Cool looking machine. I bet it still works as good now as it did back then. It's even got a line for putting coolant or cutting oil on the work. That's neat.
Look for patent number(s). Usually the highest number will get you with 5-10 years of the date of manufacture. My first guess would be 1930s. Google would be your best source of info on that. Engine rebuilder shops may have some info. I doubt you'd find a manual on it. But the "old guy" in a shop may be able to tell you something about it.
Luke M
(resident "old guy")
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.