[pianotech] Measuring Crown Radius

[Ron Nossaman]

On 7/14/2011 4:52 PM, John Delacour wrote:

> Whether they are or not would surely make quite a bit of difference. If
> the case is not considered (by Steinway's for example) to be involved in
> the process, why do they glue the case to the rim before fitting the
> soundboard, thus causing themselves a lot of tiresome work that could be
> avoided if they glued down the soundboard before attaching the case, as
> many, if not most, makers do?

That's something we've always wondered, as with a number of other things 
"Steinway" that don't make much sense.


> However that may be, the method seems to me inherently unstable. For one
> thing the bars (ribs) will ever afterwards be acting to remove the
> crown, won't they?

Absolutely, which is the simple point I've failed to make to David.


  >If at any time the moisture content of the board
> rises to a point where the board proper is crushed, then the bars will
> be keen to relax and pull down the crown.

Which is exactly what happens.

Ron N