Half square triangles are little workhorse blocks in our quilts. These blocks are great for so many reasons! They can add movement, they can add graphic punch, they can create contrast among your fabrics...all kinds of things! In our new book One Block Remix, we've designed 10 different quilts that are all made from one HST block.
There are tons of ways to make HST's and tons of tools to help construct and finish these blocks. Some methods call for adding 7/8" to the finished size of your units when cutting, which makes my brain and eyes twitch a little. Plus, this method leaves you with almost no wiggle room if you've got a wonky seam, or any inconsistent stitching. I like to have wiggle room! I need wiggle room! So, the method of adding a 7/8", and then cutting doesn't really work too well for me. I'd rather cut the beginning units a little larger and be able to trim them down after sewing. It gives me a little more control over the outcome and makes the cutting easier for me in the beginning because I'm working with whole numbers.
To give yourself that extra wiggle room begin by cutting your squares 1" larger than the size of your finished HST. Part of the extra 1" will be trimmed away, and the other part will be your seam allowance. If your finished HST unit should be 8", start with 9" squares.
After cutting your squares, mark the wrong side of half of your squares by either drawing a light line diagonally from corner to corner, or by folding the square in half diagonally to create a crease. Now, match up your squares to make pairs of 2. One of the squares should be a marked square and will be on the top. Next, layer 2 squares, right sides together, and sew a 1/4" away on each side of the marked line.
Next, you'll cut on the drawn line and you'll have 2 HST's. Carefully press the seam, either towards the darker fabric or open....pressing these seams open does take a little longer but can make things easier for you in the long run when stitching the blocks together. Now for the last step, you just need to trim your HST's. If you have a ruler with a 45 degree line on it, align that line with your seam and trim the unit down a 1/2" from the size of your beginning squares. If you started with 9" squares, trim the HST's down to 8-1/2", which will give you 8" finished HST's. Because I press my seams open, I like to trim a little from all 4 sides. Some people like to trim from just 2 sides. Do what you like best and what works best for you. :-)
I Would love to hear your favorite method for making HST's! How do you mark your squares? Do you draw a line, use tape on your machine, fold your squares? Drop me a line in the comments and let me know. Also, here's a handy little HST step-by-step you can download and keep handy. A HST How-To - Harding Hill Designs
Cheers & Happy Sewing!