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.
Check out this half square triangle tutorial to learn 3 different techniques to make the simple HST.
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.
Click here to read more about different kinds of starch and even how to make your own!
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!
30 thoughts on “3 Tools to Make the Perfect Half Square Triangle”
All good tips! I’m about to do a Nordic Triangles quilt so this post was perfectly timed! 😊
oh good! And another tip is to size up your HSTs so you can trim down – that’s for the more precise quilters in the bunch 😉
If you trim your HSTs, a Bloc Loc HST ruler is a must-have. Quite a few stores carry the 6.5″ size, but there are other sizes on blocloc.com.
I use a tucker trimmer which makes squaring up so easy!
I just participated in a 2 color quilt challenge and used Suzy’s Triangle Jitters pattern. The starch makes all the difference in the world because all four edges of each block are on the bias. Love Suzy triangles safety etc Williams!
My most favorite (and cost effective) HST tool is the Deb Tucker – Tucker Trimmer. One ruler, many sizes of HSTs, perfectly sized and trimmed. BlocLocs and square rulers are great but I need to *minimize* all the crap I carry around or have around and having one tool for many purposes is the answer. She also has one for Flying Geese that is a MIRACLE!!
I’ll have to check that out!
This quilt is beautiful is the pattern available?
Thank you! It’s the Rocksteady quilt pattern.
Thank you for the advice. I may have to try the Best Press. We almost have the same middle, except “safety”. 🙂
I have a collection of square rulers, rotating mat, and I starch before I cut. Would you suggest starching again before pressing the HSTs? This was a really good post!
If you already starched before you cut, you don’t need to add more into the fabric. However, if you want really flat seams, use a bit of steam and a Tailor’s Clapper.
I purchased a Tailor’s Clapper last year and while it takes a little longer to press it makes my blocks SOOOOO dang flat that I just smile every time.
I see a lot of people mention bloc loc. What are your thoughts on them?
To tell you the truth, I haven’t used them and don’t know a lot about them. I believe what makes them special is they all have a seam in the plastic on a 45-degree angle so they can “snap” into the HST seam, making trimming accurately easy. Definitely something I’d like to try out!
I agree on the block loc rulers. LOVE THEM!
Oh Suzy – I am joining this party late but have you never tried the Sue Daly Quilt in a Day Triangle Square Up Ruler?? You trim your hst BEFORE you press them open. Holy Moly it makes squaring them up so.dang.easy! Thanks for always making me chuckle while imparting so much quilty wisdom!
That’s new to me, but I’m Googling now…Thanks for the tip!
Waaaayyyy late to the game here, but just want to tell you know how much I enjoy the newsletters (as well as the gazillion quilt patterns I own!!). Love the helpful info, adore the humor. FFL (fan for life!)
You’re so sweet! Thank you, Jean!!
great comments about sq. up rulers!!
Hi Suzy! Do you have a tutorial for making HSTs 8 at a time method? Thanks! Love your blog!
I do! Check out this post – https://suzyquilts.com/half-square-triangles-tutorial/
Helpful tips! Starching definitely helps. HST’s are my favourite. I use Creative Grids 4-in-1 triangle ruler. It saves me a lot of time trimming HSTs.
I’d really love to see more about the fabrics you show in these wonderful posts!
I’m so glad you like this fabric! The tricky thing about posting fabric info is after a year or so, fabric can get really hard to find. A lot of fabric only gets a single run of printing. The printed fabric used in this tutorial was designed by Kelly Ventura for Windham Fabrics. Kelly is no longer designing quilting fabric for Windham, but you may be able to find it still if you search online shops.
My issue is not making the triangles, it’s getting the points to line up! Any hints?
The points to line up when you’re sewing them all together? One thing that would help is pressing all of your seams toward the darker fabric so that when it comes time to sewing the HSTs together, you can nest seams. This post on using fork pins shows what I’m talking about – https://suzyquilts.com/fork-pins-the-best-way-to-match-seams-perfectly/
I recently found your blog while searching hand quilting. And at first I gotta admit I was like what is this pretty lady gonna bore me with? But then when you started talking I started laughing at some of the things you would say. And all the info you gave was super helpful. So I subscribed. Now I’m reading this and your corny (dangerous safety cheesy) jokes are cracking me up. So thank you. You aren’t just a boring pretty lady but a funny one too!