If you are sewing knits and want a professional-looking hem, then consider learning how to use a twin needle. Twin needles can also be called double needles and are simply 2 needles joined together with one shank at the top. Once you are confident sewing knits and getting great results, it will open up a whole new world! The twin needle is also used for pin tucking and other decorative purposes in woven fabrics.
Look at most of the t-shirts in your cupboard and you will notice 2 neat, parallel rows of stitching on the bottom hem and sleeves. While this is done on a commercial coverstitch machine, you can get a nearly identical look with a twin needle and your regular sewing machine!
You can also learn how to use a twin needle for finishing the elastic in the legs or neck when sewing leotards.
Nearly all modern, domestic sewing machines can sew with a twin needle so you don’t need a fancy machine to get these professional-looking hems.
So are you ready to start learning how to make a beautiful twin needle hem?
Table of Contents
What is a twin needle used for?
A twin needle or double needle is used to produce two rows of parallel stitches on top with zig-zag looking interlocked stitches underneath. In woven fabrics, it is purely decorative but in stretch fabrics, it creates an attractive hem that will not break when stretched.
If you haven’t sewn stretch fabric before, it is important to mention that all your seams and hems need to stretch a similar amount to your fabric, otherwise the stitches will break. This is especially true for tighter fitted clothing. You don’t want to end up with holes in your seams!
Further Reading: How to sew stretch fabric
How to Use a Twin Needle (Double Needle)
Twin Needle Supplies
- Scrap fabric or your project to hem.
- Twin needle – Popular brands include Schmetz, Birch and Singer.
- Your zig-zag machine foot. This is important because the opening in a regular foot is generally not wide enough to accommodate both needles.
- 2 reels of thread for the top of the machine.
- Regular bobbin – You will only need the one bobbin.
- Your regular sewing machine. No, you don’t need a fancy machine. As long as your machine can do a straight stitch, and you have a foot with a wide enough opening, you can use a twin needle.
Types of Twin Needle
Twin needles or double needles are available for most makes of machines and have 2 needles attached to the one shank. You normally just get one twin needle in a packet so choose carefully and treat it well.
A twin needle is classified by their:
- Shank thickness
- Purpose
- Distance between the needles
All these add up to a lot of combinations! If your local shop only has a limited choice, prioritize purpose first and secondly shank thickness. As long as the needle distance fits in your presser foot, the distance of the needles is purely personal preference.
Shank Thickness
Common thicknesses include 75/11, 80/12, 90/14 and 100/16. The smaller the numbers, the thinner the needle and the lighter the fabric you will sew with it.
I sew most of my stretch fabric with a medium weight around 80/12.
Read my article on sewing machine needle sizes for more information on what the numbers mean.
Twin Needle Purpose
This is the type of fabric designed to be sewn by the needle and includes jersey, universal, ballpoint and embroidery. For sewing knit fabrics, I recommend the stretch type.
Distance
This is the distance in millimeters between the points of the 2 needles. These include 1.6mm, 2mm, 3mm and 4mm. I prefer the wider distances based purely on aesthetics.
IMPORTANT: When deciding on which distance to choose, double-check that the distance between the 2 points of the needle will fit into your machine foot. You don’t want it to touch the edges and break.
Take a Look at a Twin Needle
See how one needle is ever so slightly shorter than the other? If your needle looks like this it is not faulty!
This is normal and helps create the interlocked stitches on the underside.
How to Thread a Machine with a Twin Needle
Hopefully your manual should give you some instructions on how to thread a twin needle but if it doesn’t, then try these tips below.
Step 1 – Insert the Needle
Put the shank of the twin needle into your machine. The shank at the top inserts into your machine exactly like a regular single needle. It will normally push up into a hole and then be held in place by a screw. Make sure it faces the correct direction with the flat part of the shank facing towards the back.
Step 2 – Replace the Presser Foot
Don’t forget to put your zig-zag foot on your machine as it will have a wider slot in which the needles can fit. Do a double-check that the needles fit in the slot.
Step 3 – Thread the Bobbin
Thread your bobbin as per usual. There is no need to make any changes here.
Step 4 – Thread the First Reel
Take the first reel of thread and thread the sewing machine normally. Pass the thread through the needle on the left.
