Christopher Tidy wrote:

David Billington wrote:

It would be interesting to know what granite was used for the base of
your height gauge. The black granite I have about shows no magnetic
attraction at all when NiFeBn magnet is placed on it. As granite is
predominantly SiO2 it would be interesting to know why the magnetic
attraction.


Given the strength of these magnets I could believe it was just being
attracted to a steel fitting in the centre of the height gauge base. Is
this possible, or was it definitely being attracted to the granite?

Chris

Around here (east Clackamas County, Oregon) you can wander around with a
magnet and pick up gravel.

Iron's a pretty common element, which has a lot to do with why steel is
so cheap.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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