Singer 15-91 Instructions For Using Manual page 10

26
site the stop washer extension S, then push
the dial to compress the spring so that the
thumb nut can be turned onto the stud,
carefully guiding the pin in the thumb nut into
one of the holes in the numbered dial. Lower
the presser bar and turn the thumb nut A to the
left until it stops at "0."? Thread the tension and
pull the thread through the tension dises to test the
amount of tension at the '"O"' position. At this point
there should be a barely perceptible pull on the
thread to indicate that there is a minimum tension
which gradually increases with the turn of the thumb
nut to the right, providing a full range of tensions
from light to heavy within one revolution of the
thumb nut. If the pull is too strong for a minimum
tension, press in the numbered dial to disengage the
pin in the thumb nut from the dial and reset the pin
in one of the holes to the left of the previous setting.
This resetting of the pin will produce less tension at
zero. On the other hand, should there be insufficient
tension at zero, press in the dial and reset the pin
in one of the holes to the right of the previous set-
ting. Repeat this process until the desired minimum
tension is obtained.
If Correct Stitching is Not Obtained:
Using No. 50 thread in the needle and on the bob-
bin, adjust the needle thread tension as instructed
above. Then turn the tension thumb nut to'3" and,
with two thicknesses of thin material in the machine,
adjust the bobbin thread tension, as instructed on
page 23, until the stitch is correctly locked in the
material as shown in Fig. 18.
A wide range of materials and threads can now
be accommodated without further adjustment of
the bobbin thread tension.
27 28
Loosen the thumb screw in the round cover plate
at the back of the machine, turn the plate upward
and fasten by tightening the screw. Turn the bal-
ance wheel over toward you until the connecting
TO OIL THE MACHINE
If the machine is used continuously, it should be
oiled daily. If moderately used, an occasional oiling
is sufficient.
Fie. 25. Front View, Suowrne Ornine Points
Apply one drop of oil at each of the places indicated
by the unlettered arrows in Figs. 25, 27 and 28.
Fra. 26. Omine Ports ar THE Back or THE MACHINE
rod Z, Fig. 26 is at its highest position. Then apply
a few drops of oil through the hole in the top of the
machine to the wick which is retained in the cap
of the connecting rod, as shown in Fig. 26. Also
oil the other moving parts inside, turn the cover
plate down and fasten it as before.
Draw to the left the bed slide plate, and after
removing the lint and dust which may have accumu-
lated (see instructions on pages 31 and 32), apply
oil to the shuttle race A, Fig. 30. The slide should
then be closed