Brother BAS-341F User manual

BAS-341F
BAS-342F
Please read this manual before making using the machine.
Please keep this manual within easy reach for quick reference.
PROGRAMMABLE ELECTRONIC PATTERN SEWER
INSTRUCTION MANUAL

BAS-341F, 342F
i
Thank you very much for buying a BROTHER sewing machine. Before using your new machine, please read the safety
instructions below and the explanations given in the instruction manual.
With industrial sewing machines, it is normal to carry out work while positioned directly in front of moving parts such as
the needle and thread take-up lever, and consequently there is always a danger of injury that can be caused by these
parts. Follow the instructions from training personnel and instructors regarding safe and correct operation before
operating the machine so that you will know how to use it correctly.
SAFETY INSTRUCTIONS
1Safety indications and their meanings
This instruction manual and the indications and symbols that are used on the machine itself are provided in order to
ensure safe operation of this machine and to prevent accidents and injury to yourself or other people. The meanings of
these indications and symbols are given below.
Indications
DANGER The instructions which follow this term indicate situations where failure to follow the
instructions will almost certainly result in death or severe injury.
CAUTION The instructions which follow this term indicate situations where failure to follow the
instructions could cause injury when using the machine or physical damage to
equipment and surroundings.
Symbols
........................................This symbol ( ) indicates something that you should be careful of. The
picture inside the triangle indicates the nature of the caution that must be
taken.
(For example, the symbol at left means “beware of injury”.)
........................................This symbol ( ) indicates something that you must not do.
........................................This symbol ( ) indicates something that you must do. The picture
inside the circle indicates the nature of the thing that must be done.
(For example, the symbol at left means “you must make the ground
connection”.)

BAS-341F, 342F ii
2 Notes on safety
DANGER
Wait at least 5 minutes after turnin
g
off the
p
ower switch and disconnectin
g
the
p
ower cord from the wall outlet
before o
p
enin
g
the face
p
late of the control box. Touchin
g
areas where hi
g
h volta
g
es are
p
resent can result in
severe injury.
CAUTION
Environmental requirements
Use the sewing machine in an area which is free
from sources of stron
g
electrical noise such as
high-frequency welders.
Sources of stron
g
electrical noise ma
y
cause
problems with correct operation.
Any fluctuations in the power supply voltage
should be within 10% of the rated voltage for
the machine.
Voltage fluctuations which are greater than this
may cause problems with correct operation.
The
p
ower su
pp
l
y
ca
p
acit
y
should be
g
reater than
the re
q
uirements for the sewin
g
machine’s
electrical consumption.
Insufficient
p
ower su
pp
l
y
ca
p
acit
y
ma
y
cause
problems with correct operation.
The
p
neumatic deliver
y
ca
p
abilit
y
should be
g
reater than the re
q
uirements for the sewin
g
machine's total air consumption.
Insufficient
p
neumatic deliver
y
ca
p
abilit
y
ma
y
cause problems with correct operation.
The ambient temperature should be within the
range of 5 to 35 during use.
Tem
p
eratures which are lower or hi
g
her than this
may cause problems with correct operation.
The relative humidit
y
should be within the ran
g
e of
45% to 85% durin
g
use, and no dew formation
should occur in any devices.
Excessivel
y
dr
y
or humid environments and dew
formation ma
y
cause
p
roblems with correct
operation.
Avoid exposure to direct sunlight during use.
Ex
p
osure to direct sunli
g
ht ma
y
cause
p
roblems
with correct operation.
In the event of an electrical storm, turn off the
p
ower and disconnect the
p
ower cord from the
wall outlet.
Li
g
htnin
g
ma
y
cause
p
roblems with correct
operation.
Installation
Machine installation should onl
y
be carried out b
y
a qualified technician.
Contact your Brother dealer or a qualified electrician
for anyelectricalwork that mayneed to be done.
The sewing machine weighs more than 200 kg.
The installation should be carried out b
y
two or
more people.
Do not connect the
p
ower cord until installation is
com
p
lete, otherwise the machine ma
y
o
p
erate if
the foot switch is de
p
ressed b
y
mistake, which
could result in injury.
Hold the machine head with both hands b
y
two or
more
p
eo
p
le when tiltin
g
it back or returnin
g
it to its
original position.
Furthermore, after tiltin
g
back the machine head,
do not
p
ush the face
p
late side or the
p
ulle
y
side
from above, as this could cause the machine head
to to
pp
le over, which ma
y
result in
p
ersonal in
j
ur
y
or damage to the machine.
Be sure to connect the
g
round. If the
g
round
connection is not secure, you run a high risk of
receiving a serious electric shock, and problems
with correct operation may also occur.
Install the belt cover and the frame side cover to
the machine head and motor.
If usin
g
a work table which has casters, the
casters should be secured in such a wa
y
so that
they cannot move.
Be sure to wear
p
rotective
g
o
gg
les and
g
loves
when handlin
g
the lubricatin
g
oil and
g
rease, so
that the
y
do not
g
et into
y
our e
y
es or onto
y
our
skin, otherwise inflammation can result.
Furthermore, do not drink the oil or eat the
g
rease
under an
y
circumstances, as the
y
can cause
vomiting and diarrhoea.
Keep the oil out of the reach of children.

