[STSS]

He is not saying the hammer is anything like the ball in the TEST. The test never came up. He is saying that you will change the hardness of the bearing race with the blows to the studs. The high force impact, and the small contact area (point contact in theory) between the balls and the races will cause you to cold work the metal in the bearings, thus raising the BRINELL HARDNESS of the material. Not a good thing.

Sometimes the thing you are hitting with the BFH is not the only thing you have to worry about damaging. Pulling the bearing and pressing the studs out would be a much "safer" idea. Depending on miles on the bearing, I would probably just pull it and install a new bearing, which comes with new studs.