On Fri, 09 Jul 2004 12:18:15 -0300, Machineman
wrote:

In manufacturing they use a center hole grinder, lots of different
models available, here is one I found on a search
http://www.machineryvalues.com/xdetails.cfm/QN/126727
Not overly complex, usually a dead center, steady rest and a cone wheel
grinding wheel. But if refurbishing a center in a shop the above
practice is the way to go.

Time for some massive snippage her

The machine shown, I've seen them in Case, is more used in a
production setting, used between heat treating and the final grind
ops. More to take care of any nicks or dings and any possible
distortion that happend in heat treating. (The V block and destaco
clamp sorta give this away.) Beyond that point, concentricity is held
from the center, which for production is probably the only practical
way. I picked up the "steady rest and tool post grinder" method from
watching the machinists regrind centers on some very expensive splined
inspection arbors. These arbors were all made with a stub on the end,
hardened and ground, which I assume was ground to be concentric with
the spline PD and the center from which the spline had been cut.

I would have loved to see how they set up the hobber to make these
arbors, .004" taper over 12" of length, probably some tolerance on the
PD, but almost nothing for helix. I assume there was some grinding of
the spline after HT, but have no idea of how that would have been
done, don't think I want to, either.
Lennie the Lurker