The mechanism of lock stitch formation (Stitch class 300) with illustration.

1. Principle of Lock Stitch formation:
1. The needle is penetrated into the fabric.
2. The needle reaches to its lowest position and the rotary hook is ready to catch the
needle thread.
3. As the needle moves upward from its lowest position, the needle thread forms a loop
which is caught by the point of the rotary hook.
4. The hook enlarges the needle thread loop & is guided around the bobbin thread.
5. The take – up lever tighten the stitch into the fabric & the fabric is fed forward.
6. The cycle repeats.

2. Figure: Mechanism of Lock Stitch formation