All about Seams. Back to basics.

This is a tutorial about working seams and finishing seams. 

A blog post

A seam is much more than joining two pieces of fabric together. A seam can provide subtle shaping to a garment and when correctly made can be almost invisible. Decorative seams add design and interest to a garment.
So what are the rules in sewing a seam?
  • Pin the seam together right sides of the fabric together normally, but there are exceptions which we will come to later
  • Pin the seam edges together matching the ends, notches and any other markings
  • Hand tack the seam. You can omit this if your fabric is easy to handle and if you are experienced at sewing.
  • Stitch the seam with thread which exactly matches your fabric and buy the best quality thread you can afford
  • Finish the seam edge appropriately
  • Trim loose threads
  • Press every seam every time. Pressing gives a crisp edge and makes the thread sink into the fabric making the stitches invisible.
NB Please note that in order to show you the different seam finishes  more clearly I am using a contrast thread. The only time you should sew a seam with a contrast thread is when it is a design feature for example top stitching.

Measuring the seam allowance

Do check your pattern but on a firm fabric the seam allowance is normally 5\8" . If you are stitching a stretch jersey then the seam allowance is usually half an inch.
There are various ways of ensuring that your seam is the correct width. If you do not measure your seam allowance correctly then quite simply your garment will not fit. There are seam allowances measured on your sewing machine throat-plate but many people find these hard to see.

One way to mark the seam allowance is to use a seam guide and measure the seam allowance, there are plenty of different ones available from Jaycotts and you will find a selection, including the one above on this page Seam Gauge
You will also need a marker pen or tailors chalk
Chalk is on this link Chalk products
And marking pens are here Marking pens.

You must always test your fabric before marking it with anything in case it does not come out easily.

Another method is to measure the seam allowance from your needle and place some coloured tape on your machine. Or you can purchase a magnetic seam guide Magnetic seam guide.

Most sewing machines now come with a seam guide which is placed into your normal sewing foot or walking foot. This is my preferred method and I hardly ever remove it.

Now we are ready to sew the seam. Backstitch at the begining and end of the seam to secure the threads and press the seam open.There are rules as to which direction the seam should be sewn in but I do not propose to go into that in too much detail except to say that you should sew similar seams eg bodice, sleeve etc in the same direction.

Seam finishes 

Why is it important to finish a seam? 
  • To give durability and strength to the seam
  • To prevent fraying
  • To ensure that the inside of the garment looks just as good as the outside.

The pinked seam 

In the 1950s and 1960s pinking the edges of the seam was normal. It was quick and easy. In the 1969s especially most young people made their own clothes because there were not that many ready made clothes available for young people, but girls did not want to dress like their mothers any more. So home dressmaking was at its height.
I do not recommend pinking your seams now however, after a couple of washes your seam will start to look very untidy and will start to fray. Save your pinking shears for crafting and for a decorative edge on leather and fabrics like it

The zigzag seam

The next easiest seam is to just zigzag the edge of the seam and then to trim the seam allowance close to the stitching afterwards.

I am sewing with the Brother Innov-is 15 for these samples. It's a delightful machine, reasonably priced and does everything you need a machine to do. It is also lightweight if you need to carry it to classes Brother Innov-is 15 sewing machine

The self bound seam

After pressing the seam open trim one edge to about 1/8"

Fold the longer seam edge over the short edge enclosing it flat.

Stitch close to the folded edge. Don't forget that you will be using matching thread not a contrast as I am doing. This is the wrong side of the garment above

This is the seam from the right side (outside) of your garment. When it is seen with matching thread it will not be noticeable. It is a very robust seam, suitable for fine fabrics, blouses and children's clothes 

The flat felled seam 

Flat felled seam is exactly the same but the fabric is seamed wrong sides together. You will often see it on jeans on one of the leg seams. In this instance a top stitching thread can be used. This does look great on heavier fabrics. Top stitch thread is thicker  than ordinary sewing thread Top stitch thread 

The Channel seam

This looks fantastic on skirts and as a decorative feature on the fronts of  jackets too.

Stitch your seam with the longest stitch you have on your machine and do not fasten off the ends as it will be removed later. Press open.

Pin a strip of the same or a contrast fabric, right side up, to the back of the fabric .
Working from the right side tack along both sides of the seam.
Then stitch between 1/4" and 1/2" from the seam center making sure that both sides are equal. Pull the basting threads out leaving a gap in the centre

This is what the seam looks like from the outside. I love this seam and use it on medium to heavy weight fabrics as a design feature, sometimes with a contrast backing, sometimes not.

