The half square triangle (HST) is a very common component of patchwork quilts. These blocks consist of two right triangles. Because of the stretchy nature of fabric cut on the bias, it may be preferable to make your half squares in the following way, rather than cutting out triangles and sewing them together. This is an easy step by step guide to making one. Note: When making this block it is a good idea to make them slightly oversized and then cut them down to their unfinished dimensions.
Yield: 1 block
cotton quilting fabric in two or more colors
1 paper or plastic template, size of your block before stitching seams or with allowances added
self healing cutting mat, optional
rotary cutter, optional
Using your template, cut two (or more) squares from your fabric.
Using your ruler, on the wrong side of one of the squares, draw a line from one corner to the opposite corner. You have just defined the triangles.
Again using your ruler mark two sewing lines, one on each side of the dividing line, 1/4 inch wide.
Place the marked square on top of your second square, right sides together.
Line up the edges of the squares and pin together.
Sew along the two seam lines to the right and left of the original dividing line. Tie the threads and cut off extra thread.
Using your scissors or a rotary cutter cut the two layered square in half along the original dividing line.
Open your square and fold the seam towards the darker color of your block.
The final step is to press the seam. You may finger press, use a seam pressing tool, or an iron. Do this step carefully so as not to stretch the seam.