Chain Piecing Half Square Triangles

I have been making half square triangles like a mad woman lately.  I have a new pattern that I have designed and I am really excited about it.


I know I have been through the process of making HSTs several times, and today will do it one last time so I can refer back to this post for future patterns.  Here’s a look at the current crop of HSTs.  When I get this lap size quilt fully assembled and quilted, then I will share it and the table topper you’ll see coming up with my Easter tablescape.  But first….


let’s do HSTs!

Mystery Scrap Quilt -1

I use only Aurifil 50 wt thread for piecing.  I love that it is thin and strong, and I believe it gives more precision to your work.

Start by cutting your squares to at least 3/8″ (and I do 1/2″) larger than you want the finished HST to be.  In other words, if you need the HSTs to be 2-1/2 inches for piecing the next step, cut the squares 2-7/8 to 3 inches square.

Mystery Quilt 2015 - The Fabrics

Draw a diagonal line from one corner to the opposite corner on your lighter color fabric.

Mystery Quilt 2015 - 3

Pair the two colors together. Many times this will be the focus fabric and the background fabric.

Mystery Quilt 2015 - 8

Sew 1/4″ away from the line on both sides.

Mystery Quilt 2015 - 4

Chain piece by setting up all your squares, then running them one after another through the machine. The chain makes sewing the seam on the other side really easy as they are all together.  Just turn the chain around and sew 1/4 inch away from the other side of the line.

Mystery Quilt 2015 - 5

Cut the pieces apart from each other, then cut on the drawn line to yield two HST units.

Mystery Quilt 2015 - 6

Press toward the darker of the fabrics. Square up to the correct size, placing the 45-degree line along the diagonal seam and trimming all four sides.

Mystery Quilt 2015 - 7

That’s it!  No need to be afraid of a lot of HSTs any longer.  Quilts are so much more interesting with these angles as part of the design.  Next time you see a pattern with a lot of HSTs, be confident, you can do it.

Update – I have discovered that my HST piecing is even more accurate if I mark the actual sewing lines.  I use this quarter-inch ruler, lining up the line in the middle of the ruler with the corners, and marking the sewing line at a precise 1/4-inch.  Sewing on the edge of the line nearest the center gives me a more accurate half-square triangle unit.

Sewing Scrap Dance Waltz HSTs ~ From My Carolina Home

Happy Quilting!


9 thoughts on “Chain Piecing Half Square Triangles

  1. I have loaded the Scrap Dance Quilt Along button on to my blog and checked. It works. When I get some time I will share my HST units on Flickr. Still have more to make.

  2. HST’s are a good addition to any quilt pattern. I like my Tucker Trimmer fro sizing my blocks. How do you find a Technical writer? Congrats on making a new Design.

  3. Adri

    Wow now that’s interesting I’m new to quilting and I love it. This fast and easier way is going to work for me! Thanx

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