Query Related To Thread

Q. Why always Z - twist is used in sewing thread?

Ans: The direction of twist is important only for lockstitch seams. The movement of the hook in relation to the direction of the transport normally makes a Z-twisted thread necessary. If the transport ( during back-tack ) in running back or with a 2-needle machine on the left needle, a S-twisted thread would be better because the thread is more closed. For a multi-directional working on a lockstitch machine, e.g.for attaching pockets, the twist direction cannot be changed and therefore a high-twisted core spun is necessary so that the thread remains closed, even if the machine is running backwards.

Long time ago on a 2-needle machine a Z-twisted thread was also used on the right needle and a S-twisted thread on the left needle. Different twist direction has an influence on the lustre and the colour of the thread. Therefore, today the S-twisted thread does not exist anymore and has been replaced by the higher twisted core spun.

The S-twisted thread is typical for a hand sewing thread or for example bonded threads for overlocking or a bulked thread, which will be never used in a lockstitch machine.