The belt-drive setup for the power feed calls for a 4"-1"
reduction pulley. I couldn't find any easily, so I started with one of these...
...and machined the hub into a 1" pulley on the lathe!
Since it's an idler pulley, the set screw is not needed, except to hold it on the arbor while machining the hub. I took out the screw, ground it down to about 1/8" long to keep from hitting it while turning the hub, and put it back long enough to machine the 1" pulley.
It was a little hairy, because I couldn't figure out any way to get the
tool post close to the pulley hub without running the compound-feed into the 4"
section of the pulley. I ended up just sticking the cutter out as far as it would
go, and was _just_ able to reach far enough. I did the initial cuts with left-hand
and right-hand cutters, and finished up with a round-nosed cutter. I also shortened
the side-walls of the 4" section, since there's not a lot of extra space between the
pulleys, and only a small lip is needed to keep the round belts in place. I gave the
whole thing a little buffing with a strip of 120 grit emery cloth to get rid of any burrs
that might cut up the belts.