In the quilting world strip piecing is where you sew strips of fabric together to create a strata. It can be from two to a number of strips. Then you crosscut the pieced strip into sections of units needed. The picture below shows how I cut a pieced strip. Square up the edge. Set the acrylic ruler at the size you need to cut. In my picture it's 2-1/2". Line up the seams of the pieced strip with horizontal lines on the ruler. Don't use the edges of the strip pieced to line up the ruler. At times the edges are not straight due to pressing, stretching, as you can see in my picture. Using the seam lines as a guide keeps it squared. When the units are sewn to a block or another unit the edges seem to square up just fine. Give it a try. It works.
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