Have you ever heard the phrase that it doesn’t matter how you start, but how you finish? Well that’s mostly true in sewing as well. The way you finish your seams is one of the most important steps in sewing a garment. The right seam finish can really make your garment look like it was professionally made.
One of the main reasons to finish your seams is because of the fact that the fabric will fray over time. You could potentially have your fabric fray past your seam stitches which will cause your project to fall apart! Some fabrics fray more than others. If you just look at a silk dupioni it’ll fall apart, whereas a canvas duck holds up to whatever you throw at it. And if you’re sewing with knit fabrics you don’t really need to finish your seams since knits don’t unravel. (You can learn more about different kinds of knit fabrics here). Finishing seams is more than just for proper function - it's also for the beauty of it!
When we talk about “finishing” your seams it simply means to cover the raw edges of your seam allowance to prevent them from unraveling or to give them a nice and neat look. There are a number of ways to do this.
One of the fastest ways to finish your seams is with pinking shears. Pinking shears look just like scissors except that the blades have a zig-zag shape to them. Fabric is less likely to fray if it’s cut on a diagonal. That’s because of the way that fabric is woven. If you use this method you’ll sew your seam, trim the edges with your pinking shears, then press them open like this. When I first started sewing this how I finished all my seams and many years later those garments are still holding strong.
What you see from manufactured clothing is most likely an overlocked/serged seam. This encases your seam with stitches making it less likely that it will fray and it gives your garments a more professional look. This is done on a machine called an overlocker or a serger. If you don’t have a serger, you can learn how to overcast stitch without one. Serging your seams is also very quick and very easy but it does require and overlock machine. If you don’t have one you can always use another method but they are kind of life changing when you do finally get one.
If you don’t have an overlocker and want to achieve a similar look, you can do a zig-zag stitch on your sewing machine to finish your seams! This is also super simple and can be done on any machine with your standard equipment. Just simply set your machine to a zig-zag stitch and then stitch up close to the edge of your seam allowance.
I especially love French seams for finishing my seams. French seams are usually used on more delicate fabric and it completely encases the raw edge of your seam allowance. A French seam usually marks a high end or more expensive piece of clothing. So if you’re sewing a silk blouse, you’ll want to use this type of seam. Don’t use a French seam on a heavy fabric like a canvas though because it just doesn’t work well.
French seams are traditionally done on woven fabric but can also be used on light weight knits if you want that beautiful finish that a French seam gives you. Get the full step by step on how to make a French seam with knit fabric.
Start by sewing your two pieces of fabric with wrong sides together with a 1/4″ seam allowance. Then flip it and give it a good press, pressing your seam allowance to one side. You can trim or grade this seam to remove some of the bulk. You will then sew a 3/8″ seam with the right side facing. And voila, a gorgeous French seam.
Flat felled seam
A flat felled seam is great for clothing that will have a lot of strain put on the seams. It is a very sturdy way to finish your seams. It’s very strong and also encloses the raw edge of the seam allowance like a French seam does. You’ll typically find a flat felled seam on the side seams of your jeans. Flat felled seams are super easy and just as fun to make as French seams. Go here to watch a video on how to make a flat felled seam.
Trimming or grading the seam
You may also want to grade your seams which means to trim your seam allowance at different widths for each side. Below you can see that one side of my seam is slightly wider than the other. This is grading. Any enclosed seam that will be laying flat against your body should be graded. Think shoulder seams, necklines, cuffs, or princess seams. Grading your seam takes the bulk out of it helping it to lay flat and be less visible from the right side. When trimming your seam like this keep in mind that the wider side will be the side facing up. closest to the outside. The narrower side sits against your body. If you’re grading a curve then clip your curve after you grade it.
If you can believe it there are many more seam finishes. I just included ones that you’ll likely use. These seams will really carry you very far in your sewing journey.
One last thing that’ll make all of your seams top notch is to press them. After every time you sew a seam it’s best to press them! Not finishing or pressing your seams can make your garment look very sloppy. Taking the care and extra time to make the inside of your garment look just as good as the outside is a mark of a well made piece of clothing.
-- Originally written by Jessamin Jensen. Archived by Holly Hetzner.