I have a 1952, 11" Logan lathe that was originally fitted with a flat belt, stepped spindle pulley. Some years ago I converted it over to a single, 3/8" pitch timing pulley. Although I had a variable speed DC motor powering it, I still had only one ratio between motor and spindle which was fine for higher speeds but not so good for slow turning large objects like flywheels. So, I decided to convert it again, this time to a V-Belt, 4 step pulley. I bought an Atlas spindle pulley off ebay where they seem to be plentiful and relatively cheap. The model number is 10-79, like this one:
http://www.ebay.com/itm/Atlas-10-lathe-Spindle-pulley-with-bushings-10-79-/111589889495?pt=LH_DefaultDomain_0&hash=item19fb4695d7The pulley comes with a 1 3/4" OD bronze bushing inserted in the bore. I pressed this bearing out and was able to enlarge the bore to 1 7/8", the OD of my spindle. This only left about 1/16" of material in the valley of the smallest pulley, but the rest of the pulley is left with about 3/16" meat which is plenty. My lathe has long since had the backgear removed, as well as the bull gear. I was able to turn down the aluminum timing pulley I had made to fit in the opening inside the large end of the Atlas pulley. The slotted aluminum insert fits over a key in the spindle. The cone pulley drives the aluminum insert with two, 3/16" SHCS's, threaded thru two of the holes. The heads rest in the two, round depressions in the Atlas pulley. Here's a couple of pictures of my setup.
Next I have to fabricate a countershaft which will attach to the back of the lathe headstock.
Chuck