I for the life of me can not find the thread now, but someone ( Thayerags, or Rodney stick in my mind ) asked about a machine that a friend sent them a picture of.... said it was vaguely singer "ish" and was an industrial, the continued to ask if any one knew of any machines that we not Singers ( possibly bernina ) that looked similar to the old school industrial's......this is not a Bernina but I have often seen parts advertised for Bernina Husky Viking and pfaff ... leading me to believe there is some cross over...
any way this is a link to an old school Pfaff industrial that could be mistaken for a Singer 31 series ( at least I think so )
http://www.ebay.com/itm/PFAFF-34-6-2...item19e5bc56c3
no idea if this is what you were looking for
Dan