Inspired but don't know how to make a half square triangle? Below is a mini-tutorial showing how to make both half square and quarter square triangles.
To make the block shown in the final photo…
You will need
2 squares in colour A measuring 4 1/4 x 4 1/4"
2 squares in colour B measuring 4 1/4 x 4 1/4"
4 squares in colour A measuring 3 1/2 x 3 1/2"
1 square in colour B measuring 3 1/2"
Tip: You can make the finished block as small or as large as you like, just remember to add 3/4" to the squares used for the quarter square triangles, to allow for seams.
Take the 4 larger squares and on the reverse of the lighter 2, draw a diagonal line from one corner to the other (this will eventually be your cutting line). Then draw a second parallel line 1/4" either side of the first line (these will be your sewing lines). In the photo, I have marked the cutting line in red, and, the sewing lines in blue. With right sides together, marry the A and B squares together. Pin and sew along the blue lines.
Then, making sure you have sewn along the correct lines (there will be much cursing if you haven't) cut along the cutting line. You should now be left with 4 triangles, which when pressed open will give you your half square triangles. (Rather annoyingly, I didn't take a picture of one showing the right side, but you can see one peeking out from behind the reverse of a half square triangle in the picture below).
So, to make quarter square triangles, you pretty much repeat this process all over again. Draw a cutting line diagonally from one corner to another, and a parallel sewing line 1/4" either side of this line. With right sides together, place one half square triangle on top of another, making sure the triangles of your original squares are opposite each other and not on top of each other (you will be deeply frustrated if you get this bit wrong, so it is worth double-checking before you sew and cut). Finally sew, cut, press and there you have your quarter square triangles, which for some pleasant reason, always remind me of fluttering butterflies!
To finish the block, take 2 of the quarter square triangles and place them either side of the 3 1/2" square in colour B (the centre square). Allowing for a 1/4" seam, sew first one, then the other quarter square triangle to either side of the central square. Open and press flat to get your central horizontal strip of the block. Now, take another quarter square triangle and sew a 3 1/2" square to either side of it to make the top strip. Do this again with the remaining 2 squares and quarter square triangle to make the bottom strip. Throughout, pay careful attention to the orientation of the quarter square triangles as you want them to face the same direction, whichever way you turn the block.
Tip: when sewing the strips together, marry up the seams and sew from one seam outwards, then the next seam outwards, then from seam to seam. It takes longer than sewing one straight line but it does achieve a more accurate result.
I hope you find this useful, and not confusing, because it really isn't a difficult technique. I'd also love to hear from you if you've seen some particularly inspirational uses of this technique.
PS: I've added a new page to this blog that lists some of my favourite places from which to buy fabric, yarns and haberdashery, both locally and online.