Sewing an Overlock Seam

There are dozens of different seams you can use to finish a garment. Sometimes you'll use a French seam on a delicate fabric. Other times, you'll use a flat-fell seam to create strong and sturdy seams on a strong and sturdy fabric. But these seams are both enclosed seams. Useful, yes, but if you need to reduce bulk and create a more flexible seam, you may want to explore the world of overedge seams.




An overedge seam is finished with closed seam allowances and is typically quite narrow. One quick and easy option is the overlock seam. This seam prevents unraveling, making it perfect for knits and other stretch fabrics. To pull this one off, you need a serger, otherwise known as an overlock machine. Once you've sewn your seam, pass the raw edge through the serger. This will both finish the edge of the seam and trim the seam allowance. You can either feed each seam allowance separately and press open, or press them together and finish them as one. If you finish them as one, press the seam allowances to one side.

A serger can also be used to stitch the seam and finish the seam allowance in a single pass. To do this, you'll have to check your serger's manual for specific directions. It's not that difficult, but I still prefer to sew the seam first myself and then finish with the serger. Though doing it all at once may be a little quicker, I find the quality of the seam itself isn't as precise as I'd like.




The benefit of an overlock seam is that it will not fray. It really can't, not bound and trimmed the way it is. But this seam finish doesn't work well on delicate fabrics. Use it for knits and stretch fabrics and you'll be pleased with the results.

Sewing a French Seam

Lightweight fabrics can be difficult to seam, but this difficulty is compounded when the lightweight fabric is also sheer. You don't want the seams to look too much like seams, but you do need seams. If you find yourself in this position, you might want to consider a French seam, which totally encloses the raw edges and gives a neat and polished look. It is a little more work than a standard seam, but the finished product is worth the effort.


Start by stitching a plain seam with wrong sides together. The ideal seam allowance here would be ⅜". This gives you a little space to work with and makes trimming the seam easier. Once your plain seam is complete, trim the seam allowance to ⅛". Press the seam open with a warm iron. Then fold the fabric right sides together, making sure to fold directly along the stitching line. Press well and precisely. This is the key to a good and well sewn French seam.


Stitch ¼" from the fold, totally enclosing the seam allowance you previously trimmed. If you've done your job correctly, you shouldn't seem any of the raw seam allowance on the outside. It should all be enclosed.


On very lightweight fabrics like Swiss batiste, you might want to make the size of the seam even smaller. If you can trim the seam allowance even more and stitch ⅛" from the folded edge if you can manage it. This way you are sure to minimize the appearance of your seams. If you can't pull this off, don't worry. The standard French seam should work well enough.