Making quarter square triangles the easy way

Are you caught up to cutting and sewing 100 half square triangles from yesterday’s post? Have you tried my tip on the 1 way to avoid finicky measuring when making HSTs?

I’m loving the Northcott Canvasfabric colors, looking forward to the seeing it finished!

Half square triangle blocks made using Northcott Canvas fabrics.

Today, we’ll make 100 quarter square triangles (QSTs) using the 100 5⅜” x 5⅜” square fabric pieces we cut yesterday.

100 – 5⅜” x 5⅜” square fabric pieces that will be made up into 100 QSTs.

As with the HSTs we made yesterday, quilting reference books have something to say about QSTs.

Compared to yesterday when you added ⅞” to the finished block size to make an HST, today you need to add 1¼” to the finished size.

In other words, if your finished block size is 4” x 4” then cut 5¼” x 5¼” square. As I mentioned yesterday, if you have the perfect ¼” seam and your fabrics were cut perfectly to size, then yes, your finished square once sewn and pressed open will be 4½” x 4½” unfinished square.

I don’t know about yours but sometimes my seams are a little off, so, my 4½” x 4½” square would be off. To ensure that I get the result I want I add an extra ⅛” to give me a slightly larger fabric square. My work around? Instead of cutting my fabric squares 5¼” x 5¼”, I cut them 5⅜” x 5⅜” square. After all the trimming is done I get perfect results!

Fabrics squares cut 5⅜” x 5⅜” square.

Now we need to separate the 5⅜” x 5⅜” squares.

Now to make two piles of squares:

  • Pile 1: 50 – 5⅜” x 5⅜” squares: 25 cream, 12 orange, 8 yellow and 5 red
  • Pile 2: 50 – 5⅜” x 5⅜” squares: 24 red, 16 lime green and 10 green

On the back of every piece of fabric from Pile 1 draw 2 diagonal lines going from corner to corner to corner as in the photo.

Make diagonal lines on the back of every piece of fabric from Pile 1.

Once we’ve added the diagonal lines, we’ll pair the fabric squares with those from Pile 2 as follows:

Pile 1

Pile 2

5 cream squares with 5 green squares
8 cream squares with 8 orange squares
12 cream squares with 12 red squares
12 orange squares with 12 red squares
8 yellow squares with 8 orange squares
5 red squares with 5 green squares

Now we need to sew. If you look at a piece of fabric with the diagonal lines drawn on, we can see that the square is now divided into quarters. We’ll only sew on one side of the diagonal line and only up to the intersecting diagonal line (1 seam in each section/quarter), as shown in the next photo.

One seam per quarter

Now use a rotary cutter or scissors to cut along each diagonal line.

Cut the squares into quarters by cutting over diagonal lines.

Pair all of these pieces together as follows, (like piecing a puzzle together!)

  • 10 cream-green pairs and match with 10 red-green pairs
  • 24 cream-red pairs and match with 24 orange-red pairs
  • 16 cream-orange pairs and match with 16 yellow orange pairs

Paired quarter pieces.

After the pairing is complete, sew both halves together then press.

The sewn halves

Finally, as we did yesterday, we need to trim our QSTs to a perfect 4½” x 4½” square.

Square off each piece to make a 4½” x 4½” square.

We’ve come to the end of another day of sewing and trimming to get the 100 QSTs we need for this quilt!

I know you’ll be back tomorrow as we put the blocks together to complete the quilt top. It’ll be amazing to see how all of these vibrant Northcott Canvas fabrics look when they’re all sewn together. 

This is part 3 of 5 in this series.
Go back to part 2: 1 way to avoid ‘finicky measuring’ when making Half Square Triangles

Go to part 4: A refreshing take on the Ohio Star block using bright colored Canvas fabric

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16 comments

Susan February 21, 2020 - 1:56 pm
Thanks, Paul! I thought I had the easiest way to do this, but you simplified it even a bit more. I just used your method to make parts of a square with 96 pieces, and the QST are the most excellent part of the block. LOL I will refer my friends to this post in the future.
Pamela R March 6, 2018 - 3:02 pm
I so could have used this ...yesterday!
Dee February 12, 2018 - 3:21 pm
This is a bit of quilting magic ... thank you!
Cassandra D February 11, 2018 - 8:44 pm
I have to try this method.
Cecilia February 8, 2018 - 7:58 pm
Thanks for the great tips for cutting perfect quarter square triangles.
Paul Leger February 9, 2018 - 12:21 pm
you are welcome
Carla C February 8, 2018 - 6:58 pm
Thanks for the info. Everytime I try to cut triangles , they're always off by a few millimeters.
Paul Leger February 9, 2018 - 12:22 pm
same here, that is why I add that 1/8", helps me get a perfect square
bn100 February 7, 2018 - 10:46 pm
helpful tips
Elizabeth Matthiesen February 7, 2018 - 9:05 pm
I do enjoy all these tips that you share, they certainly help to make life easier.
Paul Leger February 9, 2018 - 12:23 pm
glad you are enjoying them, come again as there are many more
Laura G February 7, 2018 - 3:33 pm
Thanks for this tip! HST are always a challenge for me and my imperfect 1/4" seam guide. And my inability to mark a straight line even with a ruler.
Paul Leger February 9, 2018 - 12:23 pm
this tip means a bit more work but the result at the end is so much nicer
Lynda Hermann February 7, 2018 - 12:57 pm
love this method - must try it out!
Paul Leger February 9, 2018 - 12:24 pm
you'll love it
na February 7, 2018 - 7:53 am
What a cool trick!
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