(note: holding stub axle by the splines was an error duly pointed out by David in the comments. Axle re-measured and post updated.)
I was complaining to Phil Z. about my wheel bearing failure and he suggested I have a look at the stub axle. So I chucked it up on the lathe, holding it by the splined outboard end (was careful to have the chuck jaws positioned correctly on the splines) and then I measured a couple of things.
Where the outboard bearing seats had 0.009″ runout.
At the inboard bearing seat I measured 0.015″ runout (sorry, fuzzy pic slipped past me).
Where the seal rides, 0.020″.
The face where the CV joint mates had 0.010″ runout.
I did not measure that outer edge of the CV mounting flange as I thought eccentricity there was not important as the cv is aligned by the bolts.
And here is a quick vid of the assembly spinning.
What does all this mean? How does a new stub axle measure up? Was this runout the cause of my bearing failure?
Addendum: Crow eating time. David’s points about where I was grabbing the axle (splines) was correct. I re-measured runout with axle held by outer bearing seat.
Runout at inner bearing about 0.005″.
At seal, 0.007″.
Flange face, 0.002″.
Looks a lot better in motion.
So there, no smoking gun after all.