Gary:
I am in the same situation of having three (3) lathes. Of the three, I use my South Bend 10L more often. The larger hole thru the headstock spindle and a set of 5 C collets is usually the deciding factor. I use my LeBlond 13" for heavier jobs (within the envelope of a light-duty geared head lathe). The third lathe is a South Bend 10K, fully tooled in nice condition which was given to me as it needed a home. I doubt I have used the light 10" (10K) twice in maybe 15 + years. It sits under a cover.
To give an idea of what kind of jobs I run in the LeBlond 13: We had a Cummins diesel engine on an old locomotive which had some coolant in the crankcase. Bad news. Before we assumed the worst cases, I decided to check the oil cooler for a leak. We got the oil cooler off the Cummins engine and over to my shop. My plan was to put an air test on one "side" of the cooler (shell or tube sides) and see if held air pressure. The oil side (shell side) of the cooler was the easiest to blank off. I had a piece of 1/2" A-36 steel plate that was just right for the blanking plate. I laid out and drilled all the bolt holes in the plate, then made a "boss" out of square stock and tapped it for 1/4" pipe threads. I welded the boss to the plate and was deciding how I'd get the sealing surface of the blanking plate flat. I decided the easiest and quickest way was to weld a chunk of 2" round stock to the side of the plate with the pipe connection. This gave me what I call a "spud" or a "chucking boss". The plate dimensions escape me at the moment, but chucked in the LeBlond lathe, the corners of the plate neatly cleared the carriage wings when I pulled the spindle over by hand. I had "burned in" the chucking boss and pipe connection using stick welding (E 6010 & E 7018) and did "quarter the welds" and peen them with the needle scaler to try to minimize the plate curling from the weld stress. I chucked the plate in the LeBlond 13" lathe and with a high speed steel toolbit, took about a 0.030" deep facing cut. It was an interrupted cut, and the plate was large enough that it was near the limit of the lathe's capacity. The LeBlond lathe peeled off 0,030" like nothing using a fairly coarse power feed. To finish the plate, I actually ran a coarse feed to get a "phonograph finish" to "bite into the gasket". The whole job took maybe 20 minutes in the lathe. On the 0.030" cut, the chips were coming off blue and I was slopping on the sulphur/lard cutting oil.
I could not see using good gasket material for this air test, so cut a gasket from the thin cardboard of an empty cat litter box. The gasket was oiled and the bolts made up.
The air test on the cooler was done with a "Christmas Tree" having a couple of needle valves and a pressure gauge. It let me do a leakdown test. While the air was being put into the cooler, I did a soapsuds test of the gasketed joint. It was "bubble tight". The leakdown test showed me the cooler did have some leaky tubes, very small leaks but enough to put coolant into the crankcase when the engine was shut down.
It is jobs like that blanking plate that show what that 13" Roundhead lathe can do. I use the Roundhead Regal lathe for jobs that are either too big to go into the 10L South Bend Lathe, or jobs which require hogging off a lot of metal- something the Southbend lathe is slower at doing. My Regal was built in 1943. Recently, I made some bearing quills out of 3" aluminum bar stock. These had to be bored to accept ball bearings at either end, so things had to be dimensionally accurate as well as concentric. I did the job in the LeBlond Regal lathe. I had no trouble hitting half thousandths for the fits to accept the bearings. I also had no problem maintaining concentricity using a 4 jaw chuck and steady rest. I enjoy using my 13" Roundhead Regal lathe, but I am realistic enough to know it is a light duty engine lathe, and is far from a toolroom machine. At the same time, it is a surprising machine in the work I can do with it.
