Originally Posted by
JustAbitCrazy
Sally Collins, author of a book on precision machine piecing, recommends you have the entire narrow black line (not the fat yellow line around it) on the fabric, without showing any fabric beyond the line. The thickness of that line makes up for the thickness of the thread and what is lost when you turn the seam allowance to one side, so in cutting that way, there is no need to sew a scant quarter inch. She has lots of other tips for accuracy in quilting. I highly recommend her book and workshop.
A quilting friend of mine told me this over 8 years ago. I was sitting the Omnigrid black line in the middle. Once I started doing this. I found that my blocks were much more accurate. Remember, you loose a hair of fabric when you press a seam to the side. Hope this helps you like it helped me.