Thanks for the compliments Cannoneer, little seacoast, and JeffG. John, I used rock maple for everything except the 1/4 scale naves which are white oak, which, at the time, I thought was all I had thick enough to make the naves, later I found a chunk of black walnut that I could have used.
Douglas, I worked on those wheels off and on for several weeks and built the jigs and fixtures as I went along so I do not have a good feel for how long it would take to build a wheel straight through from start to finish, maybe a minimum of two days with all equipment in place and operational. Cost? Material cost will run $40+ per wheel or more according to type of wood used - should use quality wood. Since I don't make things for sale I don't have a feel for how much a wheel would cost. I'm pretty sure that they would cost more than most people would be willing to pay. Small scale doesn't necessarily mean easier, quicker or cheaper. Oh, by the way, thanks for the Kewpie, I like that picture too.
Zulu, Pictures 6 and 7 show the shop built tenon cutter in operation. I had to make the cutter since commercial tenon cutters are not available below 3/8 inch. Two opposing tenons are first cut to the exact radius of the inside of the felloes, then the drill press depth stop is locked then the rest of the tenons are cut in turn. The nave bands are pressed on. The tires were heated to a point that I could still handle them with gloves then installed. I made the tires 1/16 inch smaller than the wheel.
The pictures are not meant to show how wheels are made, but to show how I made them. There are several ways to do each step so go give it a try.