Fig. 12 shows the third stage. The under thread has been enclosed by the needle thread, and the thread take-up lever is being raised to tighten the stitch.
Fig. 13 shows the stitch completed. The thread take-up lever has been raised to its highest point. Drawing the needle thread. together with the under thread. into the middle of the fabric. the two threads now being locked. The tension on the needle thread is regulated by the circular tension discs shown in the illustrations, and the tension on the under thread is regulated by a spring on the bobbin case.