The most common of seam stitches is the straight stitch seam. However, there are many versions of this seam and many seams that are better suited to different fabrics. Below are examples of different kinds of seam stitches and seam finishing that is best suited for the fabrics you may be using.
Using your straight stitch presser foot , sew a straight line, 5/8" in from the edge. Press open with a steam iron. You can really only get away with not finishing a seam edge if your fabric does not ravel easily. I recommend finishing your seam with any of the following finishing techniques.
Straight stitched seam with pinked edge.
Pinking shears are a quick easy way to prevent fabric from raveling if your fabric is not easy to ravel. The photo on the right shows a safety stitch between the seam and the pinked edge. This gives a little more security for the seam.
Straight Stitch with a serged finish.
If you have a serger , you can use it to serge the edges of a straight stitch seam, then steam iron the seam open.This is a good way to prevent bulk in some garments and projects. You can also press to one side if you prefer.
As well, you can use this seam when you want to leave room for growth in a garment. An example would be in the side seam of a skirt for a child.
Flat Felled Seam Stitches
A good seam, used for denim fabric and other woven fabrics to give extra strength to stress areas like the inner thigh of jeans. Flat felled seams are also used for decorative interest.
Sew your straight stitch seam.
Trim off 3/8" of one side of the seam.
Press with a steam iron toward the smaller seam allowance.
Press over the wider 5/8" seam allowance to cover the now, 2/8" seam allowance.
Stitch a straight seam allowance parallel to the original seam.
The French seam is best suited for sheer fabrics. Your seam stitches will not show and it is clean and professional.
Sew a straight seam with wrong sides of fabric together and right side of fabric showing, 2/8" from the fabric edge.
Turn your fabric to show the wrong side of the fabric and press flat.
Sew a second straight stitch seam 3/8" from the fabric edge and press flat.
Turn the fabric back over to the right side and press.
You now have a neat and tidy seam.
There are a few different types of stretch stitches you can do on a regular sewing machine , depending on the type of machine you have.
A triple stitch is good for sewing knits and I would use this stitch in stress areas such as in the crotch area or under the arm, if you do not have a
I do not use this stitch for sewing full seams, only because it takes a while for my sewing machine to complete a seam. As the name says, it literally stitches three times, before it moves to the next stitch. So this stitch is time consuming.
Another alternative to a serged seam is the stretch stitch. (this is what my machine calls this stitch.) Again, you would use this for any of the stretch fabrics..
This fabric is a spandex knit. I used a stretch stitch here and notice that you will have to trim your own seam allowance, unlike the serger that has a built in knife that trims and sews the seam stitches all in one. In any case the stretch stitch is a good alternative for stretch knit fabrics.
Machine or hand basted stitches are used to secure a temporary seam. Machine basting is commonly 3.0mm in length or more. Whether you hand baste or machine baste, you will remove this stitch at a later time.
The photo is an example of a machine basted stitch used in the zipper construction of a centered zipper.