When SITD is what the quilt really needs and I can't think of a way to avoid it, the ruler helps. With the stitch regulator on I can sew a few stitches, guiding the machine with one hand and the ruler wth the other. Move the ruler forward and do a few more stitches. Laborious. The ruler holds the seam open and the foot of the machine from wandering off the ditch. LONGARM ONLY. There's much easier ways to do SITD on a domestic machine.