I bought a 1/4 "foot which has an guide at the edge of the foot which you lineup with the edge of the fabric, this keeps the needle exactly 1/4 " from the edge and produces an accurate 1/4" seam. The guide us like a piece of metal that runs along the edge of the fabric, I find it very accurate as opposed to lining up with a line on my machine even when piecing 1 1/2 half square triangles