my own Soundboard

[Erwinspiano@AOL.COM]

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  Terry, Gregg 

       What I was trying to communicate and apparently not very well, was 
that  tongue and groove joints (and finger joints) are ever so much stronger 
than butt joints because mechanically they have more glue surface and they 
interlock. The problem with finger joints in soundboard panel joinery would 
not exist IF WE DIDN'T THIN THEM AROUND THE PERIMETER. In diaphramizing it is 
common to thin the board all the way around the panel which would cut thru 
the finger joints at different levels creating a visual nightmare. With the 
small tongue and groove it is possible to locate them closer to the bottom of 
the panel thereby still allowing for thinning from the top, without going 
thru the joint. Many times panels are thinned to as much as .250 especially 
in the tail regions for increased flexibility.
   To answer Greg's question on machining long straight lines in boards I'll 
answer it with a question how would you do it? And what expensive machinery 
are you prepared to purchase to make one panel a year or two or whatever? 
Unless your relatives have a commercial woodshop buying pre-made blanks is 
way more efficient but maybe not as much fun. My point was making straight 
lines in any kind of earthly material is a challenge and I'd rather see you 
spend your time with the more salient points of sound board making and make 
music, some money and have some fun and personal satisfaction at the same 
time. Know what I mean?
    
 Best--Dale Erwin


.Terry writes> 
> 
> I taking a long shot here, but - I think finger joints are only appropriate 
> at end grain joints. That way the long direction of the grain goes into the 
> fingers and all is strong. If you finger joint perpendicular to the grain, 
> you have little fingers whose edges cut across that grain and the fingers 
> have no strength. My suspicion is that a finger joint used to glue up 
> planks of spruce for a soundboard would have no significant strength 
> increase over a straight, flat-cut joint. A finger joint may be a good 
> thing if good spruce gets so scarce that our four or six-inch wide planks 
> are not available in five-foot lengths!
>  
> Terry Farrell
>   
> 
> >> ----- Original Message ----- 
>> From: <A HREF="mailto:Erwinspiano@AOL.COM">Erwinspiano@AOL.COM</A> 
>> To: <A HREF="mailto:pianotech@ptg.org">pianotech@ptg.org</A> 
>> Sent: Sunday, January 13, 2002 11:23 AM
>> Subject: Re: my own Soundboard
>> 
>> 
>> In a message dated 1/12/2002 9:52:03 PM Pacific Standard Time, <A HREF="mailto:gnewell@ameritech.net">
>> gnewell@ameritech.net</A> writes:
>> 
>> 
>>       Gregg writes
>> >>> . 
>>>     I thought that tongue and groove might be a good idea long before I 
>>> heard about it here. Lately I've been day dreaming about finger joints. 
>>> Any feelings on how that might work in a soundboard situation? It seems 
>>> that a finger joint would offer more surface area than a tongue and 
>>> groove. Call me a ponderer. 
>>>     I would love to here from 
>> 
>>             Greg -Finger joints will not work. Even the tongue and groove 
>> joints must be positioned towards the bottom side of the panel so that 
>> they are not exposed while diaphramizing. 
>>         If you've not ever tried to make a straight line over large 
>> lengths of wood then I must tell you how difficult it is even for the best 
>> woodworkers.
>>       Dale
> 


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