Jim Wilkins wrote:
On Sep 7, 7:22 pm, Louis Ohland wrote:
...
I was going to ask the folks at Danaher Motion about doing the centers
at each end. Way more precise than I could do. If they can hold .001 I/m
a happy camper.

If they have good-quality collets 0.001" should be easy. You could
probably center them that well yourself by running the end in a steady
rest and cleaning up a drilled center with a lathe tool. I think the
core of Thompson rod is soft enough.

Apologies, my News ISP is bothering me about too many connections again...

Uh, the purpose of this exercise is to get a decent test bar that does
not depend on me or the lathe being in proper alignment...

The Thompson rod I'm looking at has the hard surface, but "soft" center.
Crunchy on the outside, chewy in the middle. I'll ask the engineers what
they'd recommend for what I'm doing (besides more lithium, that is). I
like their concentricity...