i respectfully disagree w/  the premise that the wheel must fit snugly
around any part of the hub.  the lug nuts/wheel bolts fit into
connical surfaces on the wheels so that the wheel is centered on the
hub when the bolts/lugs are correctly tightened.  the wheel to hub
mating surface is not intended to load bearing at the wheel center
area.  the load bearing part of the wheel to hub connection is two
fold: first,  the tension of the lug/bolt and second,  the mating
surface formed by the flat section of the wheel and the adjacent flat
part of the hub where the studs are or where the wheel bolts thread.
the reason some cars require that you pound a wheel off of the hub or
brake drum is that rust builds up and locks the wheel to the hub or
drum.  the vast majority of cars have enough clearance between the
wheel center and the hub center grease cab or axle end that you can
lift the wheel onto the projection,  fiddle w/  the bolts and then
when you tighten up there is plenty of room between the hub center and
wheel center.   the lugs/bolts do carry the load.  old beetle/microbus
wheels had a vast opening in the center.    sorry for being long
winded but the only danger in machining the wheel center is in
compromising the wheel's structural integrity.

cheers
jim catterson
91 syncro
93 ev gl                  ny

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