Sewing Lessons: Sewing with Knits: Shoulder Seams
Knits have got a bit of a bad rep. They are considered scary and difficult to sew. (Nothing could be further from the truth.)
This reputation as being only for experienced sewists** probably goes back to sometime in the 1960s when knit fabric became more commercially available, but everyone's sewing machine wasn't designed to sew knits.
**This misconception about sewing knits was so entrenched and universally believed that even a team of Vogue pattern designers expressed surprise at the ease of sewing knits while visiting a New York trade show booth for Jalie Patterns in the '80s where they witnessed Jeanne whipping up a knit garment on her home machine right before their very eyes!
But today's sewing machines are all built to handle knits with ease! You don't need a serger! Special knit stitches, adjustable tension settings for the thread and presser feet, easy to use walking feet, and ball-point, jersey and microtex sewing machine needles are easily available today, and make sewing knits simple.
In fact, sewing knits is EASIER than sewing wovens!
While there are a few tricks to know while actually constructing your garment, a knit garment is easier to fit, quicker to sew, and - best of all - sometimes you can even get away without having to hem it!
Modern sewing machines all have some variation of the knit stitches shown above. The main point to all knit stitches is to allow some "give" in the stitch so that the threads don't snap when the fabric is stretched.
Some are specialty knit stitches:
- The Lightning Stitch is so named because it looks a bit like a bolt of lighting. When the fabric stretches the lightning bolt straightens out but doesn't snap.
- The Straight Stitch is a "two stitches forward and one stitch back" kind of thing so that the stitches are overlapped and add strength to the seam.
- The Blanket Edge Stitch also has give to it, and is nice to use to finish off a hem edge to keep it from rolling and making a ridge in your garment.
Then there's every machine's zig-zag stitches.
- A Narrow Zigzag Stitch with a short stitch length and a narrow stitch width allows the same kind of straightening out as the Lightning Stitch but without an extra $200 to $400 of sewing machine!
Here's how they all behave when stretched. (Be kind, it's my first embedded video.)
It's a good idea to test the various stitch options before you begin your garment, just to decide which result you prefer. (I'll often use the lightning stitch for the seams and the straight stitch for any hemming or topstitching.)
Fiddle around with the tension settings and stitch length to see what works best for your project and the knit you've chosen. A ponte and a lightweight linen jersey are both knits, but they behave very differently!
Double check the seam allowance of the pattern. Many woven patterns use a 1/2" or 5/8" seam allowance to allow for seam finishings, but since knits don't ravel (another plus to sewing knits!) they tend not to need any seam finishing.
Typically, the seam allowance for a knit pattern is 3/8". (Some are 1/4" but I find that unbearably fiddly and usually fudge it to 3/16" instead. )
If you're ever afraid you're going to forget that you're using a different seam allowance mid-project, try using a magnetic seam guide or Post-It note to mark the new seam allowance.
Sewing the Shoulder Seams
If you think about it, the construction of most tops starts with the shoulder seams. Woven tops may sew darts or assemble princess seams first but really that's just assembling the front or back pieces, it's not actually constructing the top. You can see that you're actually making something when you've got the shoulder seams done!
T-shirt patterns almost always start by sewing the shoulder seams.
Fasten the shoulder seams together, using pins or Wonder Clips. I like to use clips when sewing knits, they seem to keep the fabric from sliding and bunching up better.
Sew the shoulder seams.
If you find that the fabric seems to bunch up between pins or clips - that a little hill of fabric is building up against the next pin or clip - this means that the bottom fabric is being moved by the feed dogs a bit faster than the top fabric. You can deal with this in one of four ways:
- Stop sewing and leave the needle down. Lift the presser foot and stretch the fabric slightly until the "hill" disappears. Lower the presser foot and continue sewing.
- Stretch the fabric slightly while sewing. This slight pull on the fabric will slow down the bottom fabric so that it is moving under the presser foot at the same rate as the top fabric.
- Switch to using a walking foot. Seriously, these things are super cool! A walking foot replaces the simple presser foot with a contraption that acts as another set of feed dogs for the top fabric. And they add a fun clunkety clunkety action to your sewing!
- Last option and not really recommended: Adjust the presser foot tension so that the top fabric is held more tightly against the bottom fabric and the feed dogs.
You'll end up with something that looks like this: