On Mon, 26 Jul 2010 00:36:28 -0500, Ignoramus1880
wrote:

Yes, the spindle is a splined, two part thing and the hollow top of
the spindle stays in place, regardless of the Z axis position (bottom
part).

This means that mounting an encoder on the top is very easy, just a
little machining exercise to make something that I can stick inside
and make it stay connected to the spindle, with some little top piece
to mount encoder wheel.


Correct. Try something that will expand into the top of the spindle.
Its not a "wet" area, so your choice of materials is quite wide.

Gunner

One could not be a successful Leftwinger without realizing that,
in contrast to the popular conception supported by newspapers
and mothers of Leftwingers, a goodly number of Leftwingers are
not only narrow-minded and dull, but also just stupid.
Gunner Asch