CD What? How interesting! You are right of course, but I thought all 306's took a cam? I googled the 306, and looked at Sandman Collectibles site on identifying Singer models. He mentions the cam knob as an indicater that you have a 306? Geeze, is this 306 just missing the parts to attach the cams, or did it never have the capability to use cams? CD can you explain? I always thought the letter behind the model number merely told where the machine was made? In this case does the 'm' mean a 306 without the ability to use cams? Geeze, I have a 306w, and it takes the flat cams!
Nancy