---------------------- multipart/alternative attachment David, and others. This is very interesting for sure, and a few pictures of your work would be even better. But the thread is about listing up a set of criteria for soundboard evalutation that are at least somewhat conducive to describing its overall sound characteristics. Dale Erwin stimulated the idea by asking me to conceptually "make a soundboard" and then <<tell us how it sounds and why>> I think actually this is a great idea from several standpoints, good for general discussion, and good for helping along the understanding of soundboard design for the average tech following along. Refining Dales list of things to measure up and check out seems to be a good way of getting started. Nice post tho btw. I seem to remember an article on this exact method in the journal a few years back. Cheers RicB David Love wrote: > 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. 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. David > Lovedavidlovepianos@earthlink.net > > ----- Original Message ----- > From: > To: pianotech@ptg.org > Sent: 10/24/2003 8:37:18 AM > 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) > ----- > > 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 > -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html http://www.hf.uib.no/grieg/personer/cv_RB.html ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/24/7c/a6/71/attachment.htm ---------------------- multipart/alternative attachment--
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