Re: Bösendorfer Rim

[William R. Monroe]

Ooops,

To be clear, these are the percent shrinkage measurements of various species
of woods, measured as a percent of green dimension, from green to oven-dry
moisture content (approx 8% MC).

William R. Monroe



----- Original Message ----- 
From: "William R. Monroe" <pianotech at a440piano.net>
To: "Pianotech List" <pianotech at ptg.org>
Sent: Wednesday, April 19, 2006 8:40 PM
Subject: Re: Bösendorfer Rim


> Avery,
>
> Indeed, to give us some idea of how susceptible various wood species are
to
> shrinking and swelling, the following is useful.  These are the rates of
> shrinkage of various species of wood, in the three dimensions, the
> Tangential (T), Radial (R) and Longitudinal (TR) (from Hoadley's
> "Understanding Wood").
>
> Red Maple        T=8.2    R=4.0    TR=2.0
> Sugar Maple     T=9.9    R=4.8    TR=2.1
> Black Ash          T=7.8    R=5.0    TR=1.6
> White Ash        T=7.8    R=4.9    TR=1.6
> Red Oak            T=8.9    R=4.2    TR=2.1
> White Oak        T=10.5    R=5.6    TR=1.8
> Red Spruce        T=7.8    R=3.8    TR=2.1
> Sitka Spruce        T=7.5    R=4.3    TR=1.7
> Engelmann Spruce    T=7.1    R=3.8    TR=1.9
>
> >From this information (which is indicative of most species) softwoods
tend
> to fare better than hardwoods in respective rates of shrinkage and
swelling.
> In these particular species, the three species of spruce all have more
> modest percentages of swelling/shrinking than any of the hardwoods.  If
you
> are experiencing a greater instability in softwoods, I'd first be curious
if
> the sample was properly dried, rather than some inherent instability of a
> particular species.
>
> Regards,
> William R. Monroe
>
>
> > Any wood will have a change in moisture content with changes in relative
> > humidity. What changes have you observed a spruce rim  making with
changes
> > in relative humidity? Susceptible in what way?
> >
> > Terry Farrell
> >
> > ----- Original Message ----- 
> > > Does the Bösendorfer still have those spruce rims that are SO
> susceptible
> > > to humidity changes?
> > >
> > > Avery
>
>
>
>