Blazin' Bob, you have the wrong idea about stoning. The stoning is done to the flat back of the ring gear in case there are any high spots from the bolt holes.

You might want to chamfer the id but ever so slightly and I don't believe that will do anything to concentricity.

Keep in mind that every ring and pinion is installed in a machine at the factory and "run in" using an abrasive slurry. So, however the gearset came off the machine is how it's going to run best.

Having a fun Winter?

R.