians or specially skilled personnel.
14. Periodically clean the machine throughout the period of use.
15. Grounding the machine is always necessary for the normal operation of the machine. The machine has to be operated in
an environment that is free from strong noise sources such as high-frequency welder.
16. An appropriate power plug has to be attached to the machine by electric technicians. Power plug has to be connected to
a grounded receptacle.
17. The machine is only allowed to be used for the purpose intended. Other used are not allowed.
18. Remodel or modify the machine in accordance with the safety rules/standards while taking all the effective safety measures.
JUKI assumes no responsibility for damage caused by remodeling or modification of the machine.
19. Warning hints are marked with the two shown symbols.
Danger of injury to operator or service staff
Items requiring special attention
1
1
3
2
2
1 • There is the possibility that slight to serious injury or death may be caused.
• There is the possibility that injury may be caused by touching moving part.
3
2 • To perform sewing work with safety guard.
• To perform sewing work with safety cover.
• To perform sewing work with safety protection device.
3 • Turn OFF the power and perform “threading”, “replacement of bobbin or
needle”, “cleaning”, “adjustment” and “lubrication”.
i
FOR SAFE OPERATION
1. To prevent possible accidents due to electric shocks, neither open the cover of
motor electrical box nor touch the component(s) inside the electrical box.
2. Make sure of the needle entry after changing the pattern. Should the pattern protrude
from the work clamp check, needle interferes with the work clamp check resulting in
the danger of occurrence of needle breakage or the like. In addition, check that the
work clamp check which has been set corresponds to that which has been installed
on the sewing machine.
1. In case nothing is displayed in the operation panel even when the power switch is
turned ON, turn OFF the power switch and check the power voltage and phase.
2. To avoid personal injury, never put your fingers under the thread take-up lever, cloth
presser, cloth cutting knife, or needle when you turn the power switch ON or operate
the sewing machine.
3. To protect against possible accidents due to abrupt startup of the machine, turn
OFF the power switch before tilting the machine head or removing the motor cover.
4. To avoid personal injury, never bring your fingers, hair or clothing close to V belt,
cloth cutting knife or motor during operation, and never place anything on any of
these parts.
5. To avoid personal injury, never operate the machine with the motor cover, eye
protection cover, or any other safety devices removed.
6. To avoid personal injury, be careful never to allow your fingers to go inside the
machine when tilting or raising the machine head.
7. To prevent possible accidents due to electric shocks or damaged electrical
component(s), always turn OFF the power switch before connecting or disconnecting
the power plug.
8. During thunder and lightning storms, stop your work and disconnect the power
from the outlet to ensure safety and prevent possible accidents due to damaged
electrical component(s).
9. If the machine is suddenly moved from a cold place to a warm place, dew
condensation may result. If this occurs, be sure to confirm that there are no potentially
dangerous water drops in the machine before turning it on in order to prevent possible
accidents due to damaged electrical component(s).
10. In the event of a power failure, be sure to turn OFF the power to the machine to
protect against damaged electrical components.
11. This is a Class A product. In a domestic environment this product may cause radio
interference in which case the user may be required to take adequate measures.
