Measuring Note: One finished HST will measure approximately 1/4" x 1/4" smaller than the square you began with. For example, if you start with 3" squares, one HST will be approximately 2.75" square. I recommend starting with squares approximately 1/2" larger than you need you unfinished HSTs to be, and then trimming the HSTs to the desired size. Because it's so much easier to trim down than to rip out and try again if you seam allowance is off!)
There are several different ways to make HSTs, but this is my favorite method - - - two for the price of one!
And away we go...
To make one half square triangle, cut two squares the same size from contrasting/coordinating fabrics.
On the wrong side of one square, draw a diagonal pencil line from corner to corner.
Place the two squares right sides together with the pencil line facing up. Using the edge of a 1/4" presser foot as a guide, stitch the squares together by sewing 1/4" on either side of the drawn line.
Cut along the drawn line.
Press each side open and there you have it - - - two half square triangles!