bottom board

[Terry]

Ron N wrote:

(snip)

> I use Baltic Birch plywood and drywall screws.
> You aren't holding screw threads here, you're holding screw heads. The
> threads are in that fine improved-with-age wood in the piano, which isn't
> currently being replaced. No T-nuts required, even if you could figure out
> how to install them.

Agree with perimeter screws. I was referring to screws to hold pedal springs
and pedal mounts. I've seen many of them pull up on pianos - you want
something pretty secure to screw into. Perhaps your birch plywood is solid
enough. Maybe drilling a proper sized pilot hole helps also. I've seen
plywood advertised as such - are the inner plies birch? And are they really
from the Baltic Sea area? Not enough yellow birch trees in Minnesota and
Ontario?

> Stiffness isn't all that critical either, since it's screwed down around
> it's perimeter. Front to back, the span isn't long enough to provide
enough
> flex to be a problem if the bottom board has any stiffness at all. The
flex
> in the toe rail is a more likely source of problems. If the toe rail is
too
> flexible, a bottom board of hardwood planking will help,

Good point.

> but it's easier to brace to the keybed and get around that problem.

Brace the bottom board or toe rail to the keybed? How ya gonna do that? Run
a vertical piece of wood from the middle of the toe rail to the keybed?

> The original
> manufacturer of the piano didn't see the need to make the bottom board
> flood tolerant, and I don't either. For some years now, I've recommended
> that pianos be kept out of water whenever possible.

Smarty pants!   ;-)

Terry Farrell