The only other step is to trim the underlay to match the seam allowance and zigzag the edges together, making sure to lift the seam allowance away from the main fabric - you are finishing the seam, not stitching it down.

The Hemmed  (Edgestitched) seam

This is a simple and effective way of finishing a seam, simply turn the seam allowances back on themselves and stitch them close to the edge.

The Hong Kong or Bound seam

This is a beautiful finish to any seam. It is used a lot in couture garments because it does look lovely.
You can use a contrast binding as I have done or if your fabric is very fine you could use hand made binding made from tulle or net. It looks fabulous inside an unlined jacket or coat.
Stitch your binding to the seam allowance matching the edges as above.

Trim the seam allowance to 1/4" making sure that you do not cut the binding. Press.
Fold and pin the binding behind the seam allowance. "Stitch in the ditch" making sure that   the binding underneath is stitched down.

Press and admire!

French Seam

The machine I am using now is the Bernina 350PE Bernina 350PE this is a very adaptable, sturdy machine. It has a lot more different functions than my Brother machine. I love both machines for different reasons.

The French seam is another beautiful seam. Use it on lingerie and blouses and on any other fine fabric.
Using a 1/2" seam allowance stitch the seam WRONG sides together.

Trim the seam back so that it is less than 1/4" from the stitching. Press the seam flat.
Then fold the fabric the other way so that the right sides are together and press again.

Pin the seam together and stitch the seam again about 1/4" from the edge , enclosing the raw edges. Press.

What you have on the inside is a very neat seam with no raw edges showing at all

From the front it looks like a normal seam. As with the Hong Kong seam the beauty is on the inside.

Overlocked Seam

A simple way to finish a seam is to use your overlocker. You can also use your overedge foot on your regular machine.
Quick, easy, robust this is a very good choice for everyday garments. You can overlock each side individually or both together as I did
Overlock feet for your regular sewing  machine are available here Overlock foot do ask if your machine is not listed.
My overlocker is the Brother 3034D Brother 3034D overlocker  I do recommend​ Brother overlockers. They are easy to thread and use. Mine adapts quickly to stitch a beautiful narrow rolled hem too.

The Curved Seam

We sew curved seams just about every time we make a garment, the neck facing, armhole facings and princess seams are all curved. How do we deal with them so that they always lie flat?

You are likely to be faced with pattern pieces which look a bit like this. They have to be joined together to make a smooth clean finish on the top edge.

Sew your regular 5/8" regular seam and then trim black to 1/2"

The curve will not turn to the inside unless you release the fabric, so to do that you must make slits at regular intervals right up to , but not cutting through, the seam line. If your fabric is bulky you have to get rid of some of the bulk by cutting V shapes out of the fabric, again at regular intervals up to but not cutting into the stitches.

To press the curve it is best to do it over a tailors ham or sleeve roll. Gradually press the seam open all the way along. You will need to keep repositioning the fabric as it will not be possible to press the whole seam in one go.

Turn the facing to the inside - it should turn in smoothly and neatly if you have snipped into the fabric enough - and then press. Make sure that the seam Is exactly along the top edge for a dress or blouse and slightly to the inside for a tailored garment in a heavier fabric

Open it up again as we are going to "staystitch" the facing to stop it from moving out of place. To do this, on the WRONG side, stitch the seam allowance to the facing.

Turn it the right way out again and press. This is what the inside will look like - of course you're will be invisible almost because you will be using a matching thread.

And this is what the right side will look like. As you can see there is a perfectly smooth edge with no lumps and it looks very neat and tidy. This is the look you are aiming for.

Stretch fabrics 

I hope that you find this post interesting. There are one of two more seams I can think of but I think that these are the most useful. Just a note about stretch fabrics . If you stitch a stretch fabric with an ordinary straight stitch, when you pull the garment even gently, the thread will snap and your garment will fall apart. Therefore you need to use a stitch with some give. I find that a narrow zigzag is perfect for this, followed by an overlocker to tidy the seams. Some people just use an overlocker without stitching the seam first, it is entirely up to you. A lot of sewing machines have various stretch stitches so do try them all out, however if your machine does not have any there is no need to worry because I find a very narrow zigzag just as efficient.

if you want any more information about products then do contact Jaycotts , the details are here, Contact Jaycotts
If you would like any help with your sewing there is a contact form on the right of my blog posts so please do send me a message

Thank you again for reading this