To hem the sweater, serge-finish the lower edge with a wide long stitch, adjusting the differential feed to a slightly plus setting. Turn up the hem 1 1/2" and topstitch with a twin needle.
If matching ribbing isn't available or if a ribbed finish isn't desired, bind the garment edges with self-fabric, contrasting knit fabric or ribbing.
Cut the garment neckline, sleeves and lower edge to the desired finished length.
Decide on the binding finished width, multiply by three, and add 1/2" to determine the binding cut width for a 3/4" binding, the cutting width is 2 3/4". Cut the binding with the greatest stretch along the fabric length. Note: The binding finished depth shouldn't be wider than 1".
For the sleeves and lower hem, join the binding ends to form a circle.
Serge-finish one binding lengthwise edge.
With right sides together and using a straight stitch, sew the binding to the sleeves and body lower edge, stretching the binding slightly as you sew. Note: The seam allowance should equal the finished binding width.
Turn the binding finished edge to the inside. From the right side, stitch in the ditch to secure.
To bind a neckline, sew only one sweater shoulder seam before adding the binding. Leave the binding in a strip, rather than joining it in a circle.
With right sides together, sew the binding to the neck, slightly stretching slightly around the curves so the binding will lie flat (9). Turn the binding away from the body and press the seam towards the binding.
Pin the remaining shoulder seam and make sure the garment will fit over the head. Straight stitch the shoulder seam and the binding ends together; finger-press the seam open.
Turn the binding finished edge to the inside. From the right side, stitch in the ditch to secure the binding in place.
Naomi Baker is a freelance serging and sewing consultant and is co-author with Gail Brown and Cindy Kacynski of The Ultimate Serger Answer Guide from Krause Publications.