Mine is a 315.27990 and looks great, with broken internal parts. When I fished it out of the metal dump, another guy there said mine looks like about 1962 or thereabouts. Go to http://www.oldwwmachines.com and download scanned Sears Craftsman catalogs from the 1950s and 1960s. You might see it there. It was made by Ryobi I believe. Again, check old wwmachines.com and look for Craftsman OEM numbers for the original manufacturer.