When Two Seams to be Joined Are Uneven in Length…….

When sewing garments that require joining two seams that are uneven in length, there are three different seam techniques that you could consider.  Keep in mind the “difference” between the two seam lengths will be determined by where the seaming is being used – if it’s for fullness along a yoke line, or decorative stitching along a shoulder seam, etc.  The pattern that you are using will have the correct seam lengths, and the following diagrams show the difference between “easing” and “gathering”.



When two seams to be joined are uneven in length, the longer edge must be drawn in to fit the shorter side.  This is done by easing or gathering, as shown above.

Slight ease is the type of fullness that would be needed along the back side of a shoulder seam.  The use of pin basting for this type of easing is sufficient.  The pins will hold the fabric layers together to keep the fullness from slipping during the stitching process. 

Moderate ease as used in yoke areas can be controlled by a dual process of machine basting, then pinning.  Machine baste just the area of the longer piece that is to be eased in, then pin the seam at the ends of the basting and notches as shown in the middle diagram.  Pin as needed, then stitch the seam carefully, removing the pins as you stitch.

Gathering is the process of drawing fullness into a much smaller area by means of two rows of machine basting, like you would see in a gathered skirt.  Using this method you would stitch two lines of basting threads along the longer piece of fabric that would require the gathering.  Leave a long length of thread at each end, so you can gather each end toward the middle.  Be sure to pin the seam edges together at the matching points or notches.  Pull the gathering threads, then pin the fullness in place as you did for the moderate ease.  Stitch the seam with the gathered side up in order to prevent the gathers from becoming crooked and getting too much fabric sewn in with the gathered area.

The above information is an excerpt from the book Basic Clothing Construction.