It is not a rufflerfrom a treadle machine because the distance front to bak is too short. I remember there being a zigZag attachment, but I never touched one. That must be what this is. Just remember to let the machine do the work. Go try it please.

This is my favorite method of turning cording. There are no turning tubes in sewing room. Many different fillers work, like thick yarn or several strands of yarn. Latex gloves would help a lot.