Hello Quilters! Triangles are a challenge for beginner quilters, but at some point you’ll run out of squares-only designs. So let’s take a look at the most common triangle used in quilting, the 45o triangle. It is one half of a square and called a ‘half-square’ or ‘short side’ triangle.
Cutting a square in half diagonally will create this triangle. The short sides of the triangle will be on the straight grain of the fabric and the long side will be the bias. The measurement of the short side is used when referring to the size of the triangle.
There are many different methods for making the half-square triangle unit. In the “Indigo Square” quilt, we start with squares. This keeps the bias edge stable while sewing. Pencil mark from corner to corner, then sew a 1/4″ away from the marked line on both sides. Cut on your pencil mark.
There are marking rulers that let you mark the sewing line. I’ve never been a gadget girl, but I now have several of these.
Now, press the seam allowance to the darker side. Don’t stretch, just press open. The little triangle tips are called ‘dog ears’. Lately I’ve heard them called ‘bunny ears’ – cute, right?
Trimming (or Squaring up): After sewing a half-square unit, many times it will need to be trimmed slightly to the stated size. It is best to trim a little from all four sides. Using a square ruler, place a half-square unit underneath one corner of the ruler, lining up the 45o line on the ruler with the diagonal seam. Be sure the unit is placed within the measurement needed for the unit and slightly trim the two outer edges.
Raise the ruler and turn the unit so the two trimmed sides are closest to you. Match the diagonals and trim the remaining sides to the finished size, if need.
Now isn’t that a lovely half square triangle? It takes some time to mark and square up each one, but the advantage is a perfect square every time. Let’s practice a few more!