LSc, known as the "felled" seam, is the strongest of all the seam types. Both top and bottom edges are folded in such a way that they interlock, leaving no raw edges. In 1896, Union Special Corporation designed the first adjustable folder for this seam for use on multiple needle machines producing stitch type 401. Today, the LSc seam is used in the construction of jeans, jackets, shirts, pajamas, coveralls, shorts, tents, and parachutes.
LSd, although seldom used for main seaming, is used to set most patch pockets, pocket flaps, pocket facings, and labels. To aid in the handling of the material, the edges of pockets, labels, etc., are occasionally creased prior to the seaming operation, giving greater uniformity and improved appearance.
LSe is formed by inserting a third piece between two folded plies. This seam allows an operator to join the shoulders or set the cuffs of a dress shirt in one operation. A 301 stitch is generally used on this operation since it looks the same on both sides.
LSf (a & b), used on shirts, dresses, and blouses for yoking operations, is usually joined with a 401 stitch (a) where the looper thread is completely hidden on the inside of the garment (b).