The Siruba 747 Looper Upper and Lower are spare parts that are critical components of a serger or overlock sewing machine’s loopers mechanism. They are responsible for creating the loops that encase the raw edges of fabric and prevent them from fraying.
The Looper Upper and Lower typically consist of two metal pieces that are positioned above and below the fabric being stitched. They work in tandem to form the loop and secure it in place. The Looper Upper and Lower move in a synchronized motion, threading the thread through the fabric and forming the stitch.
If the Looper Upper and Lower become worn or damaged, they can cause the machine to produce poor-quality stitching or even break the needles. In such cases, it may be necessary to replace the Looper Upper and Lower with new ones.