Hey there, sewing lovelies! Today I’m going to take you through how to sew with knit fabrics, regardless of what kind of sewing machine you’re using. This is a guide I’ve been meaning to write for a long time, and I’m so glad to have an opportunity to do so for the McCall’s Wrap Dress Sewalong. Having a serger is nice, sure, but you can still get great results with a regular ol’ sewing machine – I did so for many years until I bought a serger.
I’m going to cover the basic stitches in this post: straight stitch, zig-zag, and also using a serger. I sew on a Bernina 1005 and don’t have some of the fancy stretch stitches on newer models, so you may want to reference the manual for your machine to see if you have some other stitch options to use.
If you’re new to sewing with knits, I highly recommend sewing some test seams with the fabric you’ll be working with, to get an idea of what stitch length/width to use, and to become familiar with the characteristics of the knit fabric you’re using. In the samples for this tutorial, I used a contrasting thread so it would be easy to show what the stitches look like, but of course you’ll want to use a thread that matches your fabric best.
Tools of the Trade
Ballpoint needles are made for sewing knit fabrics. They have a rounded tip which prevents the knit loops from splitting and breaking. Universal needles are made for sewing either woven or knit fabrics, but may not provide the best results with knit fabric like a ballpoint needle would.
I use my regular zig zag foot for sewing with knits. I know some say that a walking foot is key for sewing with knits, but I’ve never had an issue.
Ok ready? Let’s grab some fabric and start making some test samples!
1. Straight Stitch
This was my preferred way of sewing knit fabric until I bought a serger – yes, you can sew with a straight stitch on knits!
The key to doing so is while sewing the seam, the fabric needs to be stretched gently in both directions, front and back – this will prevent the stitches from popping in high-stress stretchy seams like waistbands and necklines, or any type of seam that needs to stretch. In the photo above, if I had two hands available (which I couldn’t because of holding the camera!), you’d see that I’d be stretching both the front and the back of the fabric, with equal tension, as I sewed the seam through the machine. This builds stretch into the stitching, which you can see below:
The stitches look kinda tiny and scrunched in the finished seam. .
And now you can see the stitches expand as they stretch with the knit fabric. Easy-peasy and no popping! Oh yes, and make sure to sew double-stitched seams for extra security – about 1/4″ away from the original stitching will do
Looks pretty good from the outside, too, when stretched.
2. Zig-Zag Stitch
Zig-zag stitching is probably the easiest way to sew knits on a traditional sewing machine – the zig-zag stitch by nature builds-in stretch to the seam you’re sewing, no fabric-stretching necessary.
After stitching your seam, stitch 1/4″ away from seamline in the seam allowance, just like with the straight stitch above.
This is what the seam will look like when you’re finished with double-stitching the seam.
And here’s what your zig-zag seam will look like from the outside when stretched. The reason I don’t care for this type of seam is that no matter how small I make my zig-zag stitch, I can see the stitches from the outside. To each his own though, if you like how this seam looks then go for it!
3. Serger Seam
This is the easiest of the bunch! Hopefully you’re familiar with using your serger, but if not, it’s not hard to get started – I whipped up a tshirt the day I bought my machine without a problem.
I keep my serger set to “M” (which is standard) for the stitch width, and the stitch length I tinker around with until I get a good look when I stretch my seam from the right-side – between 2 and 3 works for most of the knits I sew. Not pictured here, but I also keep the differential feed at N.
Just like how we sewed double-stitched seams on the sewing machine, you’ll want to use two needles in your serger (ball-point needles of course) – this means four-thread serging. I first started serging garments with only one needle/stitched seam, but the extra security on a stretchy garment is really important, so ideally knit garments should be sewn with two needles.
Also, since I’m using two needles, I line my raw edge of my fabric up with the “L” or “Left Needle” mark to the right of the serger bed – this will give me an accurate 5/8″ seam allowance. If I was using only one needle, I’d line my raw edge up with the “R” mark.
Now serge away!! I love how fast sergers sew, it’s pretty gnarly. Do people even say “gnarly” anymore?
You should end up with a pretty, serged seam like the above, with even tension and the looper threads hugging the raw edge of the seam.
If my thread matched the fabric, you wouldn’t be able to see the stitches at all with the fabric stretched!
Those are the three basic ways I’ve sewn seams on knit fabrics for all of my knit garments. Working with knit fabrics can be intimidating at first, but the more familiar you become with handling the fabric and working it through whatever machine you use, you’ll wonder why you waited so long to try sewing with knits! It will revolutionize your sewing world.
Of course, there’s more to sewing knits than what I could cover in a single blog post. If you’re looking for even more info, I highly recommend the Colette Guide to Sewing Knits that came out last spring – it’s the book that I wished existed when I was figuring out how to sew knit fabric.