I saw Brian Thornton's post about a wood he referred to as 'sweetgum'
used in player actions.  Gum, or American red gum (liquidambar
styraciflua) is also known as redgum or sweetgum.  The last two names
are more specifically used for the heartwood, which is a pinkish-tan
color with occasional darker brown streaks running through it, sometimes
rather highly figured.  The off-white sapwood is marketed as sapgum.

American chestnut was often used as 'secondary wood', that is, as
the middle ply in some bellows/reservoir boards and the lumber core
in piano casework.  Chestnut has an open grain similar to that of oak,
but is a light brown/tan color and much softer than oak.

I've noticed the same rusted-screw problem with mahogany in two early
actions I worked on, and I agree that it's something to do with the
chemical make-up of the wood that causes the rusting.  One action was
a Remington (which I think was made by Starr) and the other was a very
early Ampico installed in a Knabe grand.

John M Runge