Hi All,  I was reading what Mike Knudsen said about the tone rods in a
Chein PianoLodeon.  I had a flashback to when I used to work with a guy
who collected pieces of metal that would ring, when they were struck.

One day he asked me why I thought some pieces of metal would ring
better than others.  I told him my father was a toolmaker and that
my father told me you can tell if a piece metal is tempered because
it will ring longer and clearer than the same type of metal that is
not tempered.

The bar stock found in hardware stores comes cold-rolled; in this state
the metal can be cut very easily.  In order to temper it you must heat
it up until it is cherry red, then drop it into water or oil.  To
un-temper metal heat it 'till it is cherry red and let it cool slowly.

A piece of metal should only be tempered and un-tempered a few times.
I believe the carbon in the steel becomes unstable and the metal
develops cracks.

John Conrad Kleinbauer