657. Weaving

Shabbos 9:17

Weavers stretch the threads of the warp to the length and width of the fabric they are making. Two people hold them in place from either side. One person beats the warp threads with a rod to arrange them in their proper order without the woof. Stretching these threads is called “mounting the warp.” Tightening them is called “setting the warp.” Weaving is what occurs once one inserts the woof in between the warp threads.

Shabbos 9:18

A person is liable for mounting the warp, which is one of the primary categories of creative labor forbidden on Shabbos. One who beats the threads until they separate and then straightens them performs a subordinate labor of mounting the warp. The minimum amount for which one would be liable is a piece of fabric two fingerbreadths wide. Similarly, one would be liable for weaving two threads two fingerbreadths wide. This is so whether he just started weaving or added two threads to a garment that had already been started by someone else. If a person wove just one thread but it completed the garment, he would be liable. If a person weaves two threads three frames wide at the end of the cloth, he is liable. This is like weaving a thin belt three frames wide.