When you learn how to make half square triangles (hst’s) you will find that there are many ways of doing this. I have listed four of them in this half square triangle tutorial, beginning with the most basic method and progressing through three more ways that make more hst’s each time.
The first point to note is that because you are cutting squares to make these half square triangles, you need to begin with larger squares to allow for the additional seam allowance no matter which method you use.
Half square triangle tutorial – method one
The most basic method is to cut two squares in half along one of the diagonals and then sew two triangles from different fabrics back together again using a 1/4″ seam along the long edge. Press the seam allowance towards the darker fabric and trim the corners where the triangle tips stick out.
You will need to begin with 2.7/8″ squares to give you 2.1/2″ half square triangle units. These in turn will give you 2″ finished size squares within the quilt.
Half square triangle – method two
This method is the one that I use most frequently. You can use chain sewing and make lots of them at a time. Again you need to begin with a pair of 2.7/8″ squares. Place them with right sides together and mark a line along the diagonal. Sew a 1/4″ seam either side of the marked line and cut along the line. You will be left with two triangles each with a seam along the bottom. These open up to form two half square triangles which are 2.1/2″ squares.
Apart from speed, this method also has the advantage that you are sewing the diagonal (bias) edge before you cut it, so you reduce the chance of the fabric stretching along the bias.
Half square triangle tutorial – method three
In the third method you can make four half square triangles at a time. Cut two 4.1/4″ squares and place them with right sides together. Sew a 1/4″ seam all round the edge of the square. Cut along both diagonals to create four sections. Each one of these will open up to form a half square triangle which is a 2.1/2″ square.
This is a very simple method and I’m not sure why I don’t use it more often.
Half square triangle tutorial – method four
The fourth method steps the quantity up again – this time you can make eight half square triangles at one go. Cut two 6″ squares and place them with right sides together. Mark a line along both diagonals and sew a 1/4″ seam either side of both of these lines – so that’s four seams that you need to sew.
Cut along each marked line on the two diagonals. In addition, cut the square down the middle both horizontally and vertically.
You will now have cut the squares into eight sections. Each one of these will open up into a half square triangle unit which is 2.1/2″ square.
So there you have it – four methods for making half square triangles. I suspect that I have only scratched the surface here and that there are probably many more methods around, but these ones are all simple to use.
Here’s the video: