I can sew a accurate 1/4 inch on any straight stitch machine. I have to jerry rig a ZZ with a wide hole a little, but it is immaterial when doing HSTs as I use the method where you sew two squares through the center diagonally, then cut them. That's why I like two machines set up. The 301 is set for 1/4" and the 15 for anything else. The 15 gets switched out for the Elna if any apparel sewing comes on the scene. Right now the 301 is FMQ so I need the 15 to do all other quilting (piecing).