This machine looks identical to my mother's 1930 Franklin Delux rotary model 117.851 sold by Sears as part of the Kenmore line. The stitch regulator, tensioner, and bobbin winder are all identical. There are other very similar machines,the White rotary 77 and the Domestic 153. When I was looking for Singer parts, I found several web sites that alsohad parts for the White manufactured machines. There are older manuals on the web and the one from 1913 showsindex number 744 in the parts diagram as the bobbin. The bobbins are an inch in diameter and 11/32 of an inch thick.For extra feet, you need the White style with the horizontal slot in the top that is held by the knurled knob. Singer,Brother or Pfaff feet will not work. There are ruffler and button-hole attachments available for it. Also hemmer feet andan adjustable zipper foot. The easiest way to thread it is to put the spool on with your right hand, take the thread in your left and go thru the slot in the upper thread guide, down to loop around the tensioner, back up the the slot thatleads to the hole in the take-up arm and back to the needle. It can be done in one continuous motion with a little practice.I learned to sew on this type of machine, and it survived that experience and is still going strong. It feeds heavy cloth very well and is very forgiving on upper thread tension.