Singer 15-91 - NEEDLES AND THREADS

23
When the tension has been correctly set for aver-
age sewing, note the number at the indicator line Q,
so that the tension may be reset should it be altered
for special work or change in size of thread.
Toincrease the tension, turn the thumb screw A
gradually to the right (clockwise) until the required
tension is obtained. Each higher number denotes
increased tension.
To decrease the tension, turn the thumb screw
A gradually to the left (counter-clockwise) until the
required tension is obtained. Each lower number
denotes less tension.
TO REGULATE THE
BOBBIN THREAD TENSION
The tension on the bobbin thread is regulated by
the screw R, Fig. 11 in the tension spring on the
outside of the bobbin case. To increase the tension,
turn the screw R over to the right. To decrease
the tension, turn this screw over to the left.
When the tension on the bobbin thread has been
once properly adjusted, it is seldom necessary to
change it, as a correct stitch can usually be obtained
by varying the tension on the needle thread.
24
TO DISASSEMBLE THE
NEEDLE THREAD TENSION
NOTE:
The
needle
thread
tension,
Figs.
21
to
23
inclusive,
is
correctly
adjusted
at
the
fac-
tory
to
produce
the
complete
range
of
tensions
with
one
revolution
of
the
thumb
nut
A.
There
should
be
no
necessity
for
removing
or
taking
this
tension
apart.
However,
if
for
any
reason,
it
becomes
necessary
to
remove
the
tension,
proceed
as
follows:
Turn
the
thumb
nut
A,
Fig.
22
away
from
you
(toward
the
left)
until
it
stops
at
“0”
on
the
num-
Fre.
22.
Neepie
Tureap
Tension
DIsass—EMBLED
bered
dial
C.
Press
in
the
dial
to
disengage
the
pin
B
in
the
thumb
nut
and
remove
the
thumb
nut,
dial,
stop
washer
D,
tension
spring
F,
indicator
G,
the
two
tension
dises
H,
thread
guard
plate
L,
and
the
tension
releasing
pin
J,
as
shown
in
Fig.
22.
To
remove
the
pin
J
from
the
stud
N,
take
off
the
face
plate
and
tilt
it
so
that
the
pin
will
drop
out.
25
TO REASSEMBLE THE
NEEDLE THREAD TENSION
Replace the face plate, insert the tension releasing
pin in the stud, place the thread guard plate on the
Vig. 23. REassEMBLING AND REPLACING THE TENSION
stud, being sure that the lug M, Fig. 22 engages
the short recess P to prevent the plate from turn-
ing on the stud. Next, replace the two tension discs
H on the stud, having the flat thread-bearing sides
of the dises together. Replace the indicator G with
the large open side facing end of stud so that the
plus and minus signs will be readily seen from a
sewing position as shown in Fig. 23. Insert the ten-
sion spring F in the indicator so that the first half
turn F2 of this spring will straddle the lower half of
the tension stud. Guide the stop washer D onto the
stud so that the extension S will be above the ten-
sion stud as shown in Fig. 23.
NOTE: If the
spring and stop
washer are in cor-
rect position, the
extension S will
clear the first half-
coil of the spring, $ *
as shown in Fig. 24.
Next place the
numbered dial on
the stud so that the
numeral 2 is oppo-
£19048
Fre. 24