Baby Lock BL3-407 User manual

il::
"a

Pressure adiusting belt Spool stand
Thread take-uP lwer guard Handle type thread guide
Threed takeuP guide Face plate thread guide
Thread guide switch Needle thread tension adjuster
Thread tension adjuster
Thread take-uP cover thread guide
Upper knite Upper looper thread
tension adjuster
Thread finder
Throat Plate Lower looper thread
tension adjuster
Presser foot Flywheel
Lower knife
Side cover
Base plate
Rubber cushion
Knife cover
Needle bar thread gui * For safety, remove power supply plug after use'
Do not piace objects on the controller'
Needle clamP screw
thread guide
Lower looper thread take-up
Upper knife holder
fixing screw
Lower looper Lower looper thread take-up guide
Upper looper intermediary thread guide
looper thread take-uP
Looper soction

INTRODUCTION
Thank you for your purchase of our Baby Lock Model BL3407.
This machine not only works as two machines, both 3-thread and 2-
thread overedgers, but can sew a wide range of fabrics, from the thickest
to the thinnest materials.
This instruction booklet will be your guide to correct operation of Model
8L3407. Read this booklet carefully and you will be the real master of
your new machine.

Belt cover screws
(Figure 1)
Mount the motor correctly onto the machine
body as follows:
Remove the belt cover by loosening both belt
cover screws (Figure 1).
Mount the motor onto the machine body by
tightening the bracket f ixing screw while
setting the V-belt in place at the same time,as
shown in Figure 3. (The bracket fixing screw,
washer and V-belt are enclosed together in the
carton).
Belt tension will be most suitable when the
V-belt bends slightly under finger pressure
(see Figure 4). Make belt tension adjustments
by shifting the position of the belt tension
adjusting nut accordingly (Figure 4).
Re-attach the belt cover.
(Figure 4)
Belt tension adiustinq
fixing screw
uE@\
Bracket {ixing screw (Figure 2)
(Figure 3)
2

(Figure 5)
Controller
Connecting controller to motor
Put the connector in the terminal box socket,
as shown in Figure 5. Then put power inductive
plug into the power supply socket.
The machine runs faster as the controller pedal
is pressed down farther and slower as the pedal
is let up.
* For safety, be sure to remove the power
supply plug after use. Also be sure not to
place objects on the controller.
3
Terminal box

The one hand threading system of this machine ensures you the easiest possible threading.
You only have to thread correctly alonn the color-coded thread passages.
2-1 Prior to threading
(1) Setting of spool
Cheese (or cone) spool thread will be usually
used for this machine. Bobbin spool thread
is also available when held by *bobbin sup-
porter, as shown in Figure 7.
* available separately at order
(2) How to open knife cover and side cover
(Figure 8)
Pull the knife cover knob to the right and
then downward. Push open the side cover
to the left.
'Bobbin supporter
Bobbin spool thread
lFigure 7)
Push open tu the left.
Pull the knob to the right and
then downward.
Ch6€so spool thread
Fit 'baby net' (accessory) to cover
spool when you use synthetic
threads that are liable Io frczzle. (Figure 6l
4

(1)
(2)
(3)
l
I
i
2-2 For changing threads
Cut the thread (to be changed) near the
spool and tie the new thread to the re-
maining piece of thread on the machine,
as shown in Figure 9.
Lift up presser foot.
Lift tension adjuster knob so that it passes
the knot of linked thread smoothly, and
draw the thread till the knot comes about
10 cm past the presser foot (Figure 10).
Note: Special care must be taken when
changing "needle thread" :
Cut off the knot before it is rlrar,rrn
too near to the needle eye so as to
avoid possible bending of the neerlle
by pulling the knot caughr in rhe
needle eye (see Figure 1 1 ).
il
(Figure 9)
K nots
__'______-\--\
\n
| .-t-
li2
sr----
(Fisure 101
it
Needle eye
(Figure 111
5

