How to use a twin needle – double needle sewing
I use my twin needles on my regular sewing machine mostly for hemming stretch fabrics, and therefore I prefer Klasse’ Twin Ballpoint Needles Size 80 – 4.0mm. The universal twin needles they sell at Joann sometimes work and sometimes don’t – like when I was sewing my tankini.
I’ve updated this post with a video that includes sewing with a twin needle. If you want to skip to that part, forward to 5:50 in the video below or on YouTube here.
I read several blog entries about using twin needles that were pretty helpful when I first started using these, but there were several things I had to discover on my own. So this is a summary of my best tips for sewing with twin needles.
- Buy ballpoint needles if you’re going anywhere near knits for this.
- Pay attention to the width (the mm number; 4mm in the picture above). Some extra wide-set needles won’t fit with the standard foot on vintage machines. I learned this the hard way.
- Leave loooooong tails when you start and stop sewing, and don’t backstitch (see below)
- Set your machine to a long (if not the longest) stitch, and use the straight-stitch, not zig-zag
- Give your stitching a tug every 6 inches or so if you’re doing a long hem to prevent puckering.
As I mentioned, I mostly use my twin needles to sew knit hems. Here is a step-by-step of how I do that:
First, replace your needle with a twin needle. Then put the thread and a bobbin of the same thread on your machine. Make sure thread is unwinding the same direction off both. Here are two configurations of what that might look like (please excuse the mismatched thread in the first picture).
Holding the two threads together, thread the machine as if you were only using one thread until you get to the needles, then separate the threads. Tug one to see if the left or right thread unwinds, then thread the corresponding needle. Iron your hem. If you HAVE to, pin it. But you don’t want to sew over the pins. Two needles = 2 x the chance you will hit a needle.
Sew with the top side of the hem up. I use my finger on the left hand to feel the seam as I feed the fabric. Remember to leave LOOOOONG tails before you start stitching.
Stitch around to where you started. Don’t backstitch or overlap your stitches. Leave long tails again before cutting. Give your hem a good tug. You’ll notice that the bobbin thread tails in particular may get a lot shorter. Thread your long tails through a needle, two at a time. Use the needle to pull the threads to the wrong side.
Knot all the threads on the wrong side before cutting.
Your stitches will look like this on the front.
And like this on the back. That zig-zagging of the bobbin thread is what gives the hem its stretch.