I usually have been hanging out at the Victorian Sweat Shop since it was opened up in January. I love old Singer 15s and I have 2 real old ones and several newer from differed decades. The really old ones have sort of a triangle shaped tension and just a knob on the stitch length. The newer 15s have round tension and big round place with reverse and numbers for the stitch length. I bought an old one and as soon as I can I will be doing a photo shoot of the differences over at VSS. Some times they can be a bear to clean up and there are posts at VSS about that.