ii
CONTENTS
蠢 . IMPORTANT SAFETY INSTRUCTIONS ....................................................................... 1
蠡 . SPECIFICATIONS ......................................................................................................... 1
1. Subclass ................................................................................................................................................1
2. Specifications........................................................................................................................................ 1
3. Standard sewing shape list.................................................................................................................. 2
4. Configuration ........................................................................................................................................ 3
蠱 . INSTALLATION ............................................................................................................. 4
蠶 . PREPARATION BEFORE OPERATION ..................................................................... 12
1. Lubrioation ..........................................................................................................................................12
2. Inserting the needle ............................................................................................................................ 12
3. Threading the needle-thread.............................................................................................................. 13
4. Threading the bobbin case ................................................................................................................13
5. Adjusting the bobbin thread tension ................................................................................................14
6. Installation of bobbin case................................................................................................................. 14
7. Installing the knife .............................................................................................................................. 15
蠹 . OPERATION OF THE SEWING MACHINE ................................................................. 16
1. Explanation of the operation panel switch .......................................................................................16
2. Basic operation of the sewing machine ........................................................................................... 18
3. How to use the pedal .......................................................................................................................... 18
4. Input of the presser type .................................................................................................................... 20
5. Performing pattern selection ............................................................................................................. 21
6. Changing needle thread tension .......................................................................................................22
7. Performing re-sewing ......................................................................................................................... 23
8. Winding bobbin thread .......................................................................................................................24
9. Using the counter ............................................................................................................................... 25
10. Using the initial value pattern ............................................................................................................26
11. Changing sewing data ........................................................................................................................27
12. Method of setting sewing data with/without edit .............................................................................28
13. Sewing data list ...................................................................................................................................29
14. Copying sewing pattern .....................................................................................................................35
15. Using pattern register key.................................................................................................................. 36
16. Using parameter register key ............................................................................................................ 37
17. Performing continuous stitching .......................................................................................................38
18. Performing cycle stitching .................................................................................................................40
19. Explanation of plural motions of knife.............................................................................................. 42
20. Method of changing memory switch data ........................................................................................43
21. Memory switch data list ..................................................................................................................... 44
蠧 . MAINTENANCE .......................................................................................................... 48
1. Adjusting the needle-to-hook relation ..............................................................................................48
2. Adjusting the needle thread trimmer ................................................................................................49
3. Adjusting the presser bar pressure ..................................................................................................50
4. Adjustment of the bobbin presser unit .............................................................................................50
5. Thread tension ....................................................................................................................................52
6. Cleaning the filter................................................................................................................................ 52
7. Replacing the fuse .............................................................................................................................. 52
蠻 . GAUGE COMPONENTS ............................................................................................. 53
1. Cloth cutting knife .............................................................................................................................. 53
2. Throat plate ......................................................................................................................................... 53
3. Presser .................................................................................................................................................53
衄 . ERROR CODE LIST .................................................................................................... 54
衂 . TROUBLES AND CORRECTIVE MEASURES ........................................................... 57
衒 . DRAWING OF THE TABLE ......................................................................................... 59
衙 . INITIAL VALUE DATA FOR EACH SHAPE TABLE .................................................... 60
iii
1.
IMPORTANT SAFETY INSTRUCTIONS
1) Never operate the machine unless the oiling tank has been properly lubricated.
2) Be sure to remove any dust from the hook or bobbin thread cutting knife section at the end of the day,
and check the amount of oil remaining.
3) Be sure to return the activating pedal to the home position after the machine has started to run.
4) A safety switch is installed so that this sewing machine can not be operated in the state that the machine
head is tilted. When operating this sewing machine, turn the power switch ON after setting the sewing
machine to the bed base properly.
2. SPECIFICATIONS
1. Subclass
Computer-controlled, high-speed, lockstitch buttonholing machine, LBH-1790, has the subclass machines below.
2. Specifications
Subclass
Major
application
Buttonholing
size
S
Buttonholing of cloth
such as men’s shirts,
blouses, work uniforms,
ladies' wear, etc.
Standard : Max. 5 mm
Special type part : Max. 10 mm
Knife size used :
6.4 to 31.8 mm (1/4' to 1-1/4')
Buttonholing sewing length
Standard : Max. 41 mm
Special type part : Max. 120 mm
K
Buttonholing of knits
such as knitted
underwear, sweaters,
cardigans, jersey, etc.
