Of traditional American WW (Webster Whitcombe) design, the 50 mm centre height, 8 mm collet Zimmerman was stamped on the end of its bed: M.R. Zimmerman Mach. Wks. Holsopple, PA. U.S.A.
In the 100 years spanning from the middle of the 19th to the middle of the 20th centuries, many makers of lathes for watchmakers were to appear, though many re-branded to appear by other than their real maker. Hence, although Zimmerman might have been the maker (and the stamping Machine Works would lend credence to this), there is no surviving evidence of their manufacturing capabilities - nor indeed any other horological tools they might have produced. Hence, it is just as likely that they were a supply company that commissioned a batch of lathes from one of the better-known makers. Every Zimmerman found has a number stamped into the end face of the bed; this, instead of indicating a model type, would be a Serial number - the highest so far discovered is "39"
Appearing to be a relatively "beefed-up" lathe in comparison to the 8 mm Peerless/Marshal types, the Zimmerman had a more massive bed and fitments (a comparison photograph is shown below) - perhaps the intention was to offer a watchmakers' lathe capable of heavier-than-usual work while preserving the delicate feel inherent necessary in such a small machine.
If the finish on a Zimmerman is chrome - and it appears to be - this seldom-found lathe would have been made post-1930 - a point at which chrome became widely available as a commercial finish.http://www.lathes.co.uk/watchmaker