50
21. Adjustment of thread check spring stroke
Note:
The tread check spring prevents the descending needle from piercing the slack needle thread.
The needle thread is slackened by the descending take-up lever.
Requirement:
Thread check spring 75 must keep the needle thread taut at least until the needle point enters the fabric
(Fig. 50).
The thread check spring must release the needle thread as soon as the lower edge of the needle eye enters
the fabric.
Check:
• Select stitch pattern „00“ for straight stitch.
• Set the stitch length at „6.0“.
• Place two pieces of fabric under the sewing foot.
• Sew a few stitches.
• Turn the handwheel and determine the end of the thread check spring stroke.
• Correct slackening of the needle thread takes place when it enters the needle eye not tautly but in a
loose curve.
Adjustment:
• Loosen screw 76.
• Turn thread check spring stop sleeve 77 until thread check spring 75 is in the correct position.
• Tighten screw 76.
Cross-check:
• Sew a few stitches and check as described under „Check“.
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