Sewing speed
Needle
Hook
Needle rocking drive
method
Feed drive method
Presser lifting drive
method
Lift of presser foot
Cloth cutting knife
drive method
Standard sewing
shape
Number of patterns
stored in memory
Motor used
Noise
Standard speed : 3,600 rpm (Max. : 4,200 rpm) (Max. : 3,300 rpm when dry hook is used)
DPX5 #11J to #14J
DP type full-rotary hook
Drive by stepping motor
Drive by stepping motor
Drive by stepping motor
14 mm (Optional setting available) Max. : 17 mm (At the time of needle up by reverse run)
By double-acting solenoid drive
30 kinds
99 patterns
Single phase 220/230/240 V, 3-phase 200 to 240 V, 1000 VA
Workplace-related noise at sewing speed
n = 4,000 min
Noise measurement according to DIN 45635-48-A-1.
–1
: LPA
≦ 83 dB(A)
− 1 −
3. Standard sewing shape list
(1) Square type
PANEL
DISPLAY
(7) Eyelet square type
PANEL
DISPLAY
(13) Semilunar square
type
(2) Round type
PANEL
DISPLAY
(8) Eyelet radial type
PANEL
DISPLAY
(14) Semilunar straight
bar-tacking type
(3) Radial square type
PANEL
DISPLAY
(9) Eyelet straight bar-
tacking type
PANEL
DISPLAY
(15) Semilunar taper bar-
tacking type
(4) Radial type
PANEL
DISPLAY
(10) Eyelet taper bar-
tacking type
PANEL
DISPLAY
(16) Eyelet semilunar
type
(5) Radial straight bar-
tacking type
PANEL
DISPLAY
(11) Semilunar type
PANEL
DISPLAY
(17) Eyelet round type
(6) Radial taper bar-tacking
type
PANEL
DISPLAY
(12) Round square type
PANEL
DISPLAY
(18) Square radial type
PANEL
DISPLAY
(19) Square semilunar
type
PANEL
DISPLAY
(25) Semilunar radial type
PANEL
DISPLAY
PANEL
DISPLAY
(20) Square round type
PANEL
DISPLAY
(26) Semilunar round
type
PANEL
DISPLAY
PANEL
DISPLAY
(21) Square straight bar-
tacking type
PANEL
DISPLAY
PANEL
DISPLAY
(22) Square taper bar-
tacking type
PANEL
DISPLAY
PANEL
DISPLAY
(23) Radial semilunar
type
PANEL
DISPLAY
(24) Radial round type
PANEL
DISPLAY
PANEL
DISPLAY
(27) Bar-tacking (28) Bar-tacking, right cut (29) Bar-tacking, left cut (30) Bar-tacking, center cut
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
PANEL
DISPLAY
− 2 −
4. Configuration
u
w
t
y
LBH-1790consists of the following components.
q Power ON/OFF switch
w Machine head (LBH-1790)
e Operation panel
r Control box (MC-601)
t Presser lifting pedal
y Starting pedal
u Thread stand device
e
q
r
− 3 −
3. INSTALLATION
WARNING :
To prevent possible accidents caused by the fall of the sewing machine, perform the work by two persons
or more when the machine is moved.
(1) Set-up of the table
r
!1
q
i
u
t
y
w
e
o
!0
1) Securely install control box w and power switch e on table q.
2) Securely fix the respective power cables of power switch e.
3) Pass four bed base fixed screws !1 through bed base r.
4) Set rubber cushions t to holes y (4 places) for fixing bed base and fix bed base r.
5) Fix head support bar u on table q.
6) After placing the sewing machine main unit on bed base r, connect pedal (right side) to pedal switch
o, and pedal (left side) to pedal sensor !0 respectively with connecting rods i which have been
supplied as accessories.
Adjust the positions of the pedals so that connecting rods i and control box w do not
come in contact with each other.
− 4 −
(2) Connecting the power source cord
• Voltage specifications
Power source specifications are indicated on the
voltage indication seal. (3-phase type only)
For other type machines, power source specifications
are indicated on the voltage caution seal and the
rating label.
Voltage caution seal
Voltage indication seal (3-phase type only)
Rating label
• Connecting single phase 200V, 220V, 230V and 240V
Light blue
Table
Control box
Green/Yellow
Brown
Light blue
Brown
Green/Yellow
Power switch
Connect the cord in accordance with the
specifications.
