They are not featherweights because these machines are hinged to the cabinets. The cabinets for the featherweights came out some time in the 50's I do not remember exactly when because Mr Parsons made the first cabinet for the featherweight after the Singer rep. told him that it could not be done. A box was made to fit the bottom of the featherweight machine and then the box fit into the cabinet. I know it was done because I was there. Later on Mr P. somewhat modifed the cabinet for better fitting but I no remember exactly how.