Originally Posted by nantucketsue
I don't understand why when they made the 1/4" foot they didn't just allow for the thread width. It does make a difference.
The person who writes the directions is trying to cover all bases. Part of the problem is the fabric itself. It's not so obvious with quilting cotton but if you go to other fabrics it's easier to understand.
Compare silk to canvas. OK extreme examples. Imagine sewing three strips of silk together, press to one side. Now imagine doing it with canvas. Measure the width of both. The silk will be wider than the canvas because it doesn't lose as much to the rollover in the fold.