I'm not convinced that that area was bright and shiny on the spindle when new. I suspect it's an area where the forging was only big enough for the machining to take off the top of the bumps, leaving the bottom of the bumps as-forged. In service that area is usually covered with grease.
R.
Hmmm....never thought of that. I was wondering how it could have gotten rusty in the first place, since it should been covered in grease.
