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MA_218D-TP-R_A4_181015_en
3.4.4
The leaf spring (2) regulates the bobbin thread tension.
Thread tension - bobbin thread (Fig. 7)
By turning the flat-head screw with catch (1), the leaf spring must be adjusted in
such a way that when the bobbin is inserted, and the thread is correctly pulled
under the leaf spring and the bobbin case is released, the latter, together with
the bobbin, drops slowly down. A slight pull on the thread might be necessary.
Fig. 7
3.4.5
It must be possible to draw the loop of the needle thread, taken up by the
shuttle, easily and without resistance through the bobbin case.
Bobbin case venting must set in once the loop has left the uppermost point of
the bobbin case and must have vented it when the loop is drawn between the
bobbin case and the shuttle bridge nose.
Setting the bobbin case venting (Fig. 4)
The moment of bobbin case venting can be adjusted by slackening the right nut
(4) on the needle lever bearing and turning the stop lever (3).
Retighten nut.
