-Sandwich two pieces of fabric together with right sides together.
-You're going to mark the fabric with diagonal lines. Line up the ruler at a 45 degree angle on the edge of the fabric, and draw a line from the corner of the fabric, all the way down the edge of the ruler. A gel pen is recommended.
-You'll continue to line up the ruler on the lines you draw...all depending on the finished measurement of the triangles you're trying to make. For example: If you're making 1" finished triangles, then space the lines 1.5 inches apart on the ruler. If you're making 1.5" triangles, the line spacing will be 1 7/8" apart on the ruler. The triangle template contains the measurements to measure for each size triangle.
Step 2: SEW
-Sew a 1/4" inch seam on each side of the drawn diagonal lines. You'll have your hand-drawn lines, and sewn lines on each side of them. It's ok if you're stitching line is not exactly 1/4". Don't stress about accuracy on this--just do the best you can. That's part of the beauty of the design of the template!
Step 3: CUT
-Cut the strips apart on the lines you drew earlier.
-Take one cut strip. Put the triangle template on it, with the long side butted up against the seam line you sewed.
-When it's lined up, and you're holding down the triangle, take your rotary cutter and cut against the short side of the template. The cuts on the short side of the template are what make this extra accurate, so you must be accurate on this part!
-after you make a cut, flip EITHER the template upside down OR flip the fabric over to the other side. EITHER/OR...not both. In these photographs, I flipped the template. The long side of the template will again be butted up against the opposite seam, and the short side of the triangle should be aligned perfectly with the cut side you just made. Cut another short side.
-continue flipping EITHER the template OR the strip until you're done cutting the triangles. That's it!
-Carefully press the "perfect" half-square triangles open.
**The sample pictures is an UNFINISHED 2 1/2" half-square triangle.