How to: Make Half-Square Triangles (HSTs) using the 32-at-a-time method

Half-Square Triangles (HSTs) are a versatile and common quilt block. Each time l make and use HSTs, l'm always reminded of a chameleon, because of the many varied ways you can use them to create different unique designs. In this tutorial, l’m going to show you how to make Half-Square Triangles using the 32-at-a-time method; useful for those designs that require you to make lots of HSTs. You can read the making Half-square Triangles (HSTs) using the 4-at-a-time method here.

This post contains affiliate links

This post contains affiliate links. I may receive a commission through purchases made through links from this post.

Making HSTs using the 32-at-a-time method came in handy and was perfect for a quilted table runner project l was working on using the Love Box quilt pattern. I used Michael Miller fabrics; Basics range (Fairy Frost for the hearts and Cotton Couture for the background). More photos of this project at the end of the tutorial.

 

HSTs tools and notions 

Before you begin, you’ll need to gather your sewing supplies on top of your fabric and sewing machine. You certainly don’t need specialty rulers, but they are helpful in making the process easier. 

Quilting rulers (including an HST slotted trimmer)
Sewing thread
Iron and ironing board (l love my wool pressing mat)
Fabric pen or pencil (I use a Hera Marker to draw my lines)
Rotary cutter
Seam ripper
Cutting mat

Before you begin

RST means right sides of the fabric together.

Unfinished size means the size of a Half-Square Triangle before it's sewn into a quilt, inclusive of the ½" seam allowance (¼" on each side).

Finished size means the size of the Half-Square Triangle after it's sewn into a quilt minus the ½" seam allowance.

For example, a 3 ½" unfinished HST will become 3" finished.

Quilt maths

In this tutorial, l’m going to show you how to make 3 ½" unfinished HSTs. You’ll need two pieces of fabric that are 16" square. Let’s take a moment to work out the quilt maths for a 16" starting square measurement, before we move along. 

Take the size of the unfinished HST and multiply that by 2 plus 1". Take this number and double it to give you the size of the beginning square. 

Using the 3 ½" unfinished HST example, this is what the calculations will look like; (3 ½" x 2 = 7, 7 + 1 = 8, 8 x 2 = 16 the size of the starting square to make (32) 3 ½" HSTs)

I’ve done some Quilty maths for you with different unfinished sizes for your future reference.

Click here to receive your single page HST calculations and tutorial!

OR

You can purchase the printable post here!

Now back to making our HSTs

1. Pair two 16" square pieces, RST. 
2. On the wrong side of one of the fabric pieces, draw the following lines;

• draw a vertical and horizontal line to make 4 quadrants.
• draw diagonal lines on both diagonals of the 16" square to form a big X.
• draw diagonal lines to form a small x in each quadrant. 

3. Pin as desired to hold the pieces together.
4. Sew a ¼" seam on both sides of the marked diagonal lines (the bold lines).

Word of caution: do not, l repeat DO NOT sew along the vertical or horizontal lines otherwise you'll be enjoying a play date with your seam ripper. 

 

5. Using a rotary cutter, cut along the the drawn lines as well as the horizontal and vertical lines including the ones in the four quadrants. 

Remember that word of caution? This is what happens when you sew along the vertical and horizontal lines. You'll end up with two sides that are sewn together, creating a pocket.

And just like that, you've made 32 HSTs in one go.

Now, this next step is where the nifty HST slotted trimmer comes in. 

6. Trim HSTs to 3 ½" square before pressing and opening up your blocks. You can see a video of it in action here.
7. Press seams open.

OR

If you're not using the HST slotted trimmer.

8. Press seams open.
9. Trim HSTs to 3 ½".

 

Some finished (well, not quite finished) photos of my table runner using the 32 at-a-time method for my Half-Square Triangles. I'm debating whether to put a faced binding or just go normal binding for this one hence why it is not quite finished yet.  

I hope you have found this tutorial helpful. Enjoy making your half square triangle projects!  

Michael Miller fabrics were used for this project;

• Cotton Couture Solids- black and white for the background.
• Berry Frost Fabrics for the hearts.