Hello, I just joined this group as member number 1,000 - I hope that is auspicious!
PROBLEM: I own a family heirloom Weber grand, circa 1870s, with cracks in two of the treble struts. Multiple experts have told me the piano is a lost cause. Several luthiers are interested in the soundboard and Brazilian rosewood lid. Last month I was in the process of loosening the strings to begin demolition of the piano when a friend suggested I contact a local metalworker, who then put me in touch with an engineer who does 3D scanning and parts design. This fellow was very interested in the problem and spent an hour brainstorming with me piano-side. He explained that 3D scanning has evolved a lot in the past few years, allowing for very precise design and fabrication.
PROPOSAL: The engineer proposed steel braces that would fit atop the broken struts. How to attach them is a question - he suggested removing the nut and screwing that back over a specially-designed section that would be thinner than the rest of the brace, since there is probably not much extra thread AND I know overtightening can be disastrous; the ends also need to be fastened, possibly by filing notches into the rounded corners where the struts descend (see diagram), heating the brace and fitting the ends into the notches so when it cools it will provide some tension to counter the string tension. This engineer is keen to receive feedback from piano experts, thus my post.
His backup suggestion is brazing, but that will involve removing the harp and I'm not sure it is a better choice.
HISTORY: This piano was rebuilt in the 1970s in Lambertville NJ by Bob Wilson, antique piano specialist, with the assistance of my father. A crack in one treble strut was repaired by Mr. Wilson in the early 2000s by drilling and inserting a threaded pin (stitching?). The piano was shipped to Colorado about 15 years ago, regulation was done, and some months later two new cracks appeared. Mr. Wilson was consulted and didn't consider them to be a danger, and their position made it impossible to repair in the same manner, so we let them be. However, the dry climate exacerbated the issue. Two years ago, when an octave of hammers between the cracked struts stopped reaching strings, I consulted a very reputable technician who told me the piano was irreparable. The frame is 3/4 and the pinblock had tilted enough that hammer shafts contacted wood before heads reached the strings. Removing string tension, though, allowed the cracks to close, hammers to contact strings, and the keyboard to be removed when it had previously been wedged in.
I have read the pertinent sections of several online manuals as well as many posts in this group. I have also seen another Weber of the same era with the same cracks in the same position, in the next town over here in dry Colorado. I believe the cause of the cracks is twofold:
1) poor design - the struts are thicker at the bottom, while string tension stresses the top edge more.
2) dry conditions shrinking the wood
There are pictures below of the instrument (with me, my father and my son who wants to play this piano!), the struts with barely visible cracks, and a rough diagram of the brace as I understand it.
Here are the main questions, and I welcome any other comments with sincere gratitude!
1) Could this bracing solve the design problem?
2) How best to attach the braces?
3) Would it be helpful to reduce tension by lowering pitch (already below 440 for reasons of piano age and personal preference) and possibly removing 1/3 of treble strings as recommended in "Piano Owner's Survival Guide"?
4) The piano has to be moved, preferably before the work is done. Is it better to wait? Moving it to my own house will allow me to better control humidity, stop inconveniencing the friend who has been piano sitting an unplayable instrument for two+ years, and take the time to do the job right.
With heartfelt thanks,
Bonnie
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Bonnie Draina
Carbondale CO
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