BAS-341F, 342F
iii
CAUTION
Sewing
This sewing machine should only be used by
operators who have received the necessary
training in safe use beforehand.
The sewin
g
machine should not be used for an
y
applications other than sewing.
Be sure to wear
p
rotective
g
o
gg
les when usin
g
the
machine.
If goggles are not worn, there is the danger that if
a needle breaks,
p
arts of the broken needle ma
y
enter your eyes and injury may result.
Set the needle to the needle u
p
sto
p
p
osition
before turning off the power.
If this is not done, the wi
p
er ma
y
strike the needle,
which might cause the needle to break.
Turn off the power switch at the following times,
otherwise the machine ma
y
o
p
erate if the foot
switch is de
p
ressed b
y
mistake, which could result
in injury.
• When replacing bobbin
• When not usin
g
the machine and when leavin
g
the machine unattended
If usin
g
a work table which has casters, the
casters should be secured in such a wa
y
so that
they cannot move.
Attach all safet
y
devices before usin
g
the sewin
g
machine. If the machine is used without these
devices attached, injury may result.
Do not touch an
y
of the movin
g
p
arts or
p
ress an
y
ob
j
ects a
g
ainst the machine while sewin
g
, as this
ma
y
result in
p
ersonal in
j
ur
y
or dama
g
e to the
machine.
If an error occurs in machine o
p
eration, or if abnormal
noises or smells are noticed, immediatel
y
turn off the
p
ower switch. Then contact
y
our nearest Brother
dealer or a qualified technician.
If the machine develo
p
s a
p
roblem, contact
y
our
nearest Brother dealer or a qualified technician.
Cleaning
Turn off the
p
ower switch before carr
y
in
g
out
cleaning, otherwise the machine may operate if
the foot switch is de
p
ressed b
y
mistake, which
could result in injury.
Be sure to wear
p
rotective
g
o
gg
les and
g
loves
when handlin
g
the lubricatin
g
oil and
g
rease, so
that the
y
do not
g
et into
y
our e
y
es or onto
y
our
skin, otherwise inflammation can result.
Furthermore, do not drink the oil or eat the
g
rease
under an
y
circumstances, as the
y
can cause
vomiting and diarrhoea.
Keep the oil out of the reach of children.
Maintenance and inspection
Maintenance and inspection of the sewing
machine should only be carried out by a qualified
technician.
Ask your Brother dealer or a qualified electrician to
carry out any maintenance and inspection of the
electrical system.
Turn off the power switch and disconnect the
power cord from the wall outlet at the following
times, otherwise the machine may operate if the
foot switch is depressed by mistake, which could
result in injury.
• When carrying out inspection, adjustment and
maintenance
• When replacing consumable parts such as the
rotary hook
Disconnect the air hoses from the air supply and
wait for the needle on the pressure gauge to drop
to “0” before carrying out inspection, adjustment
and repair of any parts which use the pneumatic
equipment.
If the power switch and air need to be left on when
carrying out some adjustment, be extremely
careful to observe all safety precautions.
Hold the machine head with both hands by two or
more people when tilting it back or returning it to its
original position.
Furthermore, after tilting back the machine head,
do not push the face plate side or the pulley side
from above, as this could cause the machine head
to topple over, which may result in personal injury
or damage to the machine.
Use only the proper replacement parts as
specified by Brother.
If any safety devices have been removed, be
absolutely sure to re-install them to their original
positions and check that they operate correctly
before using the machine.
Any problems in machine operation which result
from unauthorized modifications to the machine
will not be covered by the warranty.

