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Welcome back to another lesson in the free Cucicucicoo Learn how to Machine Sew course for beginners! I’ve already shared some essential tips and instructions for sewing knit fabrics, but I didn’t get into detail about one of the best tools for sewing stretching fabrics. So today I’m going to show you how to sew knits with a twin needle!
Let me introduce you to the much-loved, yet much-feared, twin needle! There are all different types of twin needles (also called double needles), such as the universal twin needle (for regular woven fabric), the jeans twin needle (for jeans, obviously), and the stretch twin needle (for stretchy fabrics).
The twin needle is inserted in the sewing machine the same way as a normal sewing needle, but it has two points and eyes, instead of just one. It therefore takes two top threads at once. You usually use it to sew a straight stitch, but not always. The bobbin thread gets pulled between the two top threads, creating a zig zag under the fabric.
This double thread is often used for decorative effects, such as the double stitching on jeans. But today we’re going to use the stretch double needle to sew strechy fabric.
So, why is the twin needle so useful for stretch fabric? Well, have you ever tried sewing a stretchy fabric with a regular straight stitch? If you have, you’ll know that a straight stitch doesn’t stretch, which means that your sewn piece will not stretch and/or the thread will snap when you try to stretch the fabric.
That zig zagged bobbin thread, however, gives the stitches some stretch, as well as creating a very nice, clean and professional look, which the zig zag stitch, often used for stretch fabrics, does not.
Let’s talk size for a minute. Twin needle sizes have two parts. The second number is the same as for regular single needles, indicating the thickness of the needle. 90 is a normal mid-way size. 70 is for lightweight fabrics, and 110 for thick, heavy fabrics.
The first number, though, is specific to twin needles and indicates the space between the two needles. In the picture above, you can see the difference between 2/90, 3/90 and 4/90 double needles. The choice of this first number depends on the visual effect that you prefer. Needles that are closer together tend to create stronger stitching, however they can also create a tunneling effect, with raised fabric between the stitches, which isn’t very nice looking. I suggest have various sizes of twin needles on hand to try them all out.
Now let’s see how the twin needle works. It might seem daunting, however, once you learn how to sew knits with a twin needle, you’ll see that it’s actually quite simple and is a very useful technique to know!
Watch the video below, or scroll below it for a detailed explanation.
- Scrap stretch fabric (I’m using a scrap of 4-way stretch knit, meaning it stretches both horizontally and vertically.)
- 2.5/75 stretch twin needle*
- Two spools of polyester thread (I use Gutermann Sew All thread*) + a wound bobbin with polyester thread (I’m using three different colors to better show them for the tutorial.)
- Spool pin mount* (if your sewing machine doesn’t already have one)
Threading the sewing machine
Let’s prepare the sewing machine with the twin needle. You basically need to thread the machine twice, once with each top thread.
Insert the twin needle as you would with any other sewing machine needle. (top image)
Then insert the bobbin as you normally would. Make sure that the bobbin is wound with polyester thread. (bottom image)
Thread the machine with the first spool of thread. I am using the blue thread for this. Just put it on the regular spool mount and thread the machine as usual. Then thread it into the eye of the left needle, as shown by the arrow above.
Put the extra spool mount onto the bobbin winder (top photo), then put the second spool of thread on it.
Then thread the machine with this second thread, brown in my case. Each sewing machine is threaded differently. My Elna Lotus is unusual in that the regular spool of thread is to the left, not to the right. The thread goes around the circular piece indicated by the arrow in the top photo above. The second thread must also go around the circular piece but, as it comes from the other direction, it goes around it in the other way, counter clockwise.
Continue threading the machine right over the first thread and pull the tip of the thread through the eye of the right needle. (bottom photo above)
Now we need to fish up the bobbin thread as we would do with just one top thread.
To do this, pull the two top threads under the presser foot and hold them out to the side, lower. Lower and raise the needle once using the hand wheel, and gently tug at the top threads. You’ll see the bobbin thread (the red one above) pop up.
Pull all three threads under the sewing machine foot and towards the back. Now we’re ready to sew!
How to sew knits with a twin needle
Fold your knit fabric scrap against the fabric’s greatest stretch, put it under the presser foot, and lower the foot.
Now start sewing with the straight stitch at your sewing machine’s usual preset.
Look at that! Two parallel lines of stitching! Very nice!
On the bottom, you can see the bobbin thread zig zagging between the two top threads. This is what gives the stitch some elasticity.
It’s very important to note that you should ALWAYS test your twin needle before using it on a project. Each fabric, thread, needle and machine, and combination of them, will perform differently. My example above isn’t bad, however the bobbin thread could be more zig zagged, which would allow the fabric to stretch more.
For the above example, I used my usual preset of 3.0 stitch length and 4 top thread tension. When you want more stretch, though, you can play around with the stitch length, the top thread tension and the bobbin thread tension until the twin needle works perfectly, giving the most stretch possible.
I wanted more stretch, so I raised the stitch length to 3.5 mm and the top tension to 3. Let’s look at the result:
That’s a little better! Just keep adjusting until you find the best settings.
Do note that any type of stitching on a stretchy fabric will become wavy or bumpy. Just steam press the fabric and stitching, using a protective ironing cloth* to protect the fabric and polyester thread (which I’ve discovered can melt in contact with a hot iron!).
And that’s it! A lot of people are afraid of the twin needle, but once you know how to choose it, thread it and adjust the stitch, it’s actually quite easy and very useful!
So, now that you know how to sew knits with a twin needle, make sure you come back next week for an awesome project using the double needle!
If you liked this lesson on how to sew knits with a twin needle, check out the rest of the Cucicucicoo Learn to Machine Sew beginner’s sewing course! Don’t forget to share pictures of your work on Facebook or other social media with the hashtag #cucicucicoo or #cucicucicoopatterns!
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10 thoughts on “Tutorial: How to sew knits with a twin needle”
thanks for the good tutorial on twin needles. Have never been game to use them but I will now.
Hi Bianka! So glad that this tutorial has convinced you to try twin needles! Have fun!
Just checking if you use twin needles for seams on stretch fabrics please. Most of the tutorials seem to focus on hems. Thank you
Absolutely! This tutorial is specifically on using twin needle for stretch fabric. You just need to make sure you’re using twin needles for stretch fabric and good polyester thread!
I’m having problems with the twin needle on a light weight knit golf skort. When I practice on a woven scrap, stitching is fine, but when I change to knit it’s starts skipping stitches. I’ve adjusted stitch length and upper tension but just can’t make the stitching even and nice
Are you using a twin needle for knits/stretch fabrics and a good quality polyester thread? Those make a big difference when sewing knit fabrics. I also suggest using a walking foot. I always use one when sewing stretch fabrics.