I just discovered a new and easier way to make nice pinwheels. This is something I'm doing for my newest baby quilt. Let me share it with you. This measurement makes a pinwheel 6" finished size.
Start with 2 squares 5 3/4".
Sew around all 4 of the outside edges 1/4".
Cut diagonally twice through the square.
If you open it up as it is laying, it will look like this.
Rearrange them to make your pinwheel.
Sew the 2 top squares and the 2 bottom squares together. Press towards the dark fabric.
This is what they look like then. Sew the top half to the bottom half.
When it's sewn I make 2 slits at the center 1/4" on each side of the seam.
I smash it open with my finger and then press it. This gets rid of that big lump in the center.
I trim the piece to make a 6 1/2" square.
Now I have some lovely squares waiting to be added to and put together.