Quilt Class: Triangles

Now it is time for triangles. Triangles are not hard but you do have to pay attention to the bias. There are different types of triangles and in this block you will make Half Square Triangles. Understanding how to sew triangles expands your repertoire of designs by leaps and bounds.

Double Pinwheel
Double Pinwheel

You will make a 12 inch finished Double Pinwheel block. This block is also a 2×2 grid, just like the Double Four Patch. The pinwheels make up one square in each row of the two by two grid. Plain blocks make up the other squares.

Supply list:

  • fabric
  • rotary cutter
  • rotary cutting ruler
  • rotary cutting mat
  • fabric (2-3 different)
  • Mary Ellen’s Best Press (or similar) is very helpful with the bias
  • pins
  • sharp scissors
  • thread for piecing
  • sewing machine
  • Iron
  • ironing surface
  • Optional: numbered pins


Double Pinwheel - Another View
Double Pinwheel – Another View

1. Cut:

  • 4 squares 4in. x 4in. for the blades of the pinwheel AKA the triangles. Mine are red in the above photos
  • 4 squares 4in. x 4in. from the background fabric. My background fabric is aqua in the above photo. This size will allow you to have enough extra fabric to trim the half square triangles before you sew them into the pinwheel. I like trimming
  • 2 -6.5in. squares from the background fabric for the plain background squares.

2. Cut all of the 4in. squares in half on the diagonal.

Layout your patches
Layout your patches
Layout your patches

3. Lay out all of your patches on your design surface so you can see how the block will look.

The cut patches look like they won’t fit.  That is because of the seam allowances. It will all work out in the end. I promise.

4. Put one background triangle and one pinwheel triangle right sides together matching the hypotenuse (longest side) of the triangle.

4A. Spray the two fabric patches with Mary Ellen’s Best Press. Handle the triangles carefully by not yanking on them.

Gently put triangles under presser foot
Gently put triangles under presser foot

5. Sew one background triangle and one pinwheel triangle together along the hypotenuse of the triangle. I sew them with the background patch on top.

Use your hands to guide not yank
Use your hands to guide not yank

Sew all patches with the same color fabric on top. It will help you keep them organized.

My fingers are just keeping the hypotenuse up against my seam guide. The feed dogs are moving the fabric.

Chain piecing, baby!
Chain piecing, baby!

Sew one triangle after the other without clipping the thread between them. This is chain piecing. I use chain piecing to piece all of the triangles. I try and prevent them from falling off the back of my table so the falling triangles don’t yank on the ones still under the presser foot.

6. Sew all triangles needed to make pinwheels. Take them out of the machine and clip the threads between.

7. Take all of your sewn triangles to your pressing surface. First, I set the seam like Fons & Porter suggest and then open the seam and carefully press the seam towards the pinwheel fabric (red dot in my case).

8. Take the pieces to your cutting mat. Line up the diagonal line on your ruler (hopefully you are using a square ruler with a diagonal line) with the diagonal line you have sewed and trim your new half square triangle (HST) block to 3.5in.

  • You will need to make this cut twice for each patch as you cut two sides. Trim the top and the right side first. Then, turn the block 180 degrees and then trim the other two sides, which are, once again, the top and the right side.

9. Arrange your sewn HSTs on your design wall to you can be sure that they are arranged in a pinwheel block.

10. Make a note to yourself (use a pin, eyeball it, pinch it) which sides you are going to sew together. Nota bene: This is where numbered pins come in handy, if you decided to buy them.

Sew 2 HSTs together
Sew 2 HSTs together

11. Take 2 half square triangles and place them right sides together underneath your machine’s presser foot.

Nested HSTs
Nested HSTs
  • The seam allowances on the diagonal should be nested together. This will work if you have pressed all of your HSTs towards the pinwheel fabric. In the above photo you can see how the diagonal seams are lined up when I lift the corner of the fabric to show you. (Professional stunt quiltmaker! Please do not try this at home with your machine running!!!)

12. Making sure you are sewing them in the right orientation, sew two half square triangles together.

13. Press these half pinwheels towards the background.

  • You should have 2 pieces of 2 half square triangles ready to sew into a pinwheel.
Important Matching Spot
Important Matching Spot

14. Nest the 2 half pieces together. In the above photo I have put the pin in just to show you about where you should sew. Sew along the middle of the pinwheel

  • When you sew try not to cut off the point of the pinwheel center. You will see a V made by the seams you have sewn previously. Make sure you err towards the seam allowance (on your right looking at the needle of the sewing machine) and don’t cut off that V. Ideally, you want to sew one thread towards the seam allowance on top of that V.
  • You can just sew over the middle (.5in. on either side of the middle point) to make sure your points match, then you can go over the whole seam once you decide if you like the way the center looks. The ripping out is easier if you only have an inch to do.
Middle Sewn to Check Points
Middle Sewn to Check Points

When you open the block (with just the middle sewn) you can tell whether or not the center point will match.

A NOTE ABOUT POINT MATCHING: It is really important that you know your tolerance level for points not matching. My points don’t always match and either I leave them or rip them out. If my points are 1/4inch apart, I usually rip them out. If they are 1/16th of inch from one another, I will probably leave them. It is important to know:

  • what you are trying to achieve (practice block or show quilt)
  • if you are going to think about that seam not matching late into the night and it is going to prevent you from sleeping.
  • deadlines
  • whether the quilt is a gift to a prize winning quiltmaker or a baby who will drool all over it.
  • How busy the fabrics are (can you actually see the seams matching?)

Be kind to yourself when you think about whether to agonize over a seam not matching. Have fun, there is always more fabric and don’t make yourself crazy.

15. Sew the halves together, along the whole side, for both pinwheels. If you have sewn along the middle for an inch, make sure you stay on that line when you sew the whole side together.

Pressing Perfection
Pressing Perfection
  • See that nice little square that the pinwheel makes in the center? That means you did it right!

16. Press the pinwheels patches in the same direction as the other triangles. It will look like the seam allowances are spinning. It will also make less bulk in the center of the block.

17. Sew the large 6.5inch background square to each of your pinwheels. Pay attention to which side of the pinwheels they are sewn.

18. Press towards the 6.5inch square/background.

19. Nest the two pieces (which are made up of a pinwheel and a background patch).

20. Sew over the middle  starting from about .5inch on either side of the middle to make sure your seams match and you have not cut off points.

21. Sew the 2 pieces together starting on one side, sewing over the middle where you have already sewn and continuing to the end of the block.

View of Pressing
View of Pressing

22. Press whichever way the seam seems to want to go. I like to press each half of the seam towards the background. It makes for kind of an ugly pressing job, but I am not going to quilt over that center anyway, so, for me, it doesn’t matter. Pressing this seam open also works.

  • You could trim the seam in the middle, but I don’t do that. Jo Morton talks about doing that and you might want to check out her website and YouTube videos.

    3 Sampler Blocks
    3 Sampler Blocks

Look how nice the 3 blocks look together!