2-3 For 3-thread overedging
This machine is pre-adjusted for 3-thread over-
edging and when unpacked will be found set
accordingly with three trial threads.
o Position of subsidiary looper and thread
guide switch
For 3-thread overedging, the subsidiary looper
and thread guide switch should be set in the
positions shown in Figure 12 and Figure 13.
respectivel y.
Handling guides for the subsidiary looper and thread guide switch
is charted on the back side of the knife cover.
Subsidiary looper
(Figure 12)
Thread guide switcl
=Red indicator
J,
2c
(Figure 131
6

(3)
a
(1)
(2t
How to set looper thread
Open both knife cover and side cover.
Set the upper looper thread according to the
'pink code.'
Draw out the thread about 1 0 cm away from
the presser foot'(see Figure 14 and Figure
15).
Set the lower looper thread in accordance
with the 'yellow code.'
The lower looper may be threaded most
easily in the following manner:
Turn the flywheel clockwise to bring the
lower looper to the far left.
Thread through the lower looper thread
guide @ and the lower looper first hole
@ while looking through the thread
f inder. Then bring the lower looper to the
far right and thread it through the lower
looper second hole @ .
Draw out the thread about 10 cm away
from the presser foot (see Figure 14 and
Figure 15).
Close both knife cover and side cover.
* A threading guide is charted on the back
side of the side cover.
Threading loopers
Thread finder
(for lower looper
th read )
\"(
t,E
ii
bi
'o/ :f(ffi
(Figure 141
7

. How to set needle thread
Correctly set the needle thread in accordance
with the 'blue code' referring to Figure 16 and
Figure 17. Then, be sure to pass the thread
through the needle eye from this side out into
the other side (hollow side). Draw out the thread
about 1 0 cm away from the presser foot.
Tension adjuster knob
Pass thread between the two plat€s, (Figure 161
')' batulot
(Frgure 17)
a

For switching from 3-thread overedging to
2-thread overedging, follow the instructions
below:
(1) Turn the flywheel clockwise to bring the
needle to the lowest position.
(2) Cut the upper looper thread as shown in
Figure 19. Roll up the end of the live thread
to be stopped at the upper looper thread
tension adjuster, as shown in Figure 20.
. Position of thread tension adjuster knob
When you carry out 3-thread overedging, the
bottom line of each tension adjuster knob should
be ranged within the blue strip zone. First, match
the bottom line with the center of the blue strip
zone as standard position.
2-4 Switching from 3-thread overedging to 2-thread overedging
Bottom line
Tension adjuster knob
(Figure 181
(Figure 19)
Roll up to stop
(Figure 2Ol
9

(3)
(4)
(5)
Push with a finger or a screw driver the head
of the subsidiary looper shaft and turn it
counterclockwise to make the subsidiary
looper tip fit into the upper looper hole, as
shown in Figure 21.
Turn the thread guide switch down to "2"
(red color). (The switch clicks when its red
indicator comes in line with the "2" marked
red on the thread.take-up cover.
Loosen the needle thread tension by turning
the adjuster knob till its bottom line comes
up and meets the center of the red strip
zone. Likewise, tighten the lower looper
thread tension by turning the adjuster knob
till its bottom line comes down and meets
the center of the red strip zone.
Subsidiary looper and upper looper
(Figure 21)
Push and turn counterclockwise
Thread guide srvitch
lFigure22l
Thread take-up cover
(Figure 23)
to

