What I have is a Craftsman Model 101-07403 lathe that was made by the Atlas Lathe Company. This is a 12x36 inch lathe, meaning that the "swing" is 6 inches allowing 12 inch diameter objects to be turned, and the bed is 36 inches long. According to dates scribed on the races, it was manufactured in 1951. My lathe is serial number 32068 (the number is stamped on the top surface of the ways, right above the right lead screw bearing and support. Just for the record, the date stamped on my left spindle race is 8-14-51, and the date on the right spindle race is 5-10-51.
I was warned about several things even before I bought it. First, I was told that this Atlas lathe was among perhaps the worst lathes I should even consider buying. Second was that the gears and many other parts were made out of a zinc-aluminum alloy called "zamak". I was also told by the same fellow that told me all of these worrisome things that he once made a living as a professional gunsmith using one of these lathes. Also, I considered that the lathe I was looking at is at least 50 years old and still running; so those Zamak gears, though not what one would wish for, were still quite serviceable, and if I treated them gently, would likely serve me just fine if I didn't abuse the lathe.
Note that the dials on the Atlas tell you tool motion. So if you are turning a shaft and want to reduce the diameter by 0.10 inches, you need to move the dials 0.05 inches.
The zamak parts on this lathe receive a lot of abuse, (verbal abuse on forums and such) and perhaps rightly so. On the other hand, the use of zamak serves two purposes. It makes the lathe lighter -- no small thing if you have to move a large lathe. They also make the lathe affordable, certainly at the time of manufacture, and still today. The gears were die cast out of zamak rather than being machined from steel, saving weight and expense.
Craftsman of course doesn't actually make anything, but is just the name Sears slaps on whatever products they arrange to carry in their stores. Atlas bought Clausing in 1950, and around 1969 renamed itself Clausing International. Amazingly Clausing still stocks and sells parts for the Atlas Lathes at their Service Center in Goshen, Indiana. Call them at 1-800-323-0972 or email at email@example.com (I called them at 1-800-535-6553 on 11-17-2011, so the above phone number may be out of date.)
The Spindle bearings can be either Babbit metal (in which case the headstock has bolts with clamps that hold the bearings), or roller bearings (in which case the headstock is a single piece, no clamping bolts. Mine has roller bearings. Mine also has the "quick change gearbox", which is apparently an option, but which should be a great help cutting threads.
There exists a comprehensive 240+ page owners manual for the 12 inch Atlas lathe that includes maintenance and lubrication instructions, "probably the best instruction book ever produced by a lathe manufacturer." There is also a 61 page "supplementary" screwcutting instruction book as well as other documentation. I have had the instruction manual waved under my nose, but still am eager to get my own copy.
Tom's home page / firstname.lastname@example.org