Singer 321C - Needle Thread Control; Tension Nut Adjustment; Thread Tension Adjustment

10
High Speed Overlock Machine | Instructions Manual and Parts List
3.6
Thread Tension
Adjustment
The thread tension should be adjusted according to the type and thickness of
cloth, thread, sewing width, stitch length and others. Therefore, the pressure on
the Tension Buttons or Thread Guides should be individually adjusted for each case.
Important
3.6.1
Tension Nut
Adjustment
The following adjustments are re-
latedtogure10.
Tension Nut 1:controls theneedle
threador theleftthreadin caseof
twoneedles.
Tension Nut 2: controls the thread
intherightneedle.
Tension Nut 3: controls the thread
intherightlooper
Tension Nut 4: controls the thread
intheleftlooper
Tension Nut 5: controls the thread
ofthesafetystitch.
Figure 10
3.6.2
Needle
Thread Control
Foralltypesofstitch504,512or514,
movedowntheguides‘1’ and‘2’.
Forthetypesofstitch503and505,
movethe guides ‘1’ and ‘2’ tothe
highestpoint.
Figure 11
The signal (+)
increases the tension
in the thread. The
signal (-) reduces the
tension of the thread.
Note