John K Jordan
>>>I'm thinking that the ends are not 90 degrees to the 1" hole...
I agree completely, without square ends you are doomed! Well, have a problem. Yikes, that seemed so obvious I forgot to even consider it. It should be easy for Mark to check one of his existing blanks that didn't work (and probably easy to fix them).
How do you prefer to hold and square up something with a large central hole?
For pepper mills (and anything else with the block initially held in a chuck) I think it's best, of course, to face off the far end of the block before drilling.
Then for a pepper mill I part off (or remove from chuck and bandsaw as square as possible), reverse and hold with the wooden "jam mandrel" in he headstock and support the other end with another wooden mandrel and face off the far end. Wood is perfect for support since I can cut into it a bit when cleaning up the far end, even if I cut a little into the shoulder.
Maybe there is a better way but that's the way I like to do it. I suppose the wooden cone would work on the tailstock end but I haven't tried that. Or use the aluminum cone that comes with many live centers, face off most of the way to the center, then remove the cone and clean up the tiny bit in the center another way.
After the piece is turned round (and assured to be concentric), I wonder if the end could be made square on disk sander?
I'm scheduled to demo work-holding methods in July this year. Maybe holding something like this would be interesting.