BAS-341F, 342F iv
3Warning labels
Safety devices
Eye guard
Finger guard
Thread take-up cover
Belt cover , etc.
3
Be sure to connect the ground. If the ground connection is not secure, you run a high risk o
f
receiving a serious electric shock, and problems with correct operation may also occur.
12
The following warning labels appear on the sewing machine.
Please follow the instructions on the labels at all times when using the machine. If the labels have been
removed or are difficult to read, please contact your nearest Brother dealer.
1971S
Finger guard
Eye guard
Thread take-up cover
Belt cover

BAS-341F, 342F
CONTENTS
1. NAME OF MAJOR PARTS .................................................................................................................... 1
2. SPECIFICATIONS ........................................................................................................................................... 2
3. PREPARATION .................................................................................................................................................. 3
3-1. Before setting up .............................................................................................................................................................. 3
3-2. Positioning ......................................................................................................................................................................... 4
3-3. Tilting the sewing machine head .................................................................................................................................. 4
3-4. Connecting the ground wire ........................................................................................................................................... 5
3-5. V-belt tension ..................................................................................................................................................................... 5
3-6. Installing the foot switch ............................................................................................................................................... 5
3-7. Installing the spool stand ................................................................................................................................................ 6
3-8. Installing the programmer (option) ............................................................................................................................... 6
3-9. Adjusting the air pressure ............................................................................................................................................... 7
4. LUBRICATION...................................................................................................................................................... 8
4-1. Lubrication points ............................................................................................................................................................. 8
5. CORRECT USE................................................................................................................................................... 9
5-1. Selecting the needle and thread ...................................................................................................................9
5-2. Installing the needle and urnning the sewing machine..................................................................................9
5-3. Threading the upper thread ........................................................................................................................10
5-4. Winding the lower thread ............................................................................................................................11
5-5. Replacing the bobbin case and threading the thread .................................................................................12
5-6. Sewing conditions and thread tension ........................................................................................................12
5-6-1. Sewing conditions ....................................................................................................................................................12
5-6-2. Lower thread tension ...............................................................................................................................................13
5-6-3. Upper thread tension ...............................................................................................................................................13
5-6-4. Thread take-up spring height ...................................................................................................................................13
5-6-5. Thread take-up spring tension.................................................................................................................................. 13
5-6-6. Pretension tension ....................................................................................................................................................14
6. USING THE OPERATION PANEL................................................................................................ 15
6-1. Explanation of panel ....................................................................................................................................................15
6-2. Using the floppy disk ...................................................................................................................................................17
6-3. Using the program R/W (Read/Write) switch .............................................................................................................19
6-4. Using the TEST switch (Checking the sewing pattern) .............................................................................................20
6-5. Using the emergency stop switch ...............................................................................................................................21
6-6. Adjusting the sewing SPEED control .......................................................................................................................22
6-7. Changing the X-SCALE and Y-SCALE settings ........................................................................................................ 22
6-8. Using the bobbin thread counter ................................................................................................................................23
6-9. Using production counter ............................................................................................................................................24
6-10. Using single split mode ............................................................................................................................................. 25
6-11. Shifting a stitch pattern ..............................................................................................................................................26

