John Tuttle Wrote:

> I was always under the impression that the pistons were made of a
> carbon compound.  The book calls the substance Delrin.  ... And the
> contact bar was supposedly coated with gold for long life and minimum
> corrosion.

I stand corrected.  The pistons were sort of soft like rubber.  Delrin
can be very similar in texture.  It is a plastic/Nylon type substance
that we have been using for harpsichord plectra for 30 years or more.

The gold was there, but as I remember they were worn through the gold
plating and still needed cleaning.  Use a pencil eraser for such
cleaning of gold contacts like you do your computer contacts which are
also gold.

D. L. Bullock     Piano World   St. Louis