Today I am hosting the Block of the Month tutorial for Bay Area Modern. You can see the rest of the blocks on the BAM blog.
This block is an easy twist on the traditional pinwheel block (also called turnstile). The asymmetrical cropped point is super simple to implement, making this a quick block to sew.
I recommend starching your fabric pieces before you begin because there is a lot of bias sewing in this block. I use Best Press and press all seams open.
Stack the two middle size background fabrics together and cut once on the diagonal. Cut the other three squares in half twice on the diagonal to get four triangles. All your pieces should look like this:
Fold the smallest triangles in half and use your fingers to make a crease mark. If you are using a print fabric for the background, fold it with the right sides together.
Place the creased triangles on top of the foreground triangles, aligned at the corner. With the 90° corner toward you, the triangles should be aligned on the right (as shown).
Sew the triangles together just to the right of the crease line. If you are making a 12" block, you may wish to sew a second line 1/2" to the left. That second line sews your trimmings together into half of a 3" quarter square triangle. The 6" block trimmings are kind of small to bother sewing up.
Trim off the excess at the corners with a 1/4" allowance and press the seam.
Sew a medium triangle of background fabric to each triangle, along the short pieced edge. Press.
Sew a larger triangle of background fabric to each piece, along the long edge. If your triangles are not exactly the same size, that's fine. Make sure that they line up at the inside point and everything will be good. Press.
Sew your squares together in twos. Trim the inside corner seam allowance before pressing the seam open to avoid bulk at the center point. I aim for an approximate 60° angle.
Sew the two block halves together. This is the part where I use pins. Double pin the center for the best possible point. Go slow along the center section and make sure your needle goes down just the smiiiidgiest smidge to the right of where the points meet. Press.
You should have a bit of extra fabric to trim off to get a perfect 6.5" or 12.5".