i like Alex Anderson's comment, ",just use the 1/4" seam allowance on your machines foot and make all the seams with the same allowance, they will be true to each other, but use high quality thread which is finer than regular sewing thread to get a truer 1/4" seam." she is correct, great thread like King Tut (Superior Threads) does make a seam that is more a true 1/4 inch using the "quilt" 1/4" foot on my Pfaff.