How to Make
Individual Half Square Triangles

Technique #2 - Creating a HST plus a bonus unit

by Julie Baird

This post contains affiliate links for which I receive compensation.

Make a half square triangle plus a bonus

Half square triangles are one of the standard units for patchwork piecing.

Quilting books also refer to them as a triangle squares or abbreviate it as 'HST'.

This unit is a square made from two equal right triangles.

The diagonal seam through the middle is on the bias while the outside edges are all of the straight of grain for stability.

Create a Half Square Triangle Plus...
a Bonus Unit from Squares

For this technique, you'll sew two squares together with one seam and create a single triangle square unit.

Pros:

Method creates a single triangle square unit
No 'magic numbers' to remember
No special templates, tools or triangle paper needed
Cut from the same size strips as other patches are
Adding a second seam creates a bonus HST to be used later

Cons:

If you don't intend to use the 'bonus' triangle, there's a lot of waste
Each patch is individually marked
There are faster methods for creating multiple identical units

Now, let's get started!

The Technique

The Formula

Cut two squares equal to the finished size plus 1/2" for seam allowances.

Step 1

In this example, we want a 3-1/2" finished HST unit, so we cut two squares 3-1/2" plus 1/2" or 4" x 4".

Step 2

Mark a diagonal line from corner to corner on the back of the lightest square. This line need only be as dark as you need to see it. Take care not to 'pull' on the bias with your pencil. (I've used the Bohin Mechanical Chalk pencil in white in the picture below. This chalk pencil is my first choice for a marking tool because it produces a consistently fine line.

Step 3

Layer the two patches right sides together, aligning all the edges. Stitch on the line from corner to corner.

Sew the half square triangle diagonally from corner to corner

Step 4

If you're a scrap quilter, then stitch a parallel line, 1/2" from the first. This creates the 'bonus' triangle with enough fabric for seam allowances for both units.

Note the scrap piece of fabric. Sometimes your sewing machine wants to 'eat' the points of these squares. To eliminate this problem start by sewing onto a scrap first and then onto your squares. I call this scrap a 'spider', others call it a 'bunny tail' or anchor cloth. I'm sure there are more names...

It also helps to starch your quilt fabric before stitching.

Stitch a second line to create a bonus half square triangle

Step 5

Press the unit flat to set the seam.

Step 6

Cut the sewn squares in two between the stitching lines.

If you chose not to create a bonus unit, then trim away the excess fabric 1/4" from the stitching line on one side.

Step 7

Finger press along the seam line to minimize the chance of a tuck forming. Press flat with your iron and trim off the dog ears. The dog ears have been trimmed from the larger triangle square (below, left), but not from the smaller, bonus unit (below, right).

Press the half square triangles open and remove the dog ears

The final triangle unit is 4" unfinished (the same size as the cut squares because you stitched down the center diagonal) or 3-1/2" finished. The bonus unit is approximately 3-1/4".

Admittedly, at some point, the bonus triangles just get too small.

But with larger half square triangles, you end up with a nice bonus unit with little extra work. Keep them neatly stored and trim just before using in your next scrap quilt.

More Half Square Triangle techniques to try...

Sandwich or Quick Pieced

Make one half square triangle plus a bonus

No mark, 4 at a time

8 at a time

Specialty Rulers

Half Square Triangle Paper

More Triangle Paper Options

Itchin' to stitch?

Now that you've got two different methods for making HST's, check out our Free Quilt Block Patterns library and put your skills to good use!

For even more blocks to make...

These are my go-to resources for quilt block ideas.

Can you see the library sticker on the spine of Jinny Beyer's book? Yep. I check this copy out of our local library every few months for research.

Maggie Malone's 5500 Quilt Block Designs is my all-time favorite quilt block resource!

Can you tell?

It's in color.

It's got a ton of blocks.

What's not to love?

Next on my 'must-have' list is Barbara Brackman's Encyclopedia of Pieced Quilt Patterns.

Unlike the Maggie Malone book, the blocks in this volume are hand-drawn and in black and white—no color—personally, I prefer colored drawings to work with.

This book is no longer in print. If you can come by a copy expect it to be wickedly expensive.

However...

BlockBase is the computerized version of the Encyclopedia.

It can be used with Electric Quilt and is a Windows based program.

Finally there's The Quilter's Album of Patchwork Patterns by Jinny Beyer.

Lots of detail and in color, it is a beautiful volume. That said, I check it out of my local library on a regular basis instead of purchasing it—can you see the library sticker on it's spine. Yep, it's from the Plainfield Public Library.

Why?

Simply because I own the previous three references and find this the least user-friendly of the group.

And it does make a fabulous coffee table book!