Hi Harry

You, I and a lot of others have, or have had this problem, so much so
that Oneway has made the precision balancing system, I find it rather
expensive, but it does a excellent job.

The problem has arisen because the flanges that hold on the wheels are
now stamped out of a steel plate, rather than machined, as was done
before and still for the higher priced machines.

If you are able to machine the flanges or have it done, or have someone
make new ones, the wobble is almost guaranteed to be gone, if there is
uneven weight within the stone itself, (you only notice that by
vibration), you need a balancing system, like the Oneway, it has
machined flanges for 2 wheels and weights, however in order for the
system to slide on your grinders shaft and in your wheel you do need a
stone whit a large hole.
I hope that this helps you, if I have not been clear enough, don't
hesitate to ask for a more or better explanation.

http://homepage.mac.com/l.vanderloo/PhotoAlbum25.html

Have fun and take care
Leo Van Der Loo