Some quilt block patterns, such as Woven Ribbons (left), require the use of the partial seam technique to complete the sewing of the design. These designs typically (but by no means always) have a center square surrounded by four identically shaped pieces in a sort of whirling effect.
If you’d like to practice this technique before using it in a project, cut one 3-1/2” center square, four 3-1/2” x 6-1/2” rectangles, and follow the steps below to make a sample block.
Step 1: Place the first rectangle next to the center square exactly as shown in figure 1. Sew only the first part of the seam as indicated by the red line, stopping and backstitching midway along the seam line on the center square.
Step 2: Place the second rectangle as shown in figure 2, to the left of the first rectangle and the center square. Sew the seam and press toward the center square. Add the third rectangle in the same way, and then add the fourth rectangle, pressing the seam each time toward the center square.
Step 3: Now fold over the nearly completed block along the very first, partially sewn seam. Line up the raw edges and finish sewing the seam as shown by the dotted red line in figure 3. Press block and you’re done!
I often use this exact method for my quilt borders, since it’s easier and uses less fabric than mitered borders, and more interesting than standard butted borders (two strips sewn to sides, then to top and bottom).
Although the practice block uses rectangles around a center square, it is possible to have pieces of other shapes if the center square is rotated or off-center. For example, Woven Ribbons has triangles surrounding the center square. But the technique is the same no matter what the surrounding shapes are. In fact, the center piece doesn’t even need to be a square! Pentagram (right, available in my Etsy shop) has various irregular shapes surrounding a central pentagon.