Originally Posted by
Tartan
When doing snowball blocks I do the method where I put a little square on the corner of the big square. I mark the diagonal on the little square, sew next to the line (on the outer edge ) and fold out the square. If the folded triangle makes the perfect size of the big square , I trim off the extra corner piece. Yes it wastes a little fabric but it works for me.
I do this method too and yep. Do not sew on the line for those little squares. Reason is the thread and the folding of the seam use up a bit of fabric and if you stitch right on the line, your little corner triangle will be too small to line up with the larger square. I would actually make a few test snowball blocks, you may have to stitch that seam even a little more to the outside edge depending on the thickness of the fabric and the thread. If the blocks are not that large, I may even not trim the waste corner triangles off as I will use the edges of my larger fabric to guide my seam lines as my piecing will be a bit more accurate that way. Leaving those waste triangles usually doesn't leave too much additional bulk if it is on smaller block