I
I
)
For switching from 2-thread overedging to 3-
thread overedging, follow the instructions below:
(1) Turn the flywheel clockwise to bring the
needle to the lowest position.
(2) With a finger or a screw driver push the head
of the subsidiary looper shaft and turn it
back clockwise till it stops, as shown in
Figure 24.
N.B. Do not stop the subsidiary looper
half way; it may cause problems if
left free.
(3) Turn up the thread guide switch to ,,3,,
(blue color). (The switch clicks when its red
indicator meets the ,,3'. marked blue on the
thread take-up cover, as shown in Figure 25.)
(4) Set the upper looper thread. as shown in
Figure 14 (Page 7).
(5) Tighten the needle thread tension by turning
the adjuster knob till its bottom line comes
down and meets the center of the blue strip
zone. Likewise loosen the lower looper
thread tension by turning the adjuster knob
till its bottom line comes up and meets the
center of the blue strip zone (see Figure 1g,
.Page 9).
Subsidiary looper
,clockwise
(Figure 24)
Thread guide sritch
indicator
(Figure 25)
2-5 Switching from 2-thread overedging to 3_thread overedging
1t

(1)
(21
I
\
2-6 Ghecking blank starting stitches
Before starting actual sewing, turn the fly-
wheel slowly clockwise by hand while lightly
pulling the ends of the threads together
with 'a finger pick, as shown in Figure 26.
Check if the threads are forming satisfactory
blank starting stitches.
Then, set the material to be worked on, and
start actual sewing.'
lmproper thread tension balance will cause
puckering and/or skip stitches. For good
thread tension adjustment, refer to the next
chapter, "Thread Tension Adjustment."
Cut the free end of the blank 'after-stitches'
to leave 2 - 3 cm from the end of actual
stitches just done. (Figure 27).
( Figure 261
'after-sti tches
lFisure2Tl
(3)
12

Upper looper thread
tension adjuster
-2\.E
\. I
'\ lml
/i
ii
il
There is a basic difference in the thread tension adjustment standard between 3-thread and 2-thread over-
;i?lif ;r'l;1* case, tension adiustment varies bv the tvpe and thickness of threads to be used and the mate-
Make thread tension adjustments accordingly with reference to "Application Reference for cloth, Thread
and Needles" (Page 2Sl , examining the seams coming out each time.
3-1 Adjustment for 3-thread overedging
The bottom line of each thread tension adjuster
knob should be ranged within the blue stripzone
on the adjuster dial cover (Figure 2g).
First, line up the bottom lines of all three tension
adjuster knobs with the center of the blue strip
zone. Then make minute adjustments of each
adjuster, checking the seams coming out with
each adjustment. Figure 30 shows ideal seams
sewn by 3-thread overedging. Tension adjuster knob
(Figure 281
ldeal soams
(Figure 30)
Needle threao
Figure 291
13

When lower looper thread laps round
When upper looper thread laps round When needle thread loosens
over th€ back
Needle thread
o
o
o
o
;F
J*P
o
o
o
o
b?
oii
)E
o
CL
o
o
3ej
o:
-ri
o
o-
o
Iod
O.o
Tighten upper looper thread tension
or loosen lower looper thread tension. Tighten lower looper thread tension
or loosen upper looper thread tension. Tighten needle thread tension or
loosen both upper looper thread
tension and lower looPer thread
tensi on. (Fisure 331
( Figure 31 l{Figure 32}
o
o
o
o
ooi
3-2 Adjustment for 2-thread overedging
The bottom line of each thread tension adjuster
knob should be r,anged within the red strip zone
on the adjuster dial cover (Figure 34)'
First, line up the bottom lines of the both ten-
sion adiuster knobs with the center of the red
stri P.
Then make minute adiustments of each adjuster,
checking the seams coming out with each adjust-
ment. Figure 35 shows ideal seams sewn by 2-
thread overedging.
Red strip
Bottom line
Tension adjuster knob (Figure 34)
t
ldeal seams When lower looper thr€ad laps round
over the back When needle thread laPs round over
the face
!o
T
o
o
o
o
o
J
!G
o
E
o
o
o
o
o
E
o
)
o
€
o
E
O
o
o
-
o
3
o
J
Tighten lower looper thread tension
or loosen needle thread tension. Tighten needle thread tension or
loosen lower looper thread tension.
,""*\-/
Y,*
\-i
-
(Figure 35) ( Figure 36) {Figure 37}
14

