Underthread Puller For The Secure Seam Beginning - Duerkopp Adler 558 Service Instructions Manual

42.6 Underthread Puller for the Secure Seam Beginning

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In order that the underthread held in the thread gripper not be pulled
out of the thread gripper before the actual seam beginning through
rapid movement of the material support plate a suitable quantity of
thread must be pulled forward by the thread pulling lever 3.
The underthread gripper on the left clamping plate must thereby be set
so tight that the underthread 2 is subsequently pulled only out of the
underthread tension.
The quantity of underthread drawn forward must be so set,
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that the underthread, on the one hand, is held tight between the
hook and the needle plate bottom during the first stitch at the seam
beginning
–
on the other hand, it should also not be pulled out of the
underthread gripper at the first stitch.
The quantity of loose underthread at the hook required for this can be
seen in the illustration below.
Too great a quantity of thread can cause loose stitch pulling.
Too small a quantity of thread can lead to missing stitches at the seam
beginning.
ATTENTION !
When changing over from short to very long buttonhole lengths at the
length setting slide a correction of the thread quantity becomes
necessary.
The pulling forward of the underthread 2 occurs just before the
machine end position through latch 1 and thread pulling angle 4.
For setting see next page !
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