Martin Sigley writes [ref. 060612 MMDigest]:

> Purchase two 4-ft. (for a full set of 88) half-inch thick
> pieces of maple from your local hardwood store.

Maple should not be used for pneumatic boards, the reason being that
this wood is much harder than the deck board that the pneumatics are
glued to.  This means that when the next rebuilder removes the boards
to recover the pneumatics, the deck boards will splinter and rip apart
rather than the replaceable pneumatics.

There are exceptions to this such, as the Gulbransen action.  But if
you choose to replace the wood for the key pneumatics, please use poplar.

Pete Knobloch