I'm not sure I understand the question. Any machine can sew a scant 1/4". There's no magic machine or foot that can determine just what the setting should be for your fabric and thread. On my Bernina I know that with the fabrics and thread that I usually sew with, I can use my 1/4" foot and move the needle to the right one click. On my vintage 301, I put tape on the machine bed to tell me where to align the fabric. The amount of "scantness" needed varies for different fabrics and threads.