Make a soundboard--Measurements

[Erwinspiano@aol.com]

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        More stuff to add to your list
          I'm not sure where we left off but I think we were into taking out 
the old board. Glenn ,you posted about the way cool inflater things. Send me 
some ehh?. ANy way we'll assumne the board is now out.
  Now the next few jobs are to keep the board and all it's pieces together 
for reference. The next step is to thoroughly clean the rim joint. I sharp 
chisel will remove the drift wood left on the rim by the board. Take care to avoid 
digging into the rim. If you've drilled the dowells too deep then they need to 
be filled with something I use  a, well ,...more dowell in those cases where 
the dowell driller went to far.  Its wood & it's an easy patch.
      We then use vinegar and water 50/50 and soak the rim joint then 
applyDamp/wet strips of terry cloth  over this on the rim & a hot iron is applied. 
Then as  the glue loosens, use flat scrapers and chisels to extricate the gooey 
sludge as you go. You may have to go round twice on this but a clean joint is 
critical. Use chisels and more soaking to get at the notches. A heat gun can 
also be used to fry the soft glue & then easily scrape  off the ash.
  When every thing is clean it's time to lay out you rib stock. On smaller 
pianos I typically use tight grain sugar pine in the bottom end and white or 
sitka spruce along the belly rail. I've tried a variety of configurations. 
     I'm not going to attempt to tell you how to dimension your ribs claiming 
I have some magic formula or superior method.  I don't. But in general I'm 
making the ribs a bit narrower and a bit taller& crowning them.  I lay out the 
ribs across the top of the case and over the rib notch,then mark the rib on the 
under side next to the rim. I cut all the ribs to fit the case for length & 
then cut the width on the table saw slightly wider than my final dimension. I 
then run them thru the planer to smooth up the sides & remove the saw marks. 
Way less sanding later.
 Now it's time to cut the radius but it'll have to wait.. I was on jury duty 
2 days Its' time for R&R.
  Please add comments ,additions & alterations
   Dale Erwin



 Michael, Ric Glenn

Well, Michael, I don't know if you'd call it research. List you proposed on 
measuring things & observations are really probably already outlined in the 
journal & are just some of the measurements all soundboard installers use. 
  I.E. Measuring string heights, Plate height, bass & treble 88, mark the 
front corner of the plate & measure the distance fore & aft in mm to the case 
side. These locate the plate. Note any odd things about the bridges. I.E. 
inadequate side bearings, strings not going straight to the hitch pins, funky 
notching angels you don't wish to duplicate. Measure down to the top of the plate at 
the bosses. This allows you to set the height of you dowels later if you use 
them.
  Measure the string scale. If funky after unstringing measure string lengths 
& crunch the no.s. Often note 88 is too short for decent tensions in the last 
section. You may want to move the bridge as on many older 1800s S&S grands.
   Note the angle of the bridge top to the board. I don't often do this but 
every piece of info can be helpful.
   (Observation)Look at the thickness of the board thru the action cavity at 
the belly rail & see how it tapers. (Mental note)
  Observation) Any crown left any bearing left. Does the bearing string still 
touch the bridge now the strings are removed. is the bridge below the string 
plane?
  Pull the plate. Pull the bridge pins. make a GOOD pattern noting hole side 
notch cut. Use a bridge pin bit drilled straight down thru the bridge to 
locate the mylar pattern. Place mylar (I use 10 mil) over bridge and tap no. 6 pin 
thru mylar. It make a cleaner hole than drilling thru it.
  I always measure at least first and last string lengths on the long bridge 
& bass bridge. 
   Very important: Bridge location markers.
   I do this 2 ways. I drill straight down. straight is very important thru 
the top of the bridge at not 88 with a 3/16 bit and thru the board & into the 
belly rail. This will help locate the top of the bridge very precisely. I also 
do the same in the tenor end, drilling into a beam if possible. I also take 
direct measurements with a metric ruler to the side of the case at each end of 
each bridge. 
  I also measure the distance from the no. 88  bridge pin hole to the side of 
the case & stretcher. This eliminates the possibility of getting pattern 
located  wrong. There are other ways. Rebuilders please chime in.
   Drill out dowels remove treble cap screws. Now the fun part. It's time to 
knock the board out
   Any body tired yet? More later. going to work
  Later--Dale
  

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