Sewing 111 - How to sew Open and Closed (French) Seams
Updated: Jan 30
For this lesson, we are going to cover the two most basic seams you will use for sewing, the Open and Closed seams. There are different types of closed seams, but for now we will tackle the most basic one, the French seam. A Seam is a line of stitching that joins two or more pieces of fabric together. We will also go over how to finish your seams for a tidy end to your project.
Seam Allowance – This is the distance between your stitching line or seam, and the edge of the fabric. The width of the seam allowance all depends on what you are sewing and can be as little as 1/8th inch to as wide as 2 inches. The standard seam allowance is 1/2 inch (1 cm).
How to sew an Open Seam (Plain Seam)
This is your basic seam with the edges of the fabric exposed.
1. Thread the sewing machine (See here for details)
2. Set your stitch length to 2.5mm (10spi)
3. Set your stitch width to 0 (if required)
4. Place fabric pieces with Right sides together beneath the presser foot
5. Align the edge of the fabric with one of the seam guidelines e.g. 1/2 inch (1cm). Keep the bulk of your fabric to the left.
6. Put the presser foot down
7. Roll handwheel towards yourself to put the needle into the fabric (or press needle down button)
8. Step on the foot pedal lightly to start sewing slowly. Sew about 2 stitches, then backstitch for about 2 stitches by holding down the reverse button/lever.
9. Continue sewing forward keeping your eye on the edge of the fabric and NOT on the needle. Do not pull or stretch the fabric, let the feed dogs do the work. Simply guide the fabric and try to maintain an even seam allowance.
10. At the end of the seam, backstitch again to lock the seam. Stop sewing. Lift up the presser foot, hold the fabric, roll the handwheel towards yourself to bring up the needle, pull the fabric gently towards the left to remove it.
11. Press Seam open with an Iron to set the stitches.
Closed Seam (French Seam)
It is made by enclosing one seam within another seam. It is good for sheer fabrics and children’s clothes. No need to finish the seam any further.
1. Follow steps 1 to 3 as above
2. You will divide your seam allowance into two parts. If it is 1/2 inch, then half will be 1/4 inch for example.
3. Place fabric pieces with Wrong sides together
4. Align with seam guideline at half your seam allowance measurement (1/4 inch in this example). Sew as normal.
5. Remove fabric from machine and Trim the seam allowance down to about half its width.
6. Fold along stitching line and Press the seam with an Iron, now you have Right sides facing
7. Align the folded edge of fabric with seam guideline at half seam allowance measurement again (1/4 inch). In total you have 1/2 inch seam allowance.
8. Sew straight as normal. Remove fabric and Press
How to finish your seams
It is good to finish your seams to prevent the fabric from fraying and for an overall tidy appearance. A seam can be finished in several ways, but the most basic are using Pinking Shears, Zigzag stitches or Overlocking. Please note that a Closed Seam is already finished, so no other finishing technique is required.
Simply trim the raw edge down with a pair of Pinking Shears. See Sewing 101
Sew a line of zigzag stitches just before the raw edge and then trim the excess down to the line of stitching.
Use a serger or overlocker to clean the raw edges off. 2 or 3 thread overlocking is just fine for this.
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