Quilt Along

How to Make a Pinwheel Sawtooth Star Quilt Block

One of my favorite blocks, or units of a quilt block, is the half square triangle, and this fun block is made up almost exclusively of them. They add so much movement to the design. If you like this block as much as I do, then here are instructions on how to make a pinwheel sawtooth star quilt block.

This pattern is for a big block, 18 1/2″ square to be exact. It makes a great mini quilt or, if you want to make a larger size quilt, you don’t need too many of them. And yes, if you follow my blog you know I love a scrappy look, and this block is good for that.

In fact, if you are following along with my 2021 Stars of the Prairie mystery quilt, you know that, with the exception of the pale green background, I have only been using fabric from my stash. This is the fourth (April) block for the mystery quilt and we are making one of them.

If you are here for the quilt block tutorial, but not for the mystery quilt, then scroll down a little bit for the instructions.

*Download the Pinwheel Sawtooth Star Quilt Block Pattern Here*

April Mystery Quilt Info

Please read all instructions carefully before beginning.

We will be making one block this month. Use a scant 1/4″ seam allowance throughout.

Supplies Needed

Along with the fabric, you will need some general quilting supplies.

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How to Make a Pinwheel Sawtooth Star Quilt Block (18 1/2″)

Fabric Needed (Generous Amounts are Given):

Background Fabric: Fat quarter, Fabric A: Fat quarter, Fabric B: Fat quarter

Cutting Instructions:

Background Fabric:

  • 4 squares cut 5 inches by 5 inches
  • 4 squares cut 5 ¾ inches by 5 ¾ inches

Fabric A:

  • 4 squares cut 5 ¾ inches by 5 ¾ inches

Fabric B:

  • 4 squares cut 5 ¾ inches by 5 ¾ inches

Video Tutorial

Block Assembly:

To make the half square triangles you will need all of the 5 ¾ inch squares. Match them up as follows:

Background with Fabric A: 2 pairs

Background with Fabric B: 2 pairs

Fabric A with Fabric B: 2 pairs

On each of the pairs, draw a diagonal line on the back (wrong) side of the lighter fabric. This will be your sewing guide.

Line up each pair of squares with front (right) sides facing each other.

Using a ¼ inch seam allowance, sew along both sides of the drawn diagonal line.

Cut down the center, along the drawn line. You will end up with two blocks that need to be pressed open.

Trim the blocks down so they measure 5 inches by 5 inches. Repeat with the remaining pairs. You will have a total of 12 half square triangles.

Lay out the units as shown.

Sew the block together by sewing the individual rows and then sewing the rows together. The block should measure 18 ½ inches when finished.

Because or the center pinwheel, this block has a lot of movement to it. You can also add a fourth fabric if you want to change things up a bit. I did that with my purple tester block below.

My April tester block – a whole lot of purple going on here!

If You Are Participating in the 2021 Stars of the Prairie Mystery Quilt:

You just need to make 1 of these blocks.


Feel free to join in the mystery quilt fun. You can find all of the details in this article.

In addition, I have this FB group for people who are participating. It’s a fun place to see what other people are doing for their blocks.

What we’ve done so far:

Show off your progress on social media! Make sure to use the hashtag #createwithclaudiaqal if you post any pictures!

*This mystery quilt along is for entertainment purposes only. Therefore, there are no prizes or giveaways.* Best efforts have been made to ensure that the instructions are correct, however sometime errors occur. If you have any questions, please contact us *

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