Compression ridges was :Do you dry the ribs, along with the board, prior to gluing ?

[Dean May]

Greg-
>>I had not heard Del's assertion from your first sentence before.

What I particularly remember from what Del said was the inverse
mass/stiffness relationships between the treble and bass sections. Perhaps
he could chime in here if he is on the list and clarify. 

>>Regarding your last statement do I understand that you wish to tie
the high treble bridge into the case? 

My idea was not to tie the bridge into the rim, but the rib below. Instead
of having the final treble rib running transverse to the bridge and grain,
have it run along the bottom of the final segment of the treble bridge,
starting at what would have been the next to last rib and proceeding to the
rim underneath the bridge. I would want to try it with that new rib tied
into the rim and also try it with the rib not tied into the rim- just for
fun. 

>>If stiffening the high treble is something to
be avoided then what exactly does the treble fish provide?

It reduces the diaphragm area (think tweeter) and adds mass to the system.


Dean

Dean May             cell 812.239.3359 

PianoRebuilders.com   812.235.5272 

Terre Haute IN  47802

 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Greg Newell
Sent: Friday, February 01, 2008 9:38 PM
To: 'Pianotech List'
Subject: RE: Compression ridges was :Do you dry the ribs, along with the
board,prior to gluing ?

Dean,
	I had not heard Del's assertion from your first sentence before.
That is very interesting. Why wouldn't the greater flexibility in the high
treble also absorb the energy being transmitted there? If Flexibility is NOT
desired in the bass then it would seem that Thump may have a point about the
usefulness of an old panel, yet I still wouldn't trust it in a CC rebuild. 
	Regarding your last statement do I understand that you wish to tie
the high treble bridge into the case? How would that help? If stiffening the
high treble is something that you wish to avoid it would seem that this
would do that quite handily. If stiffening the high treble is something to
be avoided then what exactly does the treble fish provide?

Greg Newell
Greg's Piano Forté
www.gregspianoforte.com
216-226-3791 (office)
216-470-8634 (mobile)