The Pinwheel block is a beautiful traditional block made up of four Half Square Triangle blocks.
Each Pinwheel Block is made from 4 squares of two different fabrics. You will need two squares of each fabric. The squares in this example are 6 1/2-inches.
Lay one small square with the right side up. Place a second piece on top with the right side down and the stripes parallel to the first square’s stripes. Repeat with remaining two squares.
With a pencil and a straight edge ruler, mark a line from the upper left corner of one of the square stacks to the lower right corner. Pin fabrics in place on each side of marked line.
On the second stack of squares, mark the line from the upper right corner to the lower left. Pin fabrics in place on each side of marked line.
NOTE: The example block is made from striped fabrics which is why the two stacks of squares are marked in opposite directions. If you are using non-striped fabric you can mark both stacks in the same direction.
Sew a seam ¼ inch along each side of the marked lines on both squares.
Cut along the marked lines of both squares. You now have four pieces.
Open up the pieces and press the seams to one side. Since the fabrics are the same or similar, it does not matter which direction you press the seams, but make sure to press them toward the same fabric on all four squares.
Trim any seam allowance that extends beyond the corners.
Lay out the four pieced squares as shown above. If you are using stripes make sure that all adjacent stripes are perpendicular to each other.
Lay the top right square over the top left square with proper sides together. Align and pin the right side edge of the two layered squares.
Repeat to join the two bottom squares.
Sew along the pinned edges and press open with seam allowances to one side.
Lay the top right square over the top left square with proper sides together. Align and pin the right side edge of the two layered squares. Repeat to join the two bottom squares.Sew along the pinned edges and press open with seam allowances to one side.
With right sides facing, align and pin together the edges of the top and bottom halves of the pinwheel, carefully matching up the points at the center.
Sew along the pinned edge, making sure that the seam meets the tips of the pinwheel points without sewing through them.
Press the seam open.
The block is done!