Using a surface plate, I've just checked my 12" high height gauge against
gauge blocks, with similar results for different gauge blocks.

What I've noticed is that the machined measurement surface of the height
gauge arm isn't parallel to the surface plate. (It's around 0.010" higher at
the tip as compared to its height at a position 1.5" closer to the column.)
The micrometer has (standard?) 0.0005" increments, so am I right in
expecting something better than this?
If the height gauge column is tilted with reference to the base, would I be
able to check for this by sighting against a precision engineer's square?
(Which I don't have, as yet.)
I can't see any signs of damage to the height gauge - it's an APE Microball
type, and was supplied in its fitted case.

Many thanks for any advice.

--
M Stewart
Milton Keynes, UK
http://www.megalith.freeserve.co.uk/oddimage.htm