Soundboard Clamping for Downbearing

[Farrell]

Wonderful, wonderful. Thank you Dale. This sounds like a system that I can work with.

Terry Farrell
  
Dale wrote:
>            Well, it certainly is way easier to do the bridge notching / 
> pinning, etc., out of the piano. 
>   So I do the dry fit set up this way. In my climate I like the board to have 
> taken up some moisture but something like it would experience with the R. H.  
> about 40% or EMC about as you said 9% or so. I locate and temporarily install 
> my bridge to the board with soundboard buttons and screws, one between each 
> rib and one through only the ribs in the low tenor that have the feet thing 
> and cutout between them. Usually that's only 2 or three. I Install the board 
> dry by drilling holes for dry wall screws thru the board and into the rim 
> where the acoustic dowels were located. No magic here. These holes will 
> eventually disappear when the holes for acoustic dowels are drilled or fill 
> them with hammer shank if a different support system is used.
>   Next install your plate with the nose bolts for support. Install about 8 or 
> 10 screws in the pinblock, usually next to each strut. I set the plate so its 
> elevation at the last bass end bolt hole is where it was originally which 
> means the plate boss is fairly close to the board. I have a shim between the 
> boss and the board. I put a clamp and block holding down the plate to prevent 
> it from coming up in the bearing procedure.
>     I then turn up my nosebolts which were installed low. This includes the 
> bass strut nose bolt and cap nut too. I pre-stress the board with a shim at 
> each plate strut to simulate some string load as I've described before. I Cut 
> my bearing notches to determine where the bridge height will be. Pull the 
> plate & board plane the top of the bridge reinstall check and make final 
> corrections to height and bridge slope. Pull it out remove the bridge, drill, 
> notch & pin and the other details.
>     After the board is glued in I always recheck my bearing and adjust my 
> plate a bit if needed. This is a great method but you'll find your board ever 
> much stiffer when you go thru the pre-stress bearing check at this point 
> because the bridge and board have been glued on and everything has gotten 
> stiffer. Which means your bearing may be more than you bargain for. With this 
> method I've learned to set the distance bearing on the stingy side especially 
> from about note 60 ish on down. With Steinways it's possible to shim aliquots 
> up if too much bearing is attained. Flexing the plate up with the nosebolts 
> is good for about 1/4 turn max. in my book with Steinways and none in Masons 
> as the plates are too stiff to flex.
>        Hope that helps
>         Dale Erwin