How to sew a hem?
A hem is sewn on a smooth fabric edge formed by turning the raw edge under itself and sewing it down. The process of hemming completely encloses the cut edge in cloth, so that it cannot unravel. Heavy material with deep hems may be hemmed with what is called a dressmakers hem. An extra line of loose running stitch is added in the middle of the hem, so that all the weight of the cloth does not hang from one line of stitching.