In the world of ready-to-wear, a coverstitch machine is usually used for creating neat hems with stretch. But you can still create that same look and functionality without a coverstitch, and even without a serger!
All you need is a twin needle, a type of forked sewing machine needle that lets you sew two rows of stitching at once. Twin needles come in multiple widths. The wide width (1/4″) will closely mimic the look of a coverstitch.
1. To start, finish the raw edge of your hem. You can use a serger to overlock the edge, or use your sewing machine’s mock overlock stitch or a zigzag stitch to finish. While this step is not 100% necessary, it helps to create a cleaner and more durable edge.
2. Turn the finished hem under and press into place. If possible, stabilize your hem with a product such as Wonder Tape (see note below). Lower the bobbin tension to prevent the rows of stitches from forming a raised channel.
3. Insert the twin needle and follow your sewing machine’s manual for threading it with two spools of thread. Stitch the hem in place with a straight stitch, catching and securing the raw edge beneath, just like a coverstitch. See The Colette Guide to Sewing Knits, pp.82-83 for tips on maintaining an even hem. The underside of the stitch will have a zigzag, allowing the stitches to stretch.
Sometimes hems on knits can get a little wavy when they’re sewn using the twin needle technique. This is usually because the fabric is being stretched a bit as it’s sewn. To help get a crisp hem, try using a wash-away stabilizing tape, such as Wonder Tape. Wonder Tape is adhesive on both sides, so it even holds your hem in place while you sew!
Apply the tape to the wrong side of the fabric near the raw edge. Remove the backing, turn the hem up, and use the tape to adhere it in place. The tape will keep your hem in place while you sew, minimizing stretch, but will wash away later. Another option is a fusible interfacing tape, such as Stitch Witchery.
Have you ever sewn a knit hem this way? What problems or challenges did you have? Any additional tips to share?