Thursday, February 27, 2020

How to Make a Half Square Triangle - 8 at a Time

Half square triangles are one of the most common units in patchwork quilting. It consists of two 90 degree triangles sewn into a square.

Once you start looking, you'll see the half square triangle in many different quilt blocks.

Last month, I shared how to make half square triangles two at a time. But for those projects where you need lots of them, I recommend trying this 8 at a time method.

 I used all these HST's for a shoo-fly quilt block
8 half square triangles on a painted wood backdrop

This method works great for a bear paw block too!

Sometimes it's called the magic 8 method. You begin with two squares of fabric and sew 4 seams along the diagonals. Cut the material in specific directions and magically, you will have 8 half square triangles.

Don't need 8? Try this 4 at a time method.

Keep reading for all the details!


↓ ↓ ↓ PIN IT ↓ ↓ ↓ 
image with 8 half square triangles with text overlay
↑ ↑ ↑ PIN IT ↑ ↑ ↑

This post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases. Please see my full disclosure policy for details. 



In order to end with the desired size of half square triangles there's a formula.

Finished size + 1 inch X 2 = Size square to cut

Many quilters add 7/8 of an inch instead of a full inch. But that just makes the math too complicated for me. Plus that extra 1/8 of an inch allows you to square up your pieces for optimal fit when piecing.

But you don't need to do the math! I've created a little cheat sheet for the most common block sizes. Go ahead and print it out for future reference.

half square triangle cutting chart

To print either click the ↑ image ↑ or this ↓ link ↓
Printable Cutting Chart for Half Square Triangles


Let's get started. As always, I have step-by-step pictures. Be sure to watch the video if you learn better that way.
collage of steps to make half square triangles
Begin with two equal sized squares of fabric. I like to use a darker fabric and a lighter fabric.

Place the darker fabric right side up. Lay the lighter fabric directly on top with the right side facing down.

Note: For this project I'm starting with 6" squares. The half square triangles will be trimmed to 2 1/2". Once sewn into the block their final size will be 2". Use the chart above to create the size HST's you need for your project.
tracing and sewing half square triangles

Now, take a straight edge and place it on top of the square corner to corner. Draw a line with a pencil. Repeat with opposite corners.

Sew along both sides of both lines. Use a 1/4 inch seam allowance.

collage depicting how to cut half square triangles
Next, we'll cut the square into four smaller squares. Cut both vertically and horizontally. Make sure you measure to be sure you cut them squarely in the center.

Next we'll cut each of the smaller squares into triangles. To do this cut along the drawn line.

8 half square triangles

Press them open and square them up. Now they're ready to go into a quilt project.

Want to watch the video?  ↓↓Click the link ↓↓


Don't forget to pin it!!
magic 8 half square triangle tutorial

No comments :

Post a Comment