The smallest but most critical part of the seam
In a bag closing machine, the needle carries the thread through the bag fabric and forms the loop the looper catches. Even a slight bend or blunted point causes skipped stitches, thread breaks or torn bag fabric. That is why the sewing machine needle is the most frequently replaced part and should always be kept in stock.
How to choose a needle
- Machine model: the needle system (shank diameter, length, groove) is machine-specific; a different system will not fit or work properly.
- Size: larger sizes for thick thread and heavy bags, smaller for fine thread.
- Point type: points that part woven PP fabric without cutting it, or sharp points for paper bags.
Thread and needle match
The thread should sit in the needle’s long groove and pass freely through the eye. Thread too thick for the needle heats up and breaks; thread too thin does not form a proper loop and stitches skip. When you change needle size, review the thread; when you change thread, review the needle.
When to replace
- when stitches start skipping,
- when thread breaks or frays often,
- when the fabric tears around needle holes,
- when the needle has been dropped, bent or its point damaged.
In heavy use, renewing needles at set intervals rather than waiting for faults keeps seam quality steady. Send us your machine model and we will supply the right needles.
