Upper Thread Tension - Necchi Supernova Instructions Manual

UPPER THREAD TENSION

Correct adjustment of the upper thread tension is imperative for
good sewing.
To function properly, the tension discs A, B, C, D (see Fig. 66)
must be kept very clean. It is not advisable to clean dirty tension
discs quickly by simply drawing a rag between them. Such a
procedure may shift the dirt to some hidden spot in the tension
mechanism and cause the tension discs to get out of contact with
each other. This occurrence, of course, will disturb the tension of
the upper thread and make sewing impossible.
To clean the upper thread tension, proceed as follows: unscrew
the thread tension knob first and then take off successively all
other parts of this mechanism (Fig. 66). All these parts shall be
cleaned thoroughly in a pan filled with cleaning fluid, and then be
wiped dry. Every part must be examined thoroughly with regard
to possible defects. The tension discs must not have rust spots on
their contact faces, or deep grooves worn into them by the
thread.
Defective tension discs must be corrected, if possible. Place the
contact faces of such repaired discs together, and check
whether they touch each other fully. If the tension discs, or any
other part of the tension mechanism, are defective beyond
repair, replace them with new parts. After having cleaned and
examined all parts of the tension mechanism, replace them in their
original positions. Then adjust the pressure upon the tension
discs until the correct tension has been obtained.
Note: To clean the upper tension mechanism, it is not
necessary to take it off completely; it is sufficient to unscrew the
knurled knob and remove all parts that are assembled on the split
stud " F ", as shown in Fig. 66.
While re-assembling these parts, make certain that check spring
"E" is set in notch " S " of the bushing " G "; also make certain that
the tension discs A, B, C and D are placed in the right order and
their faces are set as shown in Fig. 66.
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Copyright -2004