BAS-341F, 342F
7. SEWING ....................................................................................................................................................................27
7-1. Before starting sewing....................................................................................................................................................27
7-2. Sewing operation ............................................................................................................................................................27
8. MAINTENANCE AND INSPECTION ........................................................................................29
8-1. Cleaning the shuttle hook .............................................................................................................................................29
8-2. Lubrication ........................................................................................................................................................................29
8-3. Draining the oil ................................................................................................................................................................30
8-4. Cleaning the control box air inlet port .........................................................................................................................30
8-5. Cleaning the eye guard .................................................................................................................................................31
8-6. Checking the needle ......................................................................................................................................................31
9. STANDARD ADJUSTMENTS ..........................................................................................................32
9-1. Adjusting the needle bar height....................................................................................................................................32
9-2. Adjusting the needle bar lift amount ...........................................................................................................................32
9-3. Adjusting the needle clearance ...................................................................................................................................33
9-4. Adjusting the driver needle guard ...............................................................................................................................33
9-5. Adjusting the shuttle race thread guide .....................................................................................................................33
9-6. Adjusting the movable knife .........................................................................................................................................34
9-7. Adjusting the presser foot..............................................................................................................................................36
9-8. Changing the presser foot lift .......................................................................................................................................37
9-9. Adjusting the wiper..........................................................................................................................................................38
9-10. Adjusting the needle up stop position ......................................................................................................................38
9-11. Checking the input sensor and DIP switch input ...................................................................................................39
9-12. Checking the input voltage .........................................................................................................................................40
9-13. Clearing all memory settings .....................................................................................................................................40
10. DIP SWITCH .....................................................................................................................................................41
10-1. Panel DIP switch functions ........................................................................................................................................41
10-2. DIP switches inside the control box .........................................................................................................................43
11. CHANGING SPECIAL FUNCTIONS AND
USING THE MEMORY SWITCHES ........................................................................................45
12. ERROR CODES ...........................................................................................................................................50
13. GAUGE PARTS LIST ACCORDING TO SUBCLASSES ...............................52
14. NOTES ON THE PROCESSING AND PRODUCTION
OF PLATE BLANKS.................................................................................................................................53
15. TROUBLESHOOTING ..........................................................................................................................54
16. OPTIONS ..............................................................................................................................................................58

1. NAME OF EACH PARTS
BAS-341F, 342F
1
1. NAME OF EACH PARTS
■BAS-341F
Emergency stop switch
Cotton stand
Programmer
Operation panel
Thread wiper switch
Power switch
Control box
Integrater
Solenoid valve
Starting pedal
Presser lifter pedal
1917S
■BAS-342F
Presser foot Work clamp
Feed plate
1918S

2. SPECIFICATIONS
BAS-341F, 342F 2
2. SPECIFICATIONS
Stitch formation Single needle lock stitch
Sewing machine Lock stitch, pattern tacking sewing machine (with large shuttle hook)
Maximum pattern size BAS-341F: 250X 150 mm, BAS-342F: 300 X 200 mm
Maximum stitch number 20,000 (one pattern)
Stitch length 0.1 - 12.7 mm
Maximum sewing speed 2,500 rpm (When stitch length is 3 mm or less)
Feed mechanism Intermittent feed, pulse motor drive
Shuttle hook Double hook (Standard hook is sold separately)
Needle DP X 5, DP X 17, MR
Data storage method 3.5 floppy disk 2HD/1.44MB, 2DD
Test function Operation test function provided for use with low speed drive
Safety devices Automatic stop function for activation in the event of misoperation realized with intermediate
stop function and safety circuits
Work clamp height Max.30 mm
Work clamp Unit work clamp (special order-separate work clamp)
Work clamp lift stroke 18 mm
Intermittent stroke 0 or 3 (Factory default) - 8 mm
Weights Machine head: 80kg,
Control box: 10 - 20 kg (depending on destination)
Power supply Single-phase 110V, 220V, 240V, 3-phase 220V, 380V, 400V, 900VA
Motor Three-phase 400 W induction motor
Air pressure 0.50 MPa 1.8 l/ min
Power table Use sitting or standing
Machine dimensions BAS-341F 1,200W X 1,220D X 860H mm (Sitting)-1,130H mm (Standing)
BAS-342F 1,200W X 1,270D X 860H mm (Sitting)-1,130H mm (Standing)

