Sewing with knits 101 - a crash course

Sewers seem to have a love-hate relationship with knits. I will admit when I first started sewing I avoided knits as everyone told me they were hard to sew with and I didn’t think I was ready.


I started sewing when I was 10 years old. My mum was a home sewer and taught me to sew on her old Janome sewing machine. I was immediately hooked and have been sewing ever since both professional and for myself. It was a few years before I attempted to sew with knits and once I did I was surprised at how simple it was to sew with knits. Anyway I got side-tracked, lets get back to some tips on sewing with knits.

 

Knits are amazing to sew with. They are easier to fit than woven and are a lot more forgiving too. There is such a variety in weights, fabric construction, composition and prints that they are really amazing to sew with. We will start out with tips on setting your machine up to best handle knits and then move onto some techniques for sewing. For first time sewers of knits selecting a stable knit such as Ponte, scuba or a heavier cotton lycra would make the transition easier.

 

To start with the settings on your machine are super important in achieving a smooth finish with knits. Most overlockers will have differential feed which is amazing when you are sewing with knits to stop the seams from stretching out as you sew. The needles in your machines are also important and we will touch on both of these below.

 

Needles

Make sure you have selected a jersey or ball point needle that is compatible with your machine. The size should also reflect the weight of the fabric – 75/11 for very light weight, 80/12 for light-mid weight, 90/14 for mid weight and 100/16 for heavy or thick fabrics. Signs that you haven’t selected the right needle include skipped stitches or the stitch not forming correctly. Be mindful that some machines can be fussy if using generic needle brands. Even though you may have the right needle type and size the needle may not be of good quality and thus your machine will not form the stitches correctly. If the fabric ladders or runs when you apply pressure to the seam this is a sign that the needles are blunt or you haven’t got stretch needles in the machine. I generally sew with 90/14 ball point needles in my machine as I mostly use mid weight knits.

 

Differential feed

Ah, differential feed. We love you. Differential feed controls the rate at which the fabric goes under the presser foot, thus controlling whether the fabric is stretched or gathered as you sew. Most overlockers will have differential feed control nowadays. It is a smallish dial located on your machine that has settings from 0.7-2. Some machines the dial is on the right-hand side, others on the front of the machine. Below is a picture showing my differential feed location.

Moving on to the differences in settings of differential feed. A setting of 0.7 will stretch the fabric as you overlock – not what we want when sewing knits (unless you want to do a lettuce hem) but helpful for light weight woven (more on that another time). A setting of 1 is considered a neutral setting. That is the fabric is not being stretch or gathered as you sew. A setting of between 1 and 2 gathers the fabric and is amazing at controlling the stretch in knits.

Below are some pictures of my overlocker with the differential feed set at 0.7, 1 and 2 - I have used extremes below to give you a better idea of how differential feed works. You can see how the seam sewn with differential feed at 0.7 is considerably stretched and wavy, the differential feed at 1 is pretty good but still a little stretched for me, the differential feed of 2 is gathering too much for this fabric. The 'perfect' differential feed for me would be a little more than 1 for this fabric. Each fabric will behave a little different so use scraps to test the setting first is ideal. Something to note with differential feed is that although it is gathering or stretching the seam as you sew it does not affect the amount of stretch in the seam. Testing your settings on a sample to get the right differential feed before starting makes it much easier when you start to sew your garment.


Differential feed - 0.7

Differential feed - 1

Differential feed - 2

My differential feed is located on the right hand side


Threads

When sewing a garment that is using overlocking as the only seam construction it produces a nicer finish if you use matching threads. Since most sewers don’t have 4 threads that will match every garment using a matching thread in the left needle (far left thread) and then any other threads for the remaining 3 threads will produce a similar result. When a seam has pressure placed on it the thread you can see is the left needle which is why this one is the best to match and the others don’t matter so much (see pictures below - blue in left needle, other 3 are white)

 

Sewing machine settings

When using your sewing machine to sew topstitching and hems etc using a walking foot can really help to prevent over stretching the fabric. Selecting a stitch that stretches with your fabric is also important. The most commonly used stretch stitches are zig zag or twin needle however any stitch that has enough stretch for the fabric you are using is fine. Again remember to use the correct needle in your sewing machine also, not just your overlocker. If your machine has the option lowering your presser foot pressure is another way to reduce over stretching. The more pressure that is on the foot the more the fabric stretches as it tries to feed under the foot.

 

Matching seams

To nail the perfect seam join there is a couple of industry tricks I use. One is really simple to do and requires no extra step, the other takes a few extra minutes but it depends on the finish that you like.

Nesting seams – if you prefer to nest you seams when overlocking over a seam join (underarm, crotch etc) then flipping the top seam towards the machine and the underneath seam away from the machine produces a perfectly matched seam. This is due to the fact that the feed dogs will feed the underneath slightly faster than the top layer. By flipping the top layer seam towards the machine it nests the seam into the other seam and makes it easier for the machine to feed both layers at the same speed

Seams the same way – some sewers prefer to have seam allowances pointing in the same direction at joins. By sewing a few holding stitches on your sewing machine over the seam allowances before overlocking stops the seams moving as it feeds under the presser foot. Using a straight stitch is fine here as you are only sewing a few centimetres and then overlocking over the top



 

Hemming

When it comes time to hem your garment using a wider hem prevents over stretching of the hem. Majority of the time I hem with a 2-2.5cm / 3/4-1 inch hem allowance

 

Pressing your garment

Once you have finished your garment using lots of steam when pressing to encourage the fabric to return to shape is important. Areas like hem lines and neck lines will sometimes stretch during sewing so focusing on these areas when pressing produces a beautiful finish.


Happy Sewing!

Michelle Patterns


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