There are loads of different ways to finish a seam allowance; in this tutorial I will just cover ten of the methods that you might like to experiment with. Maybe you have a favorite or two in this grouping, and maybe you will be encouraged to try a few other finishes in the near future.
The purpose of a seam finish can be to:
- prevent raveling
- provide a decorative detail on the inside of a garment
- strengthen a seam
- reduce bulk
A felled seam is commonly used on jeans, men’s shirts, and other garments where a flat finish is preferred next to the body and extra strength is needed in the seam itself. Start by stitching the seam with the specified seam allowance, and then trim 1 side of the seam allowance to no more than 1/4 inch. Press the remaining seam allowance over the trimmed seam allowance, turn under, and stitch close to the edge. Well, I guess I stitched sort of close to the edge in my example—could have done a little better there. Sorry!
French seams are often used on sheer or lightweight garments, both to eliminate raveling as well as to provide a narrow seam allowance to minimize show-through. The key point to remember with French seams is you stitch the same seam 2 times—so the sum of both seam allowances needs to equal the total seam allowance for the garment. For example, for a 5/8 inch seam allowance, place the wrong sides of the fabric together and stitch a 1/4″ seam. Trim, press, then fold along the first stitching line so the right sides are together. Stitch the second seam 3/8 of an inch from the pressed fold. Perfect! A totally enclosed seam that equals 5/8 of an inch!
Often used in couture sewing to “lightly” finish the seam allowances even on a lined garment, overcast stitch by hand along all seam allowances. It is a surprising fun and relaxing way to sew!
Hong Kong finish
A Hong Kong finish is most often used in an unlined coat or jacket to both prevent raveling and provide a decorative finishing element. Start with bias strips of fabric (lining fabric is a good choice with wool) about 1–1/1/4 inches wide, and with right sides together stitch a strip to each side of the seam allowance using a 1/4 inch seam. Press the bias strip away toward the raw edge, and fold it around to the back side of the seam allowance. Stitch in the ditch from the top side to secure the back of the bias strip. Trim any extra fabric on the back side.
Overlock with serger
Overlocking with a serger is a fast and easy way to finish seam allowances. You can serge either each seam allowance individually and press the seam open and flat, or you can serge the two seam allowances together. You can use either a 3-thread or 4-thread overlock stitch for this finish.
Overcast with sewing machine
Most sewing machines include an overcast stitch, which is similar in function to the overlock stitch on your serger.
Pinking produces a very flat seam finish, and gives a vintage look to the inside of your garments. Pinking requires a wavy blade for your rotary cutter or special pinking shears.
A line of straight stitching close to the edge of the seam allowance can be used alone or in combination with a pinked edge to reduce raveling.
Turn and stitch
Turn each seam allowance to the underside 1/4 of an inch, and stitch with a straight stitch close to the edge.
Similar to the overcast stitch, a zig-zag stitch can also be applied close to the raw edge to reduce raveling.
Select the seam allowance you want to use based on your fabric, how the garment will be laundered, and the look you want for the final garment. It is a great idea to sample several seam finishes on leftover fabric to see what will work best.
Do you have a favorite seam finish you like to use? How many of these 10 finishes have you tried in your garments?