Singer 645 - Buttonhole Controls and Thread Tensions

BUTTONHOLE
REVERSE
STITCH
TUNER
CONTROLS:
ADJUSTING
THREAD
TENSIONS
Always adjust
the
upper
thread
tension with
the
presser
foot
down,
as
the
tension is
released
when
it is
raised.
To
increase the
tension
on
the
upper
thread,
turn
tension
control
to
the,
right.
To
decrease,
turn
to
the
left.
Before adjusting
the
tension
be
sure
that
the
machine
is
threaded
properly.
It
is
seldom
required
to
adjust
the
bobbin
thread
tension,
however, when
necessary
to change
bobbin
thread tension, turn
small
screw
on
side
of
the
bobbin
case
clockwise
to
tighten
, counterclock
wise
to
loosen.
When
both
tensions are
properly
balanced,
a
perfect
stitch
will
be
formed with
both
threads
interlock
ing
in
fabric
(A).
When
the
upper
tension
is too
tight,
the
bobbin thread
is
pulled
up
over
the
upper
thread
which
is
lying
flat
on
the
fabric
(B).
When
the
upper tension is
too
loose,
the
upper thread
forms
loops
over
the
bobbin
thread lying
flat
on
the
fabric
(C).
When
the
upper and
bobbin thread
tensions are
balanced
but
fabric
is
puckered
in
sewing
direction
on
sheer fabrics,
both
tensions
are
too
tight.
Loosen
both
tensions evenly.
It
is
recommended
to
adjust the
tension balance
under
medium
stitch
length. In
case
of
satin
stitching
for
buttonholes
and
em
broidery
shghtly loosen the
upper
thread
tension.
izuLrLr
r
S
The
tuner
is
for
the
adjustment
of
preset
right
buttonhole
side-
reverse
stitch
density,
while
it may
be
seldom
required
as
far
as
the
left
buttonhole
forward
satin
stitch
in
buttonhole
step
(1
(is
properly
set
by
the
stitch
length
control.
The
adjustment
is
made
by
screwdriver,
setting
the
stitch
selector
at
buttonhole
step
(3).
Turning
tuner
to
the
right
(+),
the
preset
reverse
buttonhole
stitch
density
is
increased
and,
to
the
left)—).
it
becomes rough.
0
lC)
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