3. PREPARATION
BAS-341F, 342F
3
3. PREPARATION
CAUTION
Machine installation should only be carried out by
a qualified technician.
Contact your Brother dealer or a qualified
electrician for any electrical work that may need to
be done.
The sewing machine head weighs more than 200
kg. The installation should be carried out by two or
more people.
Do not connect the power cord until installation is
complete, otherwise the machine may operate if
the foot switch is depressed by mistake, which
could result in injury.
Be sure to connect the ground. If the ground
connection is not secure, you run the risk of
receiving a serious electric shock.
Hold the machine head with both hands by two or
more peple when tilting it back or returning it to its
original position. Furthermore, after tilting back the
machine head, do not push the face plate side or
the pulley side from above, as this could cause the
machine head to topple over, which may result in
personal injury or damage to the machine.
Install the belt cover and the frame side cover to
the machine head and motor.
If using a work table which has casters, the
casters should be secured in such a way so that
they cannot move.
Be sure to wear protective goggles and gloves
when handling the lubricating oil and grease, so
that they do not get into your eyes or onto your
skin, otherwise inflammation can result.
Furthermore, do not drink the oil or eat the grease
under any circumstances, as they can cause
vomiting and diarrhoea.
keep the oil out of the reach of children.
3-1. Before setting up 1. Install the Y driving shaft guard (1) to the rear of the
arm with the bolt (2) and the spring washer (3).
2. Install the guard (4) to the table rear cover (5) with the
bolt (6), spring washer (7), flat washer (8) and nut (9).
1919S

3. PREPARATION
BAS-341F, 342F 4
3-2. Positioning Decide the position for the sewing machine. Loosen nuts
of four level adjusters (1). Lower the level adjusters and
secure them with nuts (2).
Turning the level adjuster counterclockwise will raise its
height and turning it clockwise will lower it.
3-3. Tilting the sewing machine head
1. Remove screws (1) at the back of the work table, and
remove table cover (rear) (2).
2. Remove bolt (3).
The bolts are used to fix the machine in shipping.
Generally they are needless after removing them
keep them in another place.
3. Stand at the front of the table and slowly raise the
machine (4). Then lock it.
4. When returning the machine to its former position,
release lock (5). The gas spring will guide the machine
to its original position.
1920S
1921S
1922S
Gas spring

3. PREPARATION
BAS-341F, 342F
5
3-4. Connecting the ground wire
CAUTION
Be sure to connect the ground. If the ground connection is not secure, you run the risk of receiving a serious
electric shock.
Connection method for 3-phase power supply.
3-5. V-belt tension These should approximately 10 - 12 mm of slack when V-
belt is loaded at 9.8 N . To adjust, loosen the two nuts (1),
and shift the motor up or down.
3-6. Installing the foot switch Insert the connector of the foot switch (2) into the
connector (3) of the control box (1).
Red
White
Black
Yellow/Greeen
3-phase
power supply
Yellow/Green
0064Q
Connect to
ground
1923S
1924S

3. PREPARATION
BAS-341F, 342F 6
3-7. Installing the spool stand Install the spool stand (1) to the table.
3-8. Installing the programmer (option)
1. Install the programmer support (2) to the work table with the two screws (1).
2. Insert the programmer connector (4) securely into the left side of the operation panel (3).
(1)
(2)
1181S
[Flat]
(
2
)
(
1
)
(4) (3)
1182S 1183S
[Vertical]
(1)
(2)
0073Q
(1)

