Brother LK3-B448E - Manual (Page 38)

31
LK3-B448E MARK II /BA-16
7. Correct use
Turn off the power switch before removing and replacing the bobbin case, otherwise the machine may
operate if the foot switch is depressed by mistake and serious injury could result.
q
30mm
CAUTION
7-5. Replacing the bobbin case and threading the thread
Pull the shuttle race cover q toward
you to open it.
Insert a new bobbin into the bobbin
case, and then pass the thread through
the slot
w
and pull it out from the
thread hole
e
. Check that the bobbin
turns in the direction of the arrow when
the thread is pulled at this time.
Pass the thread through the lever
thread hole
r , and then pull out ap-
proximately 30 mm of thread.
7-6 . Thread tension reference guide
w
e
r
Weaker
Stronger
Weaker
Stronger
w
q
7-6-1 . Lower thread tension
Adjust the thread tension to the weakest possible tension
by turning the thread tension nut
q until the bobbin case
will not drop by its own weight while the thread end com-
ing out of the bobbin case is held.
7-6-2 . Upper thread tension
Turn the tension nut
q
(main tension) to adjust the ten-
sion as appropriate for the material being sewn.
Furthermore, turn the thread nut
w (sub-tension) to ad-
just the remaining length of upper thread to 35 - 40 mm
when the thread take-up lever is not used.
weaker stronger
q
Upper thread tension (N)
Lower thread tension (N)
Thread take-up spring height
(mm)
#60 or equivalent
0.7 - 1.3
0.3 - 0.4
6 - 8
Thread
Pre-tension (N)
Needle
0.4 - 0.6
0.1 - 0.3
TQ
×
1#12
Thread take-up spring tension
(mm)