Do NOT leave a key in a lathe chuck any longer than you need it to be there for adjusting the chuck jaws. It is one of the most basic of shop safety rules, and keys left in lathe chucks have caused some horrendous accidents with serious injuries. It is why new lathe chuck keys are furnished as "safety keys", having a coil spring to prevent the key being left in the chuck as is the case in your photo. Someone built a rack on the headstock for the chuck keys, and that is where the key belongs- NOT sticking up out of the chuck of the lathe, even for a photo.
The lathe shows some similarities to the South Bend design. A more modern and heavier apron and tailstock, and the headstock appears to have oil cellars while using split bearings- the oil cups, while in approximately the same locations as on a Southbend lathe, are offset. The lathe looks like a huskier version of a South Bend lathe. Bamford-Chase is a relatively rare manufacturer. The foundry may well go unknown at this point in time. I'd suggest you find some kind of business directory or industrial organization's directory dating to the 40's , I know there was an association for foundries, and the ASME industrial/product catalogs from the 40's may shed some light as well. Even a phone book (if the "Yellow Pages" existed in the 40's) for Portland, Oregon might have listing for iron foundries and solve the mystery.
The man I would have asked, Mr. Robert Yancey, a machine tool builder/dealer in Portland died a few years ago. Mr Yancey was working in Bremerton Naval Shipyard during WWII and started a machine shop and began building custom machine tools in Portland, Oregon in the '50's. Mr. Yancey was a wealth of information and knew machine tools, machine tool builders, and was an amazing man and fine gentleman in every sense of the word. People of his generation who were in the machine tool industry in any locality are getting scarce due to aging out.