3. PREPARATION
BAS-341F, 342F
7
3-9. Adjusting the air pressure 1. Air pressure should be 0.5 MPa.
The air pressure can be adjusted by pulling up and
turning the control knob (2) on the integrator (1).
After adjustment is complete, push the control knob
(2) downward to lock it.
2. If water stands in the bottle of the integrator (1), turn
the drain cock (3) in the direction indicated by an arrow
to drain the water.
Note
Open the air cock (4) slowly.
1925S

4. LUBRICATION
BAS-341F, 342F 8
4. LUBRICATION
CAUTION
Turn off the power switch before starting lubricating, otherwise the machine may operate if the foot switch is
depressed by mistake, which could result in injury.
Be sure to wear protective goggles and gloves when handling the lubricating oil and grease, so that they do not
get into your eyes or onto your skin, otherwise inflammation can result.
Furthermore, do not drink the oil or eat the grease under any circumstances, as they can cause vomiting and
diarrhoea.
Keep the oil out of the reach of children.
Note
• Fill the machine with oil when the oil level is down to about one-third full in the oil sight glass.
If oil is not added and the oil drops below this level, there is the danger that the machine may seize during
operation.
• Be sure to let the machine operate for a while after adding the oil.
• Use only specified Brother oil (Nisseki Mitsubishi Sewing Lube 10N; VG10) for the machine oil.
4-1. Lubrication points
1. Fill the arm-side oil tank with oil.
(Fill the oil tank with sewing machine oil.) 2. Fill the bed-side oil tank with oil.
3. Add a drop of oil to the shuttle hook race. 4. If using the liquid cooling tank (1), fill it with silicon oil
(100 mm2/S).
1926S 1927S
1928S 1929S

5. CORRECT USE
BAS-341F, 342F
9
5. CORRECT USE
5-1. Selecting the needle and thread
Needle Thread Main application Different needles and threads are used for different sewing
applications.
Refer to the table at left for details on which needle.
5-2. Installing the needle and running the sewing machine
CAUTION
Turn off the power switch before installing the needle, otherwise the machine may operate of the foot switch is
depressed by mistake and serious injury could result.
DP X 5 #9 #100 - #60 Knitted wear
DP X 5 #16 #80 - #50 General clothing
DP X 17NY #19 #50 - #20 Denim
DP X 17 #21 #50 - #20 Denim
DP X 17 #25 #50 - #20 Leather•seat belts
Loosen the set screw (1), insert the needle (2) as far as
it will go so that the groove is facing toward you and
then tighten the set screw (1).
Simply press in on the pulley (1) to turn it by hand. To
turn the pulley, press lever (2) down.
• After turning the pulley by hand, be sure to press the
lever down to return the pulley to the normal
operating position.
■Installing the needle
1930S
■To turn the pulley by hand
1931S
Press
Turning Down

5. CORRECT USE
BAS-341F, 342F 10
5-3. Threading the upper thread
CAUTION
Turn off the power switch before threading the thread, otherwise the machine may operate of the foot switch is
depressed by mistake and serious injury could result.
■Thread the upper thread correctly as shown in the illustration above.
Note
• Turn the machine pulley and raise the thread take-up lever (1) before threading the upper thread.
(This will make threading easier and it will prevent the thread from coming out at the sewing start.)
• When threading the thread through the needle, allow a distance of approximately 40 mm between the needle hole
and the end of the thread. If the trailing length of the thread is too long, it may cause the thread to.
[When using cotton thread and spun yarn] 1932S
[With synthetic thread] [Threading in the upper thread breakage detector]
Real the thread from above once or
twice as the above figure. 1934S
1933S

