The simple half square triangle. What a wonderful thing! You can make hundreds of different quilts using just a HST. Comprised of a square made from two equal right triangles, this block is one of the most used and most versatile quilt blocks in history. If we're going to be making them (which we are) let's make them right. I've actually got 3 tools to make a half square triangle perfect.
As a quilt pattern designer, I find myself continually drawn to half square triangles. It is a foundational shape to some of the most famous, traditional quilts hanging in museums as well as simple, modern baby quilts found on Etsy. With multiple techniques used to sew this block, it is easy enough for beginners, but can be turned, rotated, resized, recolored, and laid out in infinite ways, so that even the most advanced quilters will be stimulated.
With so many patterns and designs hinging on this block, it’s important for a quilter to know a few handy tricks and have the right tools available. HSTs aren’t going anywhere, so let’s do ‘em right. Crisp edges and perfect seams, here we come!
Before jumping in, if you're interested in making the Rocksteady quilt seen here, you can find it in the shop!
3 Tools to Make the Perfect Half Square Triangle
With Thanksgiving behind us and Christmas steamrolling ahead, most of my friends are on some kind of high-protein, no-carb crash diet. I can’t say the word “starch” without having them slowly back away. My fabric, however, never looked better when paired with a bottle of starch. After sewing half square triangles, I spritz a little bit of it (Best Press being my weapon of choice) on each block right before pressing.
You’ve never seen such a flat and cooperative half square triangle as you have after I’m finished with it. Using starch on each block can take extra time and (to be honest) get a little bit tedious. However, if you choose to spray starch on some of your blocks, I highly recommend spraying all of your blocks. By doing so, each half square triangle will have the same feel and will feed into your sewing machine in the same way. Voilà — no pulling, snagging, or tension issues due to fabric.
And have you ever had your sewing machine eat a quilt block corner? That problem will be minimized by stiffer, starchier blocks.
For some reason I own 3 of these. Two of them are even the same size. I guess that means I really like this tool! When it comes to cutting, I can be a little bit dangerous. Suzy Danger Quilts Williams is what people call me. When I’m alone and left to my own devices, I sometimes (brace yourself) use my rotary cutter in all different directions — even towards myself if it helps me cut faster. (Cue *gasp*)
I used to do this when trimming my HSTs until a worried friend bought me a rotating cutting mat. I rolled my eyes, accepted the (unwanted) gift, and then proceeded to fall in love with it! Rather than torquing my back into weird positions or cutting toward myself so I didn’t have to move my ruler, this rotating mat allowed me to keep the block and ruler stationary while rotating it’s position so I could always cut away from myself. My fingers are now much safer and my friend is a lot less worried.
Like I said before, I’m all about safety. It’s actually my middle name too! Suzy Danger Safety Quilts Williams.
There are some ultimate truths in the quilt world. One, for example is, “You can never have too much pretty fabric.” Another, lesser known truth is, “You will never regret a square ruler purchase.” If my half square triangles are supposed to be 4 ½" trimmed, I will make sure that I have a 4 ½" square ruler. In a lot of my quilt patterns I even add that a specific square ruler is highly recommended. (eg. the Kris Kross quilt is made much easier by a 6 ½" square ruler.)
Not only does the right size of ruler help you cut faster, it also helps you cut much more accurately. When purchasing a square ruler, make sure that there are 45° guidelines printed on it. That way, when trimming, line up that 45° line with the seam of your half square triangle. Now your block is not just square, but also each of those right triangles are perfectly equal. Ta-da! The most perfectest half square triangle in the WORLD!
Pair a square ruler with a rotating cutting mat and you will become a machine of efficiency. Possibly too efficient. Maybe it’s time you take a break or treat yourself to some more of that pretty fabric.
Just remember that if you want to join with the other HST STARS you need:
- A Rotating cutting mat and a
- Square ruler
Too cheesy? Sometimes I can’t help it. My middle name is Cheesy. Suzy Danger Safety Cheesy Quilts Williams. Full legal name.
Do you have any half square triangle trimming tips? Let us know in the comments!