Ready for the next filler block? It’s time for the pinwheel!

Jeanne and I went into great detail on this block, so this is just a matter of providing measurements. Choose your favorite method for creating half square triangles from these posts:

Skill Builder Series: Part 1A – Half Square Triangles and Pinwheels
Skill Builder Series: Part 1B – Half Square Triangles and Pinwheels

Any of the methods will work, and since you need create two different sizes of pinwheels, you can try several methods to find your favorite.

If you’re following the white and bright layout, you will need one green 6″ pinwheel, three red 4″ pinwheels, and three yellow 4″ pinwheels.

6″ Pinwheel

This is the size that both of our HST posts used, so refer to those posts for all measurements and instructions. If you’re interested in trying the Triangle Papers method, here’s your chance. I provided a PDF and instructions for making 3″ finished HSTs in this post.

4″ Pinwheels

For each pinwheel you will need 4 HSTs that finish at 2″ (2 1/2″ unfinished). Important: One pinwheel will not be fully assembled! You will create two halves, and they will be incorporated into two different blocks. When the blocks are put together, the pinwheel will be completed.

Method 1: Triangles

Skill Builder Series: Part 1B – Half Square Triangles and Pinwheels
This is the original method, cutting squares in half diagonally (exposing a bias edge) and then sewing them together. I don’t recommend this method other than as an experiment, so you can see how much easier the other methods are.

If you use this method, you will need (for each pinwheel):
Two 2 7/8″ background squares
Two 2 7/8″ block fabric squares, cut diagonally once
If you prefer to cut slightly larger then trim to size (which I recommend), cut the squares at 3″ or even 3 1/4″. Trim the resulting HSTs to 2 1/2″ before assembling your pinwheels.

Method 2: Strips

Skill Builder Series: Part 1B – Half Square Triangles and Pinwheels
This method works best if you are making a lot of the same HSTs, so it’s ideal for multiple blocks like this.

Cut a 3″ wide strip width of fabric of background fabric.
Cut a 3″ wide strip of block fabric.
If you make all of your pinwheels from the same fabric, you can get all of your HSTs from one strip width of fabric. If you are using two different fabrics, you’ll need two different block fabric strips 3″ x 20″ (this leaves a little extra room). You need a total of 24 HSTs, or 12 of each color.

Draw vertical lines every 3″ and then draw the diagonal lines connecting them.

Trim the resulting HSTs to 2 1/2″ before assembling your pinwheels.

Method 3: Triangle Papers

Skill Builder Series: Part 1A – Half Square Triangles and Pinwheels
This method is best for making a lot of the same HST, so it’s ideal for multiple identical blocks like this.

Use Triangle Papers, Thangles, Triangles on a Roll, or Triangulations software to create 24 HSTs that finish at 2″. If you’re doing two different fabrics, you’ll need 12 HSTs from each fabric. Papers for this size are NOT provided, so if you don’t have the paper, this method won’t work for you.

Method 4: Squares with Diagonal Lines

Skill Builder Series: Part 1A – Half Square Triangles and Pinwheels
This method is best if you are making each pinwheel (four HSTs) in a different fabric.

For each pinwheel you will need two background squares and two block fabric squares cut at 3 1/4″ (this will allow extra fabric for you to trim it to size). If you’re confident in your accuracy with cutting and quarter inch seams, you may choose to cut at 3″ instead. Trim the resulting HSTs to 2 1/2″ before assembling your pinwheels.

Pinwheel Assembly

I went into EXTREME detail in this post for turning your collection of HSTs into pinwheels, so there’s no need to re-write it all!

If you like, try making your pinwheels “spin” in different directions by rotating the HSTs 1/4 turn before sewing them together. The final version of the sampler includes one “backward” pinwheel – can you find it?

Remember, one of your 4″ pinwheels will not be fully assembled. Sew the two halves together, but do not complete the final seam.

How is it going – any questions so far?