5. CORRECT USE
BAS-341F, 342F
11
5-4. Winding the lower thread
CAUTION
Do not touch or place anything against any of the moving parts while winding the lower thread, otherwise
personal injury or damage to the machine may result.
1. Place the bobbin all the way onto the shaft.
2. Thread the thread as shown in the illustration at left,
wind the thread around the bobbin several times in the
direction of the arrow, and then press the bobbin
presser (1).
3. Turn on the power switch.
(The POWER indicator on the operation panel will
illuminate.)
4. Check that the needle is not touching the presser foot,
and then while pressing the STEP BACK switch (2),
depress the foot switch (3) to start the machine. Keep
depressing the foot switch (3) until the lower thread
stops being wound onto the bobbin.
Release the STEP BACK switch (2) after the machine
starts operating.
If you release the foot switch before winding is com-
pleted, depress it once more while pressing and hold-
ing the STEP BACK switch (2).
5. The bobbin presser (1) will automatically return to its
original position after a set amount of thread (80 - 90%
of the bobbin capacity) has been wound on.
6. Release the foot switch (3).
7. Remove the bobbin, hook the thread onto the knife (4),
and then pull the bobbin in the direction of the arrow to
cut the thread.
8. To wind more thread onto the bobbin, loosen the set
screw (5) and pull the bobbin presser (1) outward.
<< If the thread winds onto the bobbin unevenly >>
If the thread winds onto the bobbin unevenly, loosen
the nut (1) and turn the bobbin winder thread tension
stud (2) to adjust.
Note
If the thread winds on as shown in A, turn the bobbin
winder thread tension stud (2) clockwise; if it winds on
as shown in B, turn the bobbin winder thread tension
stud (2) counterclockwise.
1198S
(1)
(1)
(2)
A
B
0108Q
1199S
(2)
0107Q
(5)
(1)
0106Q
(4)
1935S

5. CORRECT USE
BAS-341F, 342F 12
5-5. Replacing the bobbin case and threading the thread
CAUTION
If the power switch needs to be left on when carrying out replacing the bobbin, be extremely careful to observe
all safety precautions.
The machine may operate if the foot switch is depressed by mistake, which could result in injury.
(ex. Continuing sewing from a stopping point)
1. Pull the shuttle race cover (1) forward and then open the cover.
2. Lift the bobbin case latch and remove the bobbin case.
3. Insert a new bobbin into the bobbin case, and then pass the thread through the slot (2) and pull it out from the thread
hole (3). Check that the bobbin turns in the direction of the arrow when the thread is pulled at this time.
4. Pass the thread through the lever thread hole (4), and then pull out approximately 30 mm of thread.
5-6. Sewing conditions and thread tension
5-6-1. Sewing conditions
Specifications For heavy materials For medium materials
Upper thread # 20 or equivalent # 50 or equivalent
Lower thread # 20 or equivalent # 60 or equivalent
Upper thread tension (N) 1.5 - 2.0 0.5 - 1.0
Lower thread tension (N) 0.2 - 0.4 0.2 - 0.4
Thread take-up spring height 8 - 10 mm 6 - 8 mm
Thread take-up spring tension(N) 1.5 - 2.0 0.4 - 0.6
Needle DP X 17 # 21 DP X 5 # 16
Normal sewing speed 2000 rpm 2000 rpm
The sewing conditions given in the above table may need to be changed depending on the article being sewn.
1936S 0110Q
(3) (2)
1202S
30 mm
(4)

5. CORRECT USE
BAS-341F, 342F
13
5-6-2. Lower thread tension 5-6-3. Upper thread tension
Set the lower thread tension to as weak a tension as
possible and so that the bobbin case drops by its own
weight when the end of the thread is held. Turn the
adjusting screw (1) to adjust the tension.
Note
If the lower thread tension is too weak, it may not be
possible to cut the lower thread properly during thread
trimming.
5-6-4. Thread take-up spring height 5-6-5. Thread take-up spring tension
Loosen screw (4) and turn the entire thread take-up unit to
adjust so that the height of the thread take-up spring is 8 -
10 mm
Turn the tension nut (2) (main tension) to adjust the tension
as appropriate for the material being sewn.
Furthermore, turn the thread nut (3) (sub-tension) to adjust
the remaining length of upper thread to 35 - 40 mm.
Stronger
Weaker
1938S 1939S
Stronger
Weaker
Higher
Lower
Adjust the thread take-up spring tension by turning the
tension stud
(
5
)
with a screwdriver.
0112S
(1)
1937S
Stronger
Weaker Weaker
Stronger