Plug
Power source cord
Brown
Light
blue
Green/
Yellow
AC200 V
AC220 V
AC230 V
AC240 V
GND
• Connecting three phase 200V, 220V and 240V
Table
Control box
Green/Yellow
Black
White
Red
Black
White
Green /
Yellow
Red
Power switch
1. Never use under the wrong voltage and phase.
2. When changing the voltage, refer to the item of "Changing the voltage of 100 /
200V".
Plug
Power source cord
White
Black
Red
Green /
Yellow
AC200 V
AC220 V
AC240 V
GND
− 5 −
(3) Changing the voltage of 100 / 200V
WARNING :
To prevent personal injuries caused by electric shock hazards or abrupt start of the sewing
machine, carry out the work after turning OFF the power switch and a lapse of 5 minutes or
more. To prevent accidents caused by unaccustomed work or electric shock, request the electric
expert or engineer of our dealers when adjusting the electrical components.
It is adaptable to the voltage of single phase 100V to 120V/3-phase 200V to 240V by changing the
voltage changeover connector mounted on FLT p.c.b.
(Caution) When the changing procedure is wrong, the control box will be broken. So, be very
careful.
Changing procedure of the changeover connector
1. Turn OFF the power source with the power
switch after confirming that the sewing machine
has stopped.
2. Draw out the power cord from the power plug
socket after confirming that the power switch is
turned OFF. Then wait for five minutes or more.
3. Remove the front cover.
4. Remove four screws fixing the rear cover of the
control box and slowly open the rear cover.
A. In case of using with 3-phase 200V to 240V
1
A
• Changing the changeover connector
Connect to 200V the 100/200V changeover
connector of FLT p.c.b. 1 located on the side
of the Box Side of the control box.
• Connect the crimp style terminal of AC input cord
to the power plug as shown in the figure.
B
C
WHITE
BLACK
RED
GREEN/
YELLOW
WHITE
BLACK
RED
GREEN/
YELLOW
WHITE
BLACK
RED
GREEN/
YELLOW
WHITE
BLACK
RED
GREEN/
YELLOW
WHITE
BLACK
RED
GREEN/
YELLOW
WHITE
BLACK
RED
GREEN/
YELLOW
(Plug side)
(Plug side)
(Plug side)
B. In case of using with single phase 100V to 120V
• Changing the changeover connector
Connect to 100V the 100/200V changeover
connector of FLT p.c.b. 1 located on the side
of the Box Side of the control box.
• Connect the crimp style terminal of AC input cord
to the power plug as shown in the figure.
(Caution) Securely perform the insulation
treatment to the red terminal which
is not used with insulation tape or
the like.
(When the insulation is insufficient,
there is a danger of electric shock or
leakage current.)
C. In case of using with single phase 200V to 240V
• Changing the changeover connector
Connect to 200V the 100/200V changeover
connector of FLT p.c.b. 1 located on the side
of the Box Side of the control box.
• Connect the crimp style terminal of AC input cord
to the power plug as shown in the figure.
(Caution) Securely perform the insulation
treatment to the red terminal which is
not used with insulation tape or the
like.
(When the insulation is insufficient,
there is a danger of electric shock or
leakage current.)
5. Check that the change has been performed without
fail before closing the rear cover.
6. Be careful that the cord is not pinched between
the rear cover and the control box main unit. Close
the rear cover while pressing the lower side of rear
cover, and tighten four screws.
− 6 −
(4) Installing the sewing machine main unit
1) Place hinge plates q and shaft bearings w-1
w-1 (rubber)
WARNING :
To prevent possible accidents caused by the
fall of the sewing machine, perform the work
by two persons or more when the machine
is moved.
(rubber) and w-2 (metal) in two places on the
head base and fix the hinge plates to the machine
head with setscrews e in two places.
