Ebony bridge caps

[Michael Spreeman]

Ron, here is link about boxwood:
 
http://home.att.net/~ShipModelFAQ/ResaearchNotes/smf-RN-Boxwood.html
 
Also, someone here in the PHX chapter told me you have a wicked bridge notching machine.  If you have time, I would really value your input about machine notching. Feel free to take the conversation off list if you prefer and contact me at michael at spreemanpianoinnovations.com.  Thanks!
 
I think you're all right about why the more dense materials were and are used in the high treble.  The more dense the material, generally speaking, the faster the high frequencies will travel through it, minimizing energy loss, and, it has greater mass loading.  I suppose taking this theory to the extreme, we would have steel bridge caps; but a happy middle ground needs to be found for the type of sound you are after.  A very simple experiment is to take several pieces of equally dimensioned hardwoods, place a tuning fork on one end and listen with a mechanics stethoscope at the other end.  Not real scientific, but gives one an idea.  Harold Conklin Jr. performed "real" scientific experiments with this during his years at Baldwin with expensive sound generating gadgets and all of the high tech "listening" and recording gizmos available at the time.   I don't recall if he told me whether any of his findings are published, but I know he has it all documented.  
 
Many manufacturers stopped using boxwood because of cost and availability.  I recently purchased a boxwood log which will net me enough material for about 4 pianos and it was over $200.00, and was the only log I could find.
 
A downside to solid ebony and solid boxwood caps is cracking.  Laminating either material, or a combination of materials makes sense to help inhibit this. 
 
The next obvious question is , why use wood at all, why not use some razma-tazmy high tech composite material that would never change dimensionally or crack?  Like many of the "new" ideas we get about improvements and brilliant new ideas for changing piano design, there isn't much new under the sun.  The most common scenario for me is get this great new idea, spend lost of time developing and implimenting it, only to find out that it was in a piano built built in 1889.  Many materials, various woods and composites, have been experimented with in regards to boards and bridges.  
                Michael C. Spreeman http://www.spreemanpianoinnovations.com

> From: davidlovepianos at comcast.net> To: pianotech at ptg.org> Subject: RE: Ebony bridge caps> Date: Mon, 4 Jun 2007 19:46:07 -0700> > Moreover, I guess I should ask: If boxwood caps are acoustically superior,> why would anyone settle for maple, maple laminated (or reconstituted) or> anything else for that matter? My experience with replacing boxwood caps> with epoxy hardened or laminated caps has not demonstrated any noticeable> drop-off in tone quality. But, subtle (and sometimes not so subtle) things> have certainly gotten by me before so--inquiring minds want to know, what's> the real story?> > David Love> davidlovepianos at comcast.net > www.davidlovepianos.com> > -----Original Message-----> From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf> Of David Love> Sent: Monday, June 04, 2007 5:58 PM> To: 'Pianotech List'> Subject: RE: Ebony bridge caps> > The mass loading that I've seen, or been party to, seems to be much more> substantial than would result from the differences in mass between the two> woods. By the time the bridge is notched and considering the generally thin> boxwood caps that I've seen, how much difference could there be. Do> epoxy-laminated maple caps approach the mass of boxwood, i.e., does the> epoxy itself contribute anything substantial or is mass loading with a maple> cap a requirement in your view for reasons stated? > > David Love> davidlovepianos at comcast.net > www.davidlovepianos.com> > -----Original Message-----> From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf> Of Ron Nossaman> Sent: Monday, June 04, 2007 4:56 PM> To: Pianotech List> Subject: Re: Ebony bridge caps> > > > They might have used denser boxwood in the treble to compensate for the> > increased bearing and shorter speaking and backscale lengths which, during> > expansion, would put a greater amount of compression stress on the cap> from> > the strings. > > > > David Love> > > I think it was the sound, but not because Boxwood is harder > and the little vibrations do more magic things somehow. Not > that harder isn't a good idea, but I think it was, and is, > because of the mass. With Boxwood being half again heavier > than Maple, the bridge is effectively more heavily mass loaded > right at the termination point. That will effect clarity and > sustain, as those of us who have mass loaded bridges in the > high treble have seen.> > Incidentally, every wood imaginable has been called boxwood at > one time or another. Anyone got a real name for this stuff?> > Ron N> > > > 
_________________________________________________________________
Play free games, earn tickets, get cool prizes! Join Live Search Club. 
http://club.live.com/home.aspx?icid=CLUB_wlmailtextlink
-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://www.moypiano.com/ptg/pianotech.php/attachments/20070605/c994493c/attachment.html