Step 5 – Thread the Second Reel
Thread the second reel of thread through the machine as normal and into the right side of the twin needle.
Most machines will have somewhere to place this second reel of thread. If yours doesn’t then improvise! You could use the bobbin winder or even a wooden stick taped to the side of your machine. If you are using a twin needle regularly it may be wise to purchase a spool holder that you can place by the side of your machine.
If you don’t have 2 reels of thread in the same color, then just wind a spare bobbin and use that for the second reel.
How to Use a Twin Needle – Ready to Sew
You are now ready to start sewing with a twin needle.
Twin Needle vs Single Needle Sewing
Now, this is a little different from usual. Normally you would sew a hem on the wrong side of the garment. This time you will be sewing on the right side. It feels strange at first but you will get used to it.
Sewing with a Twin Needle
Pin under your hem placing the pins on the right side where you will be sewing.
Place the foot in position ready to sew. Work out what distance to sew from the edge by using your fingers to feel the edge as you sew. Your stitches should be near the edge without going over it.
IMPORTANT: Use the hand-wheel for the first couple of stitches just to double check the needles are not going to hit the side of the foot and snap.
You will generally use a straight stitch to sew hems but you could also consider using a zig-zag or other decorative stitch. I use a straight stitch with a length of 2.0-2.5.
The Finished Double Hem
See how the top has 2 rows of stitching on the underside looks like a zig-zag. This gives your hem built-in elasticity so the stitches won’t break easily when stretched.
TROUBLESHOOTING How to Use a Twin Needle
Occasionally you might find that a crease or tunnel is created between the 2 rows of stitching preventing your hem from sitting flat. This generally occurs in lightweight fabrics where the zig-zag stitches at the back are pulling too tight.
Solve this problem by adding some hemming tape under the hem to give it some body and thickness. This is my favorite method to solve this problem. If you don’t have any hemming tape in your stash, I often substitute double-sided interfacing cut in 3/8 inch (1cm) strips.
Further Reading: Sewing knit fabric hems
If your machine has a pressure adjustment, try increasing the pressure to hold the hem flat as it is being stitched. Adjusting the sewing machine tension may also help.
Alternatives to a Twin Needle
If you can’t get a twin needle then your alternative is to either sew two rows individually or for stretch hems, to use a singular zig-zag stitch. Using a zig-zag stitch helps maintain the stretch of the hem so the stitches won’t pop when pulled.
Further Reading: Sewing Stretch Hems
Twin Needle – In Conclusion
I hope you enjoyed this how to use a twin needle tutorial. Once you have the machine all threaded with your double threads it really is quite easy.
If you have any extra tips for how to use a twin needle please leave your comments below.
Treasurie says
Hi, It seems like the double needle is still not stretching enough. Swim material can have up to 100% stretch or even more. I would try a zig-zag with a stretch needle instead for the hems.
Terrylynn says
I need help. I purchased poly thread 2 spools. I sewed my swim shorts and used all the tricks. 1. Lengthened the stitch 2. Changed tension 3. Very lightly stretched the material 4. Left a really long tail so when finished stretch the material so the bobbin end stretches with the top stitches. 5. No over lapping or back peddling 6. When finished after stretching material took straight needle and the double sew yo the back and knot it off.. And still after swimming for a week my thread is breaking and unraveling. I no longer no what to do. I have already sewn it 3 times. I want it to last. Please help.
Neenah says
Thank you so much for this very informative and helpful article. I have a brother ls14 and wanted the professional looking two stitched row hem but can’t afford a new machine so this is great news.
Inna Meneely says
Thank you very much! Very clear explanation how to use double needles.
Fatima says
Great, thanks for this information
Treasurie says
You can use a double needle to sew the armholes and legs after you have attached the elastic. This gives a really nice professional finish. Hemming tape works where there is no elastic. For example on the sleeve hems of a long sleeve leotard. Sometimes if I don’t have any hemming tape in stock I just cut a narrow strip of double sided interfacing and slip it under the hem. Always use a cotton cloth in between your lycra and iron as many of them melt if you iron directly. Thanks for reading and good luck with your leotard. xx Dixi
Sara Ciccia says
Do you use your double needle to top stitch leotards? Do you find using hem
tape helps with that as well? I tried it once, but didn’t want to mess with the “pucker” issue and just quit…..