Here we have the Pinwheel Star from the Delaware Quilts Block of the Month. The way I look at a quilt block to figure out how to make and size it, is first to look at the grid it fits on and then the factors for the units and pieces needed to make the quilt block.
4 Patch Grid with factors of 2, 4, 8
In this case the grid for this block is a 4 patch with unit factors of 2, 4 and 8. So let’s say I want to make a 12 inch finished block, I’ll take 12″ ÷ factor of 2 = 6″ + ½” seam allowance = 6½”. Repeat this for each of the remaining factors.
factor 2 = 6½”
factor 4 = 3½”
factor 8 = 2″
There are 3 basic units in this quilt, half square triangle units, tri square triangle units and flying geese units. The half square triangle units are factor 4 size, the tri square triangle units are also factor 4 size, however, two of the pieces are factor 8 size. Lastly, the flying geese unit is factor 2 size by factor 4 size.
4 half square triangle units from 3½” strips
4 tri square triangle units from 3½” and 2″ strips
4 flying geese from 3½” strips with the larger piece at least 6½” long depending on your method of making this unit.
All of the units in the Pinwheel Star block are pretty basic units and there are many, many methods of making each of these units. Just choose your favorite and now you have all the information you need to make your block.