Of course, that there were some cheaply made older lathes in the past before the woodturning revolution with it's multiple facets and wide popularity. However when labor & materials were cheaper, the major manufacturers at the time seemed to over build their better quality smaller swing lathes. These lathes were essentially for turning spindles (not much large face work being done then), but they were made of fine grained quality cast iron with rugged bearings, castings and decent machining, yet often limited to a 6" throw and less than that at the tool rest.
There are a lot of these fine old timers around and reasonably priced at that. I suppose they could be easily and safely converted to a much larger swing and many have been, either outboard or inboard with raising blocks. I realize that how much larger the swing allowed depends on the lathe and its supports, the timber, the balance of the blank, the turner's ablility, the grimness of his facial expression and the decibels of his grunting and swearing.
What can you do to improve on the old machine's specs. for larger face turning? Are there any rules of thumb or warning signs and symptoms that you use to predict a particular face turning you can safely swing or for that matter that you've gone too far? (ie. before the catastrophe) :)
Turn to Safety, Arch Fortiter