Aluminum will clog most stones quite rapidly, and will adhere and cause terrible 
gauling on steel tools. The best tools for aluminum wheels are carbide cutters. 
The sizes can be limited only by your budget, and they continue to cut long 
after a steel tool is hopelessly bound up with adhered aluminum. I used a 5/8" 
round cutter, chucked in my hand-drill, to finish out the work I had done on my 
Audi wheels.� That cutter cost about $15.00. The�metal still stuck to the 
carbide, but would not stay on nearly as stubbornly as on my steel tools.�

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>Ok, got this set of rims from an Audi A6, they fit fine in the back,
>but the fronts need to be opened up a bit to clear the grease cup.
>Took them to a local machine shop and explained to the owner exactly
>what I need done. In the center of the rime is a small raised lip,
>and it need it ground down. No, he says, you have to leave the
>vehicle so we can test fit. I can't-don't-want to leave the van. I
>don't see why I need to except that he is trying to make it a more
>$$$ job. So I head to Depot and get two grinding stones to chuck in
>my drill, plus a bastard file. I'm getting there, but it is slow
>going. Can anyone recommend anything else to grind this lip down? Thanks, Jeff
>
>
>
>Jeff Stewart