So the drums from Speedway were .005" out of round (not terrible), and showed .010" run out (bell mouthed). I did turn this drum to .002" out of round, and .001" run out, took .010" out of diameter to do this. The drum still had tight and loose spots, which prompted me to check the concentrically of the hub to the axle center line.
Here the problem was found. One side was .014", and the other was .022" out of round. So how could this be?
Recall that I did machine the axle housings for bearing race repair sleeves.
https://www.fordbarn.com/forum/showthread.php?t=332246
As indicated in my post the housing was centered on the existing bearing race to .0015" to the tool post on the lathe. This was done as the only reliable means to index the part for this machining process. It does not verify it's concentrically with the axle center line, as the hub is still yet another variable in this equation. It is also that the repair sleeves were not perfectly concentric, and also could have been affected by pressing them into place.
I may be splitting hairs here, but what I did was locate the high points of both members (drum and hub), and installed them to cancel one another's offsets. I think that if these checks were made on other machines, the same conclusions would be apparent....Maybe not, but tell me, why is it considered to be normal procedure to sand shoes to fit their drums? This suggest to me this very type of situation as I describe to be the case commonly. Everything is manufactured to acceptable tolerances, they can become cumulative to cause an overall out of specification condition to exist.