TzGL5IIIN(CIV/ ilil'r I
I.ltirdra I
I.IOIi
IT
Tighten the upper knife holder fixing screw
(Figure 38) when you are working on very thick
materials or making cross seams.
NOTES:
. Be sure to bring the upper knife down to the
lowest position when you tighten the upper
knife holder fixing screw.
o Be sure to return the upper knife holder f ixing
screw to normal when you work on materials
of normal thickness in the normal way (i.e.
when not making cross seams). Tightening
this screw will dull the work of the cutting
kn ives.
(Figure 38)
Upper knife holder fixing screw
The presser foot pressure is pre-adjusted for
materials of medium (standard) thickness. Adjust-
ment is necessary only when you work on very
thin or very thick materials.
Accordingly, sew thinner materials with less pres_
sure and thicker materials with more pressure. How to adjust presser foot pressure
Standard (level of machine top)
t5

Use DC x 1 needles of No. 7 - No. 14, or Schmetz
621 needles of the coiresponding sizes.
To replace the needles. follow the instructions
below:
(1) Turn the flywheel to bring the needle bar
to the uPpermost Position.
(2) Loosen the needle clamp screw and remove
the old needle.
(3) Put the tip of the new needle in the hole of
the throat plate, and then the head of the
needle into the needle bar hole all the way
to the end.
(a) Be sure to line up the hollow of the needle
directly with the other side when you
straight face the machine (Figure 41).
* Be careful not to mistake the thread
guide groove of the needle for the hollow
of the needle (see Figure 41).
(5) Tighten the needle clamp screw firmly while
holding the needle in correct direction with
Your fingers.
Hollow
( Back )
(Figure 41)
\l (-
'\f
,\l
t
(Figure 40)
16

i
i
l
(1) Loosen the feed regulator screw with the
heart-shaped driver (accessory ) wh ile h olding
the flywheel tight with your right hand.
Turn the feed regulator dial to select the
stitch length (feed pitch): Stitch length is
longer as the number on the dial increases
and shorter as it decreases.
Tighten the feed regulator screw firmly after
selecting the dial.
(2t
(3)
lFigwe 421
-i ,,-- -- Feed regulator
I /t ,/-;\ dial
, ,'//slF-
' ,/ ' - -dX Graduation
, ,Z -,t ..t \ \ rnorcaror
O f S/6..,."suru,o) {i";;-
v/
\ --'l (Figure 43)
Heart-shaped
17

This machine is pre-set at the overedge bight of
3.5 mm. which is standard. The bight can be
varied easily from 2.5 mm to 5 mm as desired.
To change the bight width, refer to Figure 44
and follow the instructions below:
(1) Turn the flywheel clockwise to bring the
needle to the upper most Position.
(2) Open both the knife cover and side cover.
(3) Push the upper knife holder with a finger
and turn the knife holder knob clockwise
to bring the knife blade 180" out of work
position.
(4) Loosen both lower knife holderfixing screws
to move the holder 2 - 3 mm to the right.
(5) Loosen the bight adjusting screw (Figure 46) to re-set the throat plate tongue (Figure 45) according to
the desired new bight width, which can be selected freely at any length within the range of 2.5 mm -
5 mm.
The bight width will be guided by the bight reference points on the throat plate edge line, as shown in
Figure 46 - 48.
A bight of 2.5 mm is obtained when you remove the plate tongue and do not use it'
(6) Set the lower knife holder back in place and tighten the lower knife fixing screw firmly.
Be sure, then, to make the level of the lower knife tip even with the surface level of the throat plate.
(7) Return the upper knife to its normal place'
* After bight adjustment, by turning the flywheel slowly by hand, make sure that the upper looper
does not hit other Parts.
(Figure 45) (Figure 46) (Figure 471 (Figure 48)
H
@H
@r3.Q
H
sH
G
1A