rim laminations

[John Delacour]

At 14:32 18/08/01 -0500, Ron Nossaman wrote:
> >   Hi Ron-----I'm sure it is so. If not mahog. it's walnut.-----Best--Dale
> >Erwin
>
>Sons of guns. Thanks John and Dale. Looks like I'll have to pay closer
>attention.

Concerning the material used for inner rim laminations, I wonder how 
critical it  really is tonally.  The inner rim, of course, has several 
functions -- 1) to provide an immovable surround the for the framing (back 
or Rast) into which the braces can be securely dovetailed, 2) to provide a 
solid medium into which the string-plate bolts can be screwed, 3) to add 
rigidity to the outer rim when this is glued on and 4) to provide, at its 
outer edges only, and in combination with the outer rim, a massive and 
solid frame for the soundboard.

For this last function, 'hardness' of the material is probably not 
significant especially as the glue line will increase this, within reason 
(hemlock might make a difference!) but mass might have a tonal effect and 
mahogany, in spite of its 'softness' in comparison to beech or maple is 
actually significantly denser than either.


         Oak          0.625 g/cc
         Beech        0.69 g/cc (much used in Europe rather than maple)
         Maple        0.795 g/cc
         Ash          0.845 g/cc
         Mahogany     0.852 g/cc

(Source: The Timber Merchant's Handbook)

The old Erard grands had both inner and outer rim entirely of horizontal 
laminations of ash, which, besides its good density, is also very suitable 
for walking-sticks and bent rims.  It is the tight structure of beech and 
maple that render them suitable for the uses we put them to rather than 
their actual density.

JD