Finishing sweaters should be the easiest part. It’s the end, the home stretch, so to speak. But sewing the sides of the sweater together by hand can be a daunting task for knitters. The sweater pieces have a tendency to stretch and cause uneven seaming. Use a sewing machine or a serger to finish the job. With the right needle, stitch, thread and tension, the knits will seam together easily. This technique would also be useful for projects that use old sweaters to create new items such as a bag or hat.
Wash your sweater piece(s) in the gentle laundry detergent by hand. Knits can draw up after washing; preshrink the sweater so it does not draw up after sewing. Use a knit soaking wash as an alternative to detergent. Gingerly wring the sweater to release the water. The sweater should not be dripping excess water.
Place a towel on a flat surface. Spread the sweater out and let it air dry.
Turn the sweater inside out and place the open ends right sides together. Pin the seam together, keeping the pieces of sweater as flat as possible.
Thread your machine with a poly/cotton blend thread in a matching color. Insert the needle. Use a 75/11 needle for a medium-weight knit. Use a 90/12 for a heavier knit and a universal needle for a boucle or textured knit. A stretch needle is used for light-weight, smooth knits.
Stitch the seams using a zigzag stitch with a medium length such as 2.0 millimeters long by 2.0 millimeters wide. This will help the seams stretch with the knit. If you have a serger, use a 3 thread overlock stitch. Set the serger to have a balanced tension.
Finish the edge of the seam with a 2.0 millimeter long by 3.5 millimeter wide zigzag stitch. Run the stitches over the edge of the sweater to the right of the seam stitch. It is meant to keep the edges from unraveling. Use a blanket edge or overlock stitch on a regular sewing machine. On a serger, stitch a two or three thread stitch to finish the edge.
Flip the sweater inside out.
Do not stretch the sweater as you sew. Gently guide the knit through the machine.