Make a soundboard--Measurements

[Farrell]

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That's exactly what I have done as wel Dave. Approach also from Del. =
Works great. That way also, when rescaling, you are not restricted by =
the original speaking lengths and bridge shape.

Terry Farrell
  ----- Original Message -----=20
  From: David Love=20
  To: Pianotech=20
  Sent: Friday, October 24, 2003 6:26 PM
  Subject: RE: Make a soundboard--Measurements


  The bridge I just did I ended up laying out from scratch rather than =
trying to follow a pattern, an idea I got from Del Fandrich.   I found =
this to be easier and more accurate since I was rescaling and making =
slight alterations to the speaking lengths.  It also allows you to avoid =
duplicating mistakes on the previous layout.  The method I used was to =
first mark on the plate the center string locations on each hitch pin.  =
I used a dummy tuning pin with a string attached (Mazzaglia) which I put =
into the center tuning pin hole on the plate and wrapped the string =
around the corresponding hitch pin.   Eyeball the string in a straight =
line through the capo (or from the agraffe) and over the bridge and make =
a pencil mark right under the string on the front and back of the =
bridge.  Take a small straightedge and draw a line, move to the next =
one.  When you are done look at the overall spacing and make any co! =
rrections to get it looking even.  From there measure your speaking =
lengths and mark on the line the front center pin location.  Using one =
of several three hole punches I also got from Mazzaglia (depending on =
spacing), mark you pin locations.  Measure from the front row to the =
back row at whatever pin spacing you are using and mark the back row =
center pin.  Using the three hole punch, mark the back row.  At that =
point, if you are going to paint graphite on the bridge to, do it then, =
it makes it much easier to see where you are notching if your eyes =
aren't as sharp as they once were, like mine.  Drill your bridge pin =
holes.  Then mark the side of the notch at 90+ degrees (whatever you =
use, I use 93) off the front pin line.  I use a small piece of mylar cut =
at the proper angles which a lay along the pin line.  Look over your =
markings to see that they are evenly spaced.  Cut along the line with a =
small saw to unif! orm depth (don't overshoot the hole, use a chisel for =
that last bit).  Then cut your notches. =20

  I've gone beyond my point a bit, but I found that laying out the =
bridge from scratch eliminated worrying about how precise the pattern =
was and trying to copy it.  I still make the pattern because it gives me =
the location for screws in the top of the bridge when I am gluing down =
the new cap (on an old board), and lets me know generally where I should =
cut my bearing points, and out of habit.  But laying out new gave me =
better results and it may even have been faster. =20

  David Love
  davidlovepianos@earthlink.net


    ----- Original Message -----=20
    From:=20
    To: pianotech@ptg.org
    Sent: 10/24/2003 8:37:18 AM=20
    Subject: Make a soundboard--Measurements


    In a message dated 10/23/2003 11:19:33 AM Pacific Daylight Time, =
michael@gambles.fsnet.co.uk writes:
      Hello RicB
      It would be very important to set down the criteria for =
measurement of
      soundboards. That must be the starting point. If everyone who =
wants to
      partake in this research takes all the stipulated points for =
measurements
      then there might be some realistic steps taken. Be sure to make =
the names of
      these points international!..;-)
      Regards
      Michael G (UK)
      -----=20
         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.=20
      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.=20
       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.=20
      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
     =20

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