One of my favorite types of quilts to sew is one made with lots of half-square triangles.
I think I like to sew half-square triangles because they pack a big punch in a quilt….and are easy to sew.
(If you know a few tricks!)
You know I’ll share them with you!
How to sew half-square triangles
If you’re following a pattern that calls for half-square triangles, you can check to see if the pattern follows this method below. If so…go for it. No measuring needed. Just read on to find out how to make your squares perfect (because most patterns don’t give you in-depth tutorials, I know!)
First, find out the finished size of your half-square triangle “unit.” By finished size, I mean the size the block will be when sewn onto its neighbors.
Then cut two squares 1in larger than the finished unit will be.
If the finished half-square triangle unit is supposed to be 3in, cut two squares that are 4in square. If the unit is supposed to be 6in, then cut two squares that are 7in square.
Below, I’m making 3in half-square triangle units. So I’ve cut two pieces of fabric that are 4in square.
Next, layer these on top of each other, right sides together (photo 2 below).
Now, draw a line on the diagonal, connecting two corners.
Take the squares to your machine and sew 1/4in away from the drawn line, on both sides (photo 4 below). (Check out this post to learn some tips for sewing a perfect quarter-inch seam!)
Now, use your rotary cutter, ruler and mat to cut the pieces apart on the drawn line. If you’re new to rotary cutting, learn more about how to use your rotary cutter and mat before you get started!
Open your half-square triangle units, and press your seam allowance to one side as shown in photo 2 below. Usually you’ll press toward the darker color, but your quilt pattern should give you pressing instructions.
Now, lay your half-square triangle unit on your mat, and trim it so it’s 1/2in larger than your finished unit. For instance, if your finished unit is supposed to be 3in (as mine is in this example), trim your block to 3 1/2in square. You’ll cut off the little “ears” during this process.
As seen in photo 4 below, usually this means you’ll only be trimming your block about 1/8in on each side.
When you’re finished trimming, you should have two completely perfect half-square triangle units!
And to make your quilt-top sewing go even quicker, check out these tips for chain piecing.
Deanna McCool writes for sewmccool.com. To make sure you don’t miss a tutorial, please follow SewMcCool by e-mail (the link is at the top of the right-hand column) or join me on BlogLovin’ – the button is just below the e-mail feed box! 🙂