White 447 - Thread Tension Adjustment

To form
a
perfect
stitch,
the
tension
of
upper and
lower
threads
should
be
equal
so as to
lock
both threads
in the center
of
material
without
ioops
on
the
top or
bottom
of the
work.
A
B
Correct
tension
Upper
tension
too
tight
Lower
tension too tight
Upper Thread
Tension
When
the upper
thread
tension
is
too tight,
the
upper thread
lies
on
the
surface
of material.
When
the lower
thread
tension
is
too tight,
the
lower
thread lies
on the
under-surface
of
material.
Lower
Thread
Tension
Usually,
perfect
seams
can
be
produced
by
regulating
the
upper thread
tension.
To
increase
tension,
turn the
upper
thread
tension
regulator
clockwise,
and
to decrease,
counter-clockwise.
When
adjusting
upper thread
tension,
always
lower
down
the presser
foot,
as the tension
is
automatically
released
when the
presser
foot is
raised
—12—
Ordinarily,
it is
unnecessary
to
change
the lower
thread tension
but
there
are
some fabrics
that
require
a change.
To
increase
tension,
turn
small screw
on
the
tension
spring
of the bobbin
case
clockwise,
and to
decrease,
counter
clockwise.
As the
adjustment
of lower
thread
tension
is very
delicate,
do
not turn
the
small
tension
spring screw
in either
direction
more
than
about one
quarter
turn at
one
time.
L