[Quick recap to set the scene. Our protagonist Susan loves to sew knits. She possesses no coverstitch machine. She thinks zigzag for hemming is okaaay, but it doesn't look ready-to-wear.]
TWIN NEEDLE: [Enters stage right, with a dramatic flourish.] Here I am! I will hem your knits beautifully, for just a few bucks and none of the table space you’d need for another machine!! I ROCK!
SUSAN: Oh twin needle, thank you!! You’re everything I ever wanted!
[TWIN NEEDLE and SUSAN exit stage right, into the sunset, and sew happily ever after.]
Not so much. In reality, my first (second, sixth…) attempt to use a twin needle resulted in a headache and a desire to hurl myself out of my first-floor sewing room window. I would have given up many moons ago, but I had developed a bit of a stubborn vendetta. (You’re shocked, I know.) I was acutely determined to figure this thing out. Flash forward about a year later, and I’ve discovered quite a few tidbits that can help. I love twin needle hemming now; it’s fast and easy, as sewing with knits should be!
Important note: I have a Brother PC-420 PRW sewing machine, so some of these notes may or may not be applicable to your machine. Regardless, they could give you points to ponder in your own twin needle exploration. Since this is a popular machine, I wanted to point it out.
The main issues I had with twin needle stitching boiled down to two things: skipped stitches & tunneling. There are a couple of other minor things that I address in the fixes below, but these were the worst of it.
Skipped Stitches. This happens when one (or more) of the needles passes through the fabric but doesn’t lock with the bobbin thread. Looks like this:
A few skipped stitches may not be the end of the world, but too many begin to look sloppy. Even more importantly, a line of stitching is far more likely to snap where there’s a skipped stitch. Just like a 5.0mm stitch isn’t as strong as a 2.5mm, when you have skipped stitches, the hem is weaker.
Tunneling. When the two rows of stitching pull towards each other, they create what looks like a loose pintuck. It’s kind of hard to capture a good picture of this, but hopefully this shadow helps to clarify:
As an aside, some folks do this intentionally to work pintucks! However, it’s nice to be able to avoid them if that’s not the look you’re going for.
So what to do? I did a lot of reading and researching and found a couple of helpful twin needle tips. (Make sure the threads are unwinding in opposite directions! Increase stretch with wooly nylon thread in the bobbin!) However, I wasn’t able to find anything that helped me get these two main issues in check. So I engaged in my own path of trial and error. Here are the results.
Stretch vs. Not. When I sew knits with a non-stretch twin needle, I get skipped stitches. Period. Some knits (less stable ones) make this happen worse than others, but it always happens at least a little. Stretch twin needles can be slightly harder to find, but find them you can, and since I really only use them for hemming, one “pair” lasts a long time.
Needle Position. This is one of those things applicable to the machine I use but may be for others as well. The Brother PC-420′s default needle position is left (instead of center), and to my knowledge there’s no way to change this programming. [Fortheloveofpeter, if you know how, please tell me.] I typically don’t have an issue with this, and I happily sew along in the left position until I find I need to move to the center for something. It took me a while to figure it out, but twin needle stitching is one of those somethings. Because the stitches aren’t centered between the feed dogs in the left needle position, I found the skipped stitches — and my control of the hem overall — to be much worse. Changing the needles to the center position helped a LOT.
Tension. Because my machine has automatic tension adjustment, it is rare for me to have to play with this setting, especially with a normal weight fabric and thread. However, I find that left to its own devices, the upper thread tension is too loose for a twin needle. See what happens? (bobbin thread is orange)
Sure we’re missing the bobbin zigzag prettiness, but the real issue is the strechability — the less pronounced that zigzag is, the less give the hem will have. Slightly tightening up the tension of the top threads will correct that. (I move it from 4 to 4.5-5, depending on the fabric.)
NOTE: I’ve sometimes read that loosening the tension will help the tunneling issue. That’s true, but it may also decrease the stretch. This won’t matter much in some cases, but in others — say, the hem of a slim-fitting maxi dress — it will matter a lot. I usually prefer to maintain the stretch of the hem and tend to the tunneling in another way.
Fusible webbing. My friend Miss Lulu gave me this tip when I couldn’t seem to get the tunneling whipped. She likes the crisp edge this provides for knit hems, and I have to say that it has really grown on me too. I don’t use it every time, but when I do, it sure makes those hems act like they’re new graduates from Miss Manner’s School for Well-Behaved Knits. I like the results with Stitch Witchery Ultra-Light. I press up the raw edge about 3/4″, then slip in a piece of the webbing (which is 5/8″), then fuse. Proceed with hemming. The finished hem may not stretch quite as much as it would without the webbing, but it will still stretch, and I find the trade-off worth it. It may feel a little stiff when first applied, but after a spin in the washer/dryer, I can hardly tell it’s there.
Distance of stitching line from raw edge of fabric. When I began twin needle hemming, I tried to get the two lines as close to the raw edge of the turned-under fabric as possible, sometimes even straddling it, like this:
With experimentation, I found that this sometimes exacerbated the tunneling. If you move just 1/8″ away from that raw edge, the flatness of the fabric helps keep tunneling to a minimum. If you’re working with a single knit, keep in mind that this edge will roll, so you may want to trim the excess if there’s a lot. (I would trim the excess in the below pic, if it weren’t just a sample…)
Stitching speed. Even if you normally like to see smoke coming off the spool, slow down a tad when using a twin needle. I’ve seen this reduce the skipped stitches somewhat, though many of the above tips helped me more.
Stitch length. If nothing is eliminating your skipped stitches or tunneling, try changing the stitch length. Decreasing it or increasing it slightly can help, depending on your fabric. My only caveat is not to make the length too long, since doing so will weaken the hem.
Lessen that pressure! This is not just applicable to twin needle stitching, but it is the single best tip I have for sewing knits. Also, it was a big selling point for me on my sewing machine — the ability to decrease the pressure of the presser foot. With lighter pressure, I never end up with wavy seams or hems, because the fabric isn’t being stretched as it goes under the presser foot. Huzzah!
Do you have any tips that make twin needle hemming a raving success on your projects? Do tell!
Update: I just finished my best knit hem ever, using these techniques plus some… Check out a new tip on my Cabarita post!