Thanks arftist. I don't have any big pieces of aluminum so I will price them out with the bearings and see if I will save enough to give it a try. My gut says it will be worth it if the wheels turn out good.
William, I have a 3/4 I will test with but once I know it is working I will get a 1.5. I am hoping to find a rebuilt one but I think new they are around $200.
Right now I have it all built except the table and the wheels. I did some welding. You can build it without welding but some of it just seemed silly to use bolts when welding was faster and easier. In the bladesmilth forum a lot of guys have built them and been very happy. Every post I saw that completed it said it was as good as their expensive grinders. Did you see his youtube video? Very impressive.
Cost wise I have about $50 into it and had to buy most all the steel from my favorite scrap place that sells drops. I figure $200 for the motor and either $100 or $300 for wheels and misc stuff depending on if I can make the wheels or not. So all in all a great grinder for $400 to $600. A lot better than the $1200+ similar grinders are selling for. And you can build more attachments as you need them. I am just starting out with a flat platen and going from there as the need arises.