A Guide to Sewing Quarter Square Triangle Quilt Blocks Quickly - 4 at a time!

Let’s chat quarter square triangles (QSTs) patchwork quilt blocks made up of four triangles that come together in a neat, symmetrical design. You’ll spot them in loads of traditional quilt designs, and they’re brilliant for adding interest to your patchwork projects.

In this post, I’m sharing a quick method to sew them without having to cut small triangles from the start. It’s fast and satisfying, but like all good shortcuts, it comes with a tiny catch: the outer edges of your finished block will be on the bias, which means they’re a bit stretchy and can get wonky if you’re not careful. Don’t let that put you off though, I've got a few tips to help you keep everything nice and square -

1. Press, don’t iron When pressing your seams, lift and lower the iron rather than sliding it across the fabric. Bias edges stretch easily, so ironing can distort the shape of your block.

2. Use starch or pressing spray A light mist of starch or a pressing spray like Best Press can help stabilise your fabric before and after sewing. It gives the fabric a bit more structure and helps reduce stretching.

3. Handle pieces as little as possible Once you’ve cut your bias-edge pieces, try not to over-handle them. The more they’re moved around, the more chance they’ll warp. Cut, sew, and press with purpose!

4. Pin carefully (or use clips) Because bias edges are stretchy, they can shift as you sew. Pin (or clip) at the start, end, and along the seam to help keep things in place, especially if you’re joining to a straight edge.

5. Sew with a gentle hand Try not to pull the fabric through your machine. Let the feed dogs do the work, and just guide the fabric gently. If you're tugging even a little, bias edges can stretch and skew your seams.

6. Square up your blocks After you’ve sewn and pressed your quarter square triangles (or any block with bias edges), take the time to square them up with a ruler. This will help keep everything neat and make piecing your patchwork much easier.

I'm using two 12" squares to begin with which creates four QST blocks with a finished size of 7.5" if trimmed down at the end. (the finished size is just under 8")

1. Place two 12" squares with right sides together. Sew around the entire edge using 1/4" seam allowance.

2. Cut diagonally from one corner to the opposite in both directions.

3. Open and press the seams. Trim to 8". These are now half square triangles!

   

   
   

4. Place two of the half square triangles with right sides together, matching opposite fabrics and lining up the centre seams.

   Draw a diagonal line in the opposite direction to the seam.

Sew 1/4" down both sides of the line drawn.

5. Cut along the line. Then open and press each one.

   Repeat with the remaining squares to get 4 quarter square triangle blocks!

   

   
   

And that’s how you make quarter square triangles the quick way! Once you get into the rhythm of it, you’ll have a stack of blocks ready in no time. Just remember to handle those bias edges gently, no tugging or over-pressing, and your blocks will behave beautifully.

The fabric that I've used for my blocks in the Liberty Quilting collection called London Bouquet. It was kindly gifted to me in fat quarters to use in a sewing tutorial.

QSTs are such a versatile shape to have in your patchwork plans, and I hope this method helps speed things up for you. If you give it a try, tag me @whatkimberleymakes so I can see your lovely makes!

Happy stitching!

Kym x