Sewing Knits is Easy When you Follow a Few Rules
Contrary to many beginner-sewer rumors, sewing knits is easy! Once you’ve got the basics of woven garment construction down, you’ll find that knit fabric is even easier to sew, because you won’t need to add facings, finish seams, or worry too much about fit. However, there are a few things you need to do to make sure your garments look professional, and become your favorite things to wear. No more cookie-cutter t-shirts for you!
The first step, of course, is to make sure you’ve cut your knit fabric accurately, without stretching it out of shape, and with the stretch in the right direction. If you have a one-way stretch knit fabric, that stretch should go around your body, not up and down your body.
Here's our advice on cutting knit fabric.
Sewing knits with the correct needle type
Most knit fabric should be sewn with a ball point or jersey needle, which have rounded tips. The tip of the ball point needle gently pushes the fibers of the fabric apart to create each stitch. If your fabric is very fine or contains Lyrcra or Spandex, you could use a stretch needle instead.
If you are unsure of the best needle,
try our Needle Guide kit.
While sewing knits, the idea is to not break the fibers, and to not create holes that can cause a run (like in stockings or pantyhose).
To prevent the knit fabric from popping stitches, seams should stretch too. When you are sewing knits, use a slight zigzag stitch (.5mm) along with the average stitch length of 2.5mm -3 mm. No need to stretch the fabric as you stitch – the zigzag will allow the garment seams to move without snapping the thread.
If you have a classic old sewing machine that does not allow you to sew knits with a zigzag stitch, you can use a straight stitch to make stretchable seams, but you should stretch the knit fabric slightly as you sew. Set the machine to an average stitch length (2.5 mm – 3mm), then place one hand at the top of the fabric (behind the presser foot) and your other hand in front of the foot while guiding gently. Then stitch again, inside the seam allowance, using the same gentle stretching while sewing.
If you have a serger or overlock machine, you can simply serge the seams – that way the seams are finished as well as sewn – all in one step.
The Right Thread
It is best to use the thread that is compatible with all fibers – polyester or polyester wrapped cotton. Metallic threads are probably not a good idea, because they do not stretch. Wooly nylon thread works great if you have a serger and are doing rolled hems, or wrapped edge stitching (like on baby blankets). Need more info about
thread types and brands?
Seam Finishes - or Not
Most knits do not ravel – test the fabric though. Sometimes the fabric will have little fuzzies on the edge, and you may want to finish all seams just for a professional look.
Facings, even if called for on the pattern, can often be eliminated. Just turn the raw edges under and topstitch down. (No need to turn the edges under twice, as you would to create a finished edge on woven fabric).
For hemlines, using a double sewing machine needle will add a nice finishing touch without stretching the hem and creating waves. A double needle creates two straight rows of stitching on the right side, and a zigzag stitch on the wrong side. If you don’t want to purchase a double needle, two rows of top stitching side by side works just fine.
Of course, if you want waves on your hemline, you can always use fishing line to keep that wavy shape! Simply zigzag or serge over the fishing line to stitch the hem.
Are there seams where you don't want stretch?
There are some places you probably don’t want a seam to stretch too much – like the V neckline in a shirt, shoulder seams, or pocket edges. If your fabric is very soft, you might also want to stabilize the hemline.
Anyplace you don’t want seams to stretch or curl, you should add a seam stabilizer such as twill tape, organza ribbon, clear elastic, or a narrow piece of lightweight bias interfacing.
While sewing knits in the shoulder area, the piece of stabilizer should be sewn directly on the seam allowance (stitch through it), with a straight stitch. Using a piece of clear elastic (as in store bought garments) is quite common because it provides stability while maintaining some stretch in that area.
Hem and pocket edges can best be maintained by ironing fusible interfacing or stitching the stabilizer to the facing on the wrong side edge. Then turn facing to the inside, press, and stitch down with topstitching or a double needle.
For V-necklines, the stabilizer is best applied to the inside of the seam allowance only, then turned and topstitched down. Binding, however, is sometimes preferred.
Return from Sewing Knits to Sewing Kits