I don't really like treble bridges that are 24 to 25 mm tall. I want to end up with a bridge height of at least 30 mm at C-88. Yes, this means raising the plate. Start by making the pinblock a bit thicker. Or shim as needed. Don't bother with longer dowels, use an adjustable bolt system of some kind. You can either make your own using cap screws and lock nuts (as I do) or buy one of those currently available. No, I do not alter the rib dimensions to accommodate the taller bridge. It doesn't really matter to me what the original ribs were like--I'm setting up my rib scale and soundboard thickness to match the string scale and am assuming a bridge of reasonable height. Small S&S pianos use relatively low tension scales so the board is going to be relatively thin and the ribbing is going to be on the light side. I do sometimes reset the height of the action but you may find it fits the raised string height just fine. I.e., it was originally set up for a plate setting some higher than it ended up. ddf Delwin D Fandrich Piano Design & Manufacturing Consultant 620 South Tower Avenue Centralia, Washington 98531 USA Phone 360.736.7563 Cell 360.388.6525 Fax 360.736.5239 <mailto:E-maildel at fandrichpiano.com> E-mail 1: del at fandrichpiano.com E-mail 2: <mailto:ddfandrich at gmail.com> ddfandrich at gmail.com _____ From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Will Truitt Sent: March 21, 2009 3:06 PM To: pianotech at ptg.org Subject: [pianotech] Increasing bridge height To the best minds of our generation (at least regarding soundboards): I just pulled a two bridge 1909 Steinway 6' 1" A into the shop for a total soup to nuts rebuild, which will include a new soundboard. I recall some discussion in the past on the forum about increasing the bridge height in Steinways (which some feel is too low) to increase mass and stiffness. David Love and Ron Nossaman's names come to mind. I seem to remember talk of increasing the thickness of the bridge by about 4 mm over the thickness of the original. Since I am putting a new board in this piano and will be setting plate height for global bearing values on adjustable plate bolts as well as setting downbearing on the bridge cap, I am considering the possibility of doing this. I would bore my hammers to make the appropriate accommodations there, as needed My questions are: What are the tonal benefits that you feel are derived by increasing the mass and stiffness of the bridge by increasing the height? Increasing the bridge height will require raising the plate around the rim with the adjustable plate bolts or dowel system to achieve desired bearing values. Are you increasing the thickness of the pinblock by a corresponding amount to raise that end of the plate too? Since the treble bridge is in effect another rib, albeit one running at approximately right angles to the other ribs, are you making any accommodation in the design of the ribs for these changes? Does increasing the plate height require any other accommodations in the action set up other than boring the hammers for the new string height? I find this idea very intriguing. Several years ago I sold a 6' 7" Kimball Viennese Edition grand piano out of my shop for a customer. While not having a particularly elegant tone, it had outstanding volume and sustain throughout, particularly in the treble. What makes this interesting was the fact that the treble bridge heights were 39 to 41 mm. - a pretty tall bridge. Obviously this would not be the only thing that contributed to these tonal qualities, but I cannot help wondering if it were a significant ingredient. I look forward to the thoughts of all contributors. Will Truitt -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://ptg.org/pipermail/pianotech_ptg.org/attachments/20090321/2b29b12e/attachment.html>
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