Doug, I have very successfully used wood saw material for clips on a run of bren gun carrier drivers tool box clips I made a few years ago. I cut the blade on a Guillotine for the shape as they were rectangle pieces. I was able to drill holes in it to rivet it to the doors. I tried to find the thread I did a few years back but couldn't find it. I did use the oxy/act to get some sharp bends and that worked well but you have to bend it slow as not to snap it.
David, there is 220 3/4 ball bearings in each race so it should spin very easy and I don't think I will have a problem at all with wear. the profile also has a small groove in the bottom and top of the bed which I assume is for grease and foreign material to sit. I cant really bolt it all as there is not enough room as you will see when I get a bit further along. The heat wont be too much of an issue although I think it will be about 3-4 layers in total but once I grind them all it should look like a cast ring and this is also new ground for me as I've not done a ball race before. I will keep posting