Second, Norton
wheels are said to be good. We don't have them here (without searching),
but their surface grinding wheels are good, so they know what they do.

I have numerous Norton surface grinding wheels and they run well.
But I am not impress with their bench grinder wheels. I bought
some 10 inchs ones from MSC and they are thicker on one side than
the other and still do not run well after a lot of dressing with a diamond.

Therefore I assume that the wheels are made to differnet specs and
probably by different manufacturing plants too.

chuck