When the rubber hinge and metal fitting
hinge are installed in reverse order, it is
dangerous since the sewing machine
shakes when it is tilted. So, be careful.
q
e
w-2
(metal)
(5) Tilting the sewing machine head
WARNING :
When tilting/raising the sewing machine head, perform the work so as not to allow your fingers to
be caught in the machine. In addition, to avoid possible accidents caused by abrupt start of the
machine, turn OFF the power to the machine before starting the work.
When tilting the sewing machine head, tilt quietly the
sewing machine until head support bar q comes in
contact with it.
1. Make sure that sewing machine head
support bar q is placed on the table
before tilting the sewing machine.
2. To protect fall-down, be sure to tilt the
sewing machine in a level place.
q
− 7 −
(6) Connecting the safety switch connector
w
q
Cord clamp
(7) Installing the hook oil shield plate
1) Connect safety switch connector q
with connector w located on the
machine head side.
q
e
w
(8) Installing the operation panel
q
Install hook oil shield plate q onto bed base e with
setscrew w.
Fix the sewing machine so that it does
not come in contact with hook oil shield
plate q when raising/tilting the sewing
machine.
Fix operation panel attaching plate q on the table
with woodscrew w and pass the cable through hole
e in the table.
w
e
− 8 −
(9) Connecting the cords
Perform the connection of the cords as shown in the figure below.
CN14
Sewing machine head
CN16
CN34
MAIN circuit
board
SDC circuit board
CN16
SDC circuit
CN14
CN44
CN14
q
board
CN42
CN37
CN38
CN39
CN41
Cord
clamp A
CN16
CN37
CN38
CN42
CN39
Operation panel
CN41
CN34
Electric bobbin winding device (optional)
CN44
1) Pass 4 cords (CN38, 39, 41, and 42) connecting
to the right side among the cords connecting to
MAIN circuit board through cord clamp A as shown
in the figure, and connect them to the respective
connectors. Connect CN37 to the connector
without passing through cord clamp A.
In addition, when using the electric bobbin winding
device (optional), similarly pass the cord of the
bobbin winding device through the cord clamp and
connect it to CN44.
2) Directly connect the cord from the operation panel
connecting to the left side of MAIN circuit board
to CN34.
3) Connect the cords connecting to SDC circuit board
directly to CN14 and CN16.
4) Fix the earth wire with the setscrew q.
− 9 −
(10) Managing the cord
1) Slowly tilting the sewing machine, check that the cords are not forcibly pulled.
2) Fix the cords with cord setting plate 1 as shown in the figure.
When you tilt the sewing machine, make sure that the sewing machine head support
bar 2 is placed on the table.
2
1
(11) Installing the eye protection cover
WARNING :
Be sure to attach this cover to protect the eyes from the disperse of needle breakage.
Be sure to install and use eye protection cover 1 and use the sewing machine.
When placed longitudinally When placed horizontally
1
1
Operator
Operator
− 10 −
(12) Fixing the temporary stop switch
The temporary stop switch has been in the state as shown in figure A at the time of delivery.
Loosen setscrew q and set the switch in the state as shown in figure B, and fix it with setscrew q together
with setscrew w supplied with the machine.
q
q
\
w
B
A
(13) Thread guide rod
Thread guide rod
(14) Installing the thread stand
w
Securely fit the thread guide rod so that two side holes
in the thread guide rod face the thread guide.
1) Assemble the thread stand, and set it in the hole
in the top right corner of the machine table.
2) Tighten locknut q to fix the thread stand.
3) When ceiling wiring is possible, pass the power
cable through spool rest rod w.
q
− 11 −
4. PREPARATION BEFORE OPERATION
1. Lubrioation
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
w
e
r
q
t
Detailed diagram of oil amount adjusting section
Oil pipe
e
w
Decrease
Oil amount
Increase
1) Lubricating oil to oiling tank
○
Fill the oiling tank with New Defrix Oil No.1 up to the level indicated by “MAX” q.
2) Adjusting the lubrication for the sewing hook
○
Adjust the amount of oil supplied to the sewing hook by loosening lock nut w and turning oil amount
adjusting screw e.
