There are three common ways of making fabric. Each one creates material with its own properties, which must be understood when sewing.
- Weaving, where warp threads go over and under woof threads (e.g. the denim used to make jeans).
Unless the threads are themselves elastic, woven fabric doesn't stretch. It is prone to fraying if not hemmed or cut with pinking shears.
- Knitting or crocheting, where each row of threads is looped over the threads in the next row (e.g.the cotton jersey used in T-shirts).
Knit fabrics stretch easily, and are best sewn with a serger rather than a sewing machine. Fine knits curl up, but do not unravel when cut with standard scissors.
- Felting, where fibres are matted together under pressure (e.g., well, felt).
Felts have very little tensile strength, and are rarely used for sewing, except as material for appliques.