If you’ve never sewn with knits before, you might be a little intimidated, but don’t worry! You can sew entire knit projects on your regular home sewing machine. Follow the guidelines below and you’ll be stitching up t-shirts and leggings in no time! (P.S. You can window shop our brand new knit collections Hello and Dress Shop, and read all about the cotton spandex jersey substrate in our previous post.)
THE RIGHT EQUIPMENT
When working with knit fabrics, you’ll want to use a ball point needle in your sewing machine. If you use the wrong kind of needle, you may see skipped stitches and snags in your fabric. Look for needles labeled “ball point” and/or “jersey”. (For our cotton spandex jersey, you don’t need the needles labeled “stretch”. Those are meant for super stretchy fabrics like swimwear and sport lycra.) Ball point needles actually have a slightly blunt tip, which pushes the fabric’s threads out of the way while sewing instead of piercing through them. This helps prevent those pesky runs. As far as needle size goes, a medium size 80/12 will be great for our cotton spandex jersey.
For hemming knits, you can get also get a twin needle. This will create the double line of stitching you’re used to seeing on ready-to-wear knits, which is usually made by a special machine called a coverstitch. There is a fabulous tutorial for how to hem with a twin needle on the Oliver + S blog.
What about presser feet? A normal presser for usually works ok, but you might find as you sew that the foot tends to push the upper layer of fabric forward faster than the lower layer, creating an annoying bubble. If this is happening, you can use a walking foot to help feed fabric through the machine more evenly. This will also help a lot if your machine is stretching out the fabric as it’s sewing and your seam looks ripply.
An additional fix for this problem is the lower the presser foot pressure. This refers to how hard the presser foot is holding onto the fabric as you sew. You want it to have a lighter pressure so that the stretchy fabric glides through more easily. Not all machines allow you to make this adjustment, but many do; look for a dial on the side, back or top of your machine towards the left side near the presser foot. You can also consult your sewing machine manual. (If you don’t have your machine’s manual, google for it – you can find a manual of pretty much any machine, new and old, as a PDF online.)
THE RIGHT STITCHES
Generally, the most important thing about sewing knits is to use a stitch that stretches along with the fabric. If you don’t, the first time you stretch a seam in your new tshirt while wearing it or putting it on, you’ll start popping threads and your tshirt will start falling apart. Not ideal.
The most basic stitch for seams is a narrow zig zag stitch. Select your machine’s zig zag stitch, then set the length to 2.5 and the width to 0.5. This is a great stitch for seams that aren’t going to be stretched a ton (ex. side seams, wider necklines).
Another option for seams is a mock overlock stitch. Your machine’s mock overlock stitch might look a little different, but the idea is that it’s mimicking the look of a serged stitch. Keep in mind that most likely, since the stitch is wider and centered under the needle, your seam allowance lines won’t be accurate any more. You’ll want to figure out where to sew by measuring out from the left-most place in the stitch. Once you sew the seam, you can trim the excess fabric close to the stitching.
A third option for seams is a reinforced straight stitch, also called a triple straight stitch. This stitch alternates two stitches forward and one backward, sewing a total of three times over each stitch. This is much stretchier than a narrow zig zag, so it’s good for seams that are going to be stretched a lot or have a lot of wear and tear. A warning, though – this is essentially one giant backstitch, so it’s not fun to unpick! Be careful when you’re sewing.
As far as finishing seam allowances – guess what! With cotton spandex jersey (and most other knits), you don’t have to! Because knits are, well, knitted, they don’t fray like wovens, so there’s no need to treat the edges in any way.
For hems, the biggest factor with stitch choice is how much your hem is going to stretch.
For hems that won’t really stretch, feel free to use a regular straight stitch like you’re sewing any old hem. An example would be the bottom hem of a full gathered skirt, like the Colette Moneta Dress hem. That hem will never have to stretch to accomodate wearing or putting on/taking off the dress, so it’s ok for it to not be stretchy.
If you need a slightly stretchy hem, you can use the narrow zig zag stitch described above. This might be used on the end of a looser fitting sleeve.
For a stretchy hem, a great option is a 3-step zig zag stitch. This sews in a zig zag pattern, but there are three little stitches in every zig and zag instead of one. This is nice and stretchy and would be great for the bottom hems of a pair of leggings that have to stretch around legs and feet.
You can also use a twin needle for hemming. Again, refer to this great tutorial on the Oliver + S blog for how to use a twin needle.
Also, feel free to experiment with the stretch stitches on your machine! You might find one you like better. Check your manual to figure out which ones are for stretch fabrics.
Here are a few extra tips and tricks that will make sewing with knits even better!
You’re going to want to get yourself some knit fusible interfacing. An example is Pellon EK130. Knit interfacing has a decent amount of cross grain stretch, so it will stretch along with the fabric. If your pattern calls for interfacing, this is the interfacing you’ll want to use, but you can also use it wherever you need a little extra stability. It’s great to use for hems. Just cut crossgrain strips of the interfacing the width of your hem, fuse along the edge of your fabric on the wrong side, fold, pin and sew. Sewing with the interfaced side up will help prevent the dreaded fabric bubble.
FOLDING ON GRAIN
When you fold the fabric to cut out a pattern, you want to make sure you are folding the fabric on grain, just like with woven fabrics. On the right side of the fabric, look for tiny vertical ridges or lines in the texture of the fabric. When you fold the fabric, the fold should be parallel to these little ridges. You don’t want to see the ridges twisting around the edge of the fabric, otherwise the fabric will feel twisty in the finished garment.
In general, working with knits is going to feel a little more fiddly than working with wovens. That’s ok! You can do it! Just go slow, use lots of pins, and remember to take a break if you need one.
Do you have any other tips for working with knit fabrics? If so comment below!