○
Amount of supplied oil is reduced when turning the screws e clockwise.
○
Fix the screw with lock nut w after adjusting the lubrication for the sewing hook.
○
When you first operate your sewing machine after set-up or after an extended period of disuse, remove
the bobbin case and apply a few drops of oil to the hook race. In addition, apply a few drops oil from oiling
hole r in hook driving shaft front metal t to soak the inside felt in oil.
2. Inserting the needle
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
q
A
Hold needle with its recessed part facing toward the operator side A,
insert the needle fully into the needle clamping hole, and tighten needle
setscrew q. Use a DPx5-(#11J, #14J).
When attaching the needle, turn OFF the power to the
motor.
− 12 −
3. Threading the needle-thread
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
!2
o
t
y
q
e
r
w
Cotton thread, spun thread
Synthetic filament thread
!1
u
i
!0
Pass the needle thread in the order q to !2 as shown in the figures.
The threading can be done easily by using the needle threader supplied with the machine.
Change the thread guide threading method according to the thread to be used.
4. Threading the bobbin case
Whip stitchPurl stitch
q
w
Bobbin
Rotating direction of bobbin and threading
1) Fit the bobbin so that it rotates in the direction of the arrow.
2) Pass the thread through thread slit q, then through under the tension spring w, again through thread
slit e, and pull the thread from r.
3) Threading at r for purl stitching is different from that for whip stitching. So, be careful.
Bobbin case
e
r
r
− 13 −
5. Adjusting the bobbin thread tension
w
q
Adjust the bobbin thread tension as given below when the bobbin thread is pulled up at the position where
thread slit q of bobbin case comes up.
To such an extent that bobbin case quietly comes down when holding
Purl stitch
Whip stitch
Turning tension adjust screw w clockwise will increase bobbin thread tension, and turning it counterclockwise
will decrease the tension.
Adjust the bobbin thread tension to lower for synthetic filament thread, and to higher for spun thread. The
thread tension is higher by approximately 0.05N when the bobbin case is set to the hook since idle-prevention
spring is provided.
0.05 to 0.15N
0.15 to 0.3N
thread end coming from bobbin case and shaking it quietly up and
down.
To such an extent that bobbin case barely comes down when holding
thread end coming from bobbin case and shaking it somewhat
strongly.
When bobbin thread tension is adjusted, check the needle thread tension setting of the
memory switch. (See P.44.)
6. Installation of bobbin case
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
q
1) Lift up and hold bobbin case latch lever between
two fingers.
2) Push the bobbin case into the hook so that it is
supported by the hook shaft q and then snap in
the latch lever.
Press the bobbin case until the predetermined
position is reached, and it will click.
1. If the bobbin case is out of the
predetermined position, it can jump
out from the hook to cause the needle
thread to tangle on the hook shaft.
Check to be sure that the bobbin case
is properly installed in the correct
position.
2. There is a difference in the shape of
bobbin case between the standard
hook and the dry one. They have
nothing in common with each other.
− 14 −
7. Installing the knife
WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
w
1 to 2 mm
q
Inch → mm CONVERSION TABLE
Knife size Indication of mm
1/4 6.40
3/8 9.50
7/16 11.10
1/2 12.70
9/16 14.30
5/8 15.90
11/16 17.50
3/4 19.10
13/16 20.60
7/8 22.20
1 25.40
1 1/8 28.60
1 1/4 31.80
1 3/8 34.90
1 1/2 38.10
When replacing the knife with a new one, perform as
follows.
1) Knife q can be easily removed together with the
washer when removing knife retaining screw w.
2) Adjust so that the knife, when lowered the knife
bar by hand, is spaced 1 to 2 mm away from the
top surface of the throat plate as illustrated in the
sketch. Then, be sure to place the washer and
tighten the knife retaining screw.
When the cloth cutting knife you have is indicated in
inch, set the cloth cutting length (knife size) in mm using
the inch → mm conversion table. (See P.29.)
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