This unit has lots of photographs that you can zoom in to explore the machine. Has a motor, a threaded rod, and carriage. If it is a Woodrat, it's not the one I've seen.
http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=320996186750&item=320996186750&lgeo=1